Exposure to Organic Fraction Extracted from Oil Sands Process

Article pubs.acs.org/est

Cite This: Environ. Sci. Technol. 2019, 53, 7083−7094

Exposure to Organic Fraction Extracted from Oil Sands ProcessAffected Water Has Negligible Impact on Pregnancy and Lactation of Mice Chao Li,† Li Fu,†,‡ Dustin M. E. Lillico,‡ Miodrag Belosevic,‡ James L. Stafford,*,‡ and Mohamed Gamal El-Din*,† †

Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta Canada T6G 1H9 Department of Biological Sciences, University of Alberta, Edmonton, Alberta Canada T6G 2E9

Downloaded via BUFFALO STATE on July 23, 2019 at 03:19:19 (UTC). See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles.

‡

S Supporting Information *

ABSTRACT: Dissolved organic compounds are major contaminants in oil sands process-affected water (OSPW), of which naphthenic acids (NAs) are one of the main persistent toxicants. In the present study, we explore the toxic effects of the organic fraction extracted from OSPW (OSPWOF) in mice during pregnancy and lactation. Here, we report that acute oral exposure of female Balb/c mice during gestation, and subchronic exposure throughout gestation and lactation to OSPW-OF (containing naturally occurring levels of NAs found in tailings ponds), had negligible effects on their reproductive performance. Specifically, mating behavior, pregnancy success, embryonic implantation, gestation period, litter size, and offspring viability were not affected by OSPWOF containing up to 55 mg/L NAs. OSPW-OF exposure also did not affect plasma concentrations of pregnancy-associated hormones or pro- and anti-inflammatory cytokines, and it had minimal effects on liver stress gene expression. This study presents the first comprehensive in vivo analysis of mammalian toxicity associated with OSPW-OF exposure. Overall, our results suggest that the risk of acute and subchronic toxicity to mice exposed to OSPW-OF at environmentally relevant concentrations of NAs in contaminated drinking water is likely negligible.

1. INTRODUCTION The oil sands surface mining in northern Alberta employs a caustic hot water extraction method to recover bitumen, which results in the production of significant volumes of toxic oil sands process-affected water (OSPW).1,2 OSPW is a complex mixture of water and organic and inorganic compounds. The majority of the OSPW toxicity has been attributed to the organic fraction (OSPW-OF), of which naphthenic acids (NAs) are one of the persistent toxic constituents.3−6 NAs are a group of carboxylic acids with a general formula of CnH2n+zO2 (classical NAs).7 Recent advancements in highresolution mass spectrometry have identified several other types of NAs in OSPW, including oxidized, aromatic, and sulfur-/nitrogen-containing NAs.8−10 It should be noted that, the presence of additional organic contaminants (e.g., polycyclic aromatic hydrocarbons) might also contribute to the OSPW toxicity.11 Due to the complexity of OSPW, it is difficult to specifically assess the toxic effects of individual constituent(s). Consequently, the examination of the toxic effects using whole OSPW or its complex fractions (i.e., OSPW-OF) has been a focus of several studies.4,5,11−16 Under a zero-discharge practice, OSPW is accumulating in on-site tailings ponds. In order for OSPW to be reclaimed, it is © 2019 American Chemical Society

essential that the toxic pollutants be reduced. Therefore, the identification of the priority contaminants (e.g., organic fraction including NAs) and their possible toxic effects are crucial, which enables targeted treatment regimens (e.g., removal of OSPW-OF by ozone treatment or biodegradation), and helps the achievement of potential safe release of OSPW into environment. OSPW exposure causes lethality and other adverse effects to aquatic biota, including impaired immunological functions, reproductive and developmental toxicity, as well as disruption of endocrine systems11 (as reviewed by Li and colleagues in 2017). Organic compounds (e.g., the surfactant-like and estrogen-like structures of NAs) may be candidate chemicals for narcotic and endocrine disruptive effects of OSPW.17−20 Additionally, OSPW-OF may also induce oxidative stress, as suggested by the findings that reduction of organic compounds in OSPW attenuated its effects on the expression of oxidative stress responsive genes in fish.21 The oxidative stress or Received: Revised: Accepted: Published: 7083

April 1, 2019 May 2, 2019 May 21, 2019 May 22, 2019 DOI: 10.1021/acs.est.9b01965 Environ. Sci. Technol. 2019, 53, 7083−7094

Article

Environmental Science & Technology

SI. OSPW-OF was then dissolved in basic distilled water (pH ∼ 10) to a final concentration of 23.8 mg/mL NAs. For shamcontrol, the same extraction protocol was performed using distilled water, and the material obtained was dissolved in same volume of distilled water (pH ∼ 10). OSPW-OF and sham-control stock solutions were diluted in distilled water to prepare 100 μL of working solution for subsequent oral administration to mice. For the first set of exposures, the doses used were 1.82 and 18.2 mg/kg body weight/week NAs for OSPW-OF. These doses reflect the estimated amounts of NAs that an animal would consume in a week, if its drinking water contained OSPW with 1 or 10 mg/L NAs, respectively. This estimate was based on a daily water consumption of 7.8 mL per 30 g of mouse body weight.12 In addition, the concentrations of NAs used for these exposures (e.g., 1 and 10 mg/L) reflect 1−10× the possible allowable limit (1 mg/L NAs) for potential OSPW discharge. This concentration was selected according to previous studies indicating that (1) OSPW containing 1 mg/L NAs normally does not induce toxicity,13,30 and (2) the background concentrations of NAs in surface water (e.g., Athabasca River, Regional lakes) are typically around or less than 1 mg/L.31 In a separate study, OSPW-OF exposure doses of 100 mg/kg body weight/week NA was used to investigate the possibility of mice being exposed to a relatively high but unlikely NA concentration of 55 mg/L. It should be noted that, according to our UPLC/HRMS analysis, 948.45 mg total NAs were obtained, which account for 37.9% of the total mass of OSPW-OF (2.50 g), with the remaining 62.1% of the mass uncharacterized. The identification of all organic compounds and their possible toxic effects, constitutes a major analytical challenge, not given that the composition of OSPW and NAs in it varies with many factors such as ore sources, extraction process, tailings age, and remediation strategies. We standardized OSPW-OF doses based on its NA concentration, which was based on evidence suggesting that NAs are one of the primary toxic constituents in OSPW.11 In addition, the majority of studies evaluating OSPW-OF toxicity have been done according to their NA concentrations.4,5,12,23,30 However, it is worth noting that although the dosing of OSPW-OF was normalized to their NA concentrations, our study examined the toxicity of the total extracted organic fraction that consisted of ∼40% NAs. Consequently, the potential contribution of other uncharacterized organic compounds (e.g., ∼60% of the OSPW-OF) must be considered as potential contributors to OSPW-OFmediated effects. 2.2. Exposures. Six-to-eight-week-old female Balb/c mice purchased from Charles River Laboratories were fed using PicoLab mouse diet 20−5058 ad libitum and had a constant supply of fresh water. After 2 weeks of acclimatization, one adult Balb/c male mice were randomly assigned to breed with two female overnight. The presence of a vaginal plug, indicating that mating had occurred, was determined the following morning. First appearance of the plug was designated as gestation day 0 (GD 0). Females showing a vaginal plug were separated from the males prior to exposure to OSPW-OF. Beginning on GD 0, vaginal plugpositive mice were dosed weekly for 2 weeks (early- to midgestation) or 6 weeks (throughout gestation and lactation). Gavage was selected for exposure rather than dissolving the contaminants in their drinking water, to ensure that each mouse received a dose of NAs based on their individual body

disruption of endocrine processes caused by OSPW might be associated with impaired growth, development, and reproductive capacity in exposed animals.20,22 Few toxicity studies have been conducted using mammals. Rogers and co-workers (2002)23 examined the toxicity of OSPW-OF in rats. Acute exposure to high dose (300 mg/kg body weight/day) of NAs caused behavioral and histopathological changes including temporary appetite suppression and pericholangitis (a biliary inflammatory response).23 Subchronic exposure of rats using a lower dose (60 mg/kg body weight/d) of NAs also suppressed body weight, promoted excessive glycogen accumulation, and depressed plasma cholesterol levels.23 However, the exposure doses used in these studies were as much as 50 times higher than the estimated worst-case single-day exposure for wild animals. Recently, research using mice has also shown that OSPW-OF exposure at environmentally relevant concentrations of NAs caused immunotoxicity manifested by affecting macrophage microbicidal functions, and immune gene expression in different organs.4,5,12 Compared to the extensive information on reproductive and developmental toxicity of OSPW in aquatic organisms,11 limited research has been performed on mammals. A single in vivo study demonstrated impaired embryonic implantation in rats after exposure to NAs extracted from OSPW, which was likely associated with the changes in cholesterol availability and a parallel decrease in progesterone levels.24 Studies have also shown that OSPW-OF affected the expression of cardiac specific markers in differentiating mouse embryonic stem cells (ESCs), which may potentially result in developmental abnormalities.25 Overall, these findings suggested that OSPW-OF (including NAs) may specifically affect mammalian reproduction and development. The aim of this study was to determine the possible adverse effects of OSPW-OF when orally administered to mice, at naturally occurring levels of NAs in tailings ponds, during gestation and lactation; critical periods of reproduction and development.

2. MATERIALS AND METHODS 2.1. Extraction of the Organic Fraction from OSPW. OSPW was collected from an active tailings pond in Fort McMurray, Alberta, Canada in 2013. Upon delivery, OSPW was stored in high density polyethylene (HDPE) barrels in a cold room at 4 °C in the dark. We conducted a complete characterization of the OSPW as soon as we started our experiments, avoiding any impact of the storage time on our tests. Also, according to our consistent analyses throughout storage, OSPW showed no significant differences between samples when received fresh and samples stored for a prolonged period of time before use, indicating that no biological degradation or adsorption on the surface of the barrels had occurred. In this study, the organic fraction was extracted from OSPW using a liquid−liquid extraction protocol exactly as described.5 Briefly, liquid−liquid extraction using dichloromethane (DCM) is an efficient method to extract NAs and other organic compounds from OSPW.5,26 DCM is highly volatile and thus can easily removed from the dried residue before reconstitution of the OSPW-OF for toxicity testing.4,5,12,27 Further details of this extraction process are provided as Supporting Information (SI). The amounts of NAs (CnH2n+zO2) and oxy-NAs (CnH2n+zO3−6) present in both whole OSPW and OSPW-OF were analyzed by UPLC/HRMS using the internal calibration method,28,29 as described in the 7084

DOI: 10.1021/acs.est.9b01965 Environ. Sci. Technol. 2019, 53, 7083−7094

Article


performed by a certified veterinary pathologist (Dr. Nick Nation, University of Alberta). 2.7. Statistical Analysis. Unless indicated otherwise, data are presented as mean ± standard error of the mean (SEM). Statistical analysis was performed using one-way ANOVA, followed by the Dunnett’s post hoc test. Normality and variance tests were performed using D’Agostino and Pearson omnibus normality test and Bartlett’s test, respectively. All analyses were performed using Prism 6.0 (Graphpad software, La Jolla, CA). Differences between treatment groups were considered statistically significant at p < 0.05.

weight. The nonmated and nonexposed female mice were housed in separate cages and used as the nonpregnant controls. During exposure periods, the common clinical health conditions of mice (e.g., lethargy, ruffled fur, diarrhea, skin lesions, mobility issues, respiratory issues, etc.) were checked daily by experienced registered laboratory animal technicians. Their body weights were measured weekly. For the two-week postexposure assessments, animals were anesthetized on GD 14. The blood was collected by cardiac puncture, immediately followed by plasma preparation for hormone and cytokine assays. Mice were euthanized, and the liver and spleen removed for gene expression and histology analysis. The uteri were examined for implantations and fetal resorptions. Resorbing fetuses were identified by their notably smaller size and necrotic or hemorrhagic appearance, as shown in SI Figure S1. Healthy fetuses were separated and weighed. For the sixweek postexposure group, mice were allowed to deliver, and the day of parturition was regarded as postnatal day 0 (PND 0). The litter size and offspring-related parameters (viability and gross external morphological abnormalities) were recorded. The body weight of both dams and pups were measured each week. After 6 weeks, the dams were sacrificed. Their plasma was prepared for hormone and cytokine measurement, and the liver and spleen collected from dams for gene expression and histology analysis. 2.3. Plasma Hormone Analysis. Progesterone (P4), 17βestradiol (E2), and prolactin were measured using rodent ELISA kits according to the manufacturer’s instructions. The limits of sensitivity of the assays were for 0.04 ng/mL for P4 (cat# 55-PROMS-E01, ALPCO, Salem, NH), 3 pg/mL for E2 (cat# ES180S-100, Calbiotech, El Cajon, CA), and 30 pg/mL for prolactin (cat# ab100736, Abcam, Cambridge, MA). 2.4. Plasma Cytokine Analysis. Cytokine levels were analyzed using the Mouse Cytokine/Chemokine Array 31-Plex (Cat No. MD31, Eve Technologies, Calgary, AB, Canada). This assay permitted simultaneous quantification of multiple cytokines using a bead-based capture procedure and analyzer (Bio-Plex 200, Bio-Rad, Hercules, CA). The cytokines monitored in this study were: Interleukin (IL)-1α, IL-1β, IL5, IL-9, IL-13, granulocyte colony-stimulating factor (G-CSF), and granulocyte-macrophage colony-stimulating factor (GMCSF). The cytokine concentrations were calculated based on the standard curves. 2.5. Gene Expression. The details for gene expression analyses are described in the SI. The stress responsive and detoxification genes examined in liver and spleen were glutathione S-transferase pi 1 (gstp1), glutathione S-transferase mu 1 (gstm1), heme oxygenase 1 (hmox1), DNA ligase 1 (lig1), 8-oxoguanine DNA glycosylase (ogg1), growth arrest and DNA damage-inducible protein 45 (gadd45), uracil-DNA glycosylase (ung), and proliferating cell nuclear antigen (pcna). Hypoxanthine-guanine phosphoribosyltransferase (hprt1) was used as the endogenous control. Gene expression was analyzed using the ddCT method, normalizing relative quantitation (RQ) values for treatment groups to the sham-control. 2.6. Histology. Liver, spleen, kidney, placenta, intestine, brain, and lung were collected from OSPW-OF dosed and sham-control mice. The tissues were processed by fixation (in 4% formaldehyde solution), dehydration, embedding (in paraffin) and sectioning, followed by the deparaffinization and rehydration. Samples were then stained with hematoxylineosin (H&E) for microscopic examination, which was

3. RESULTS 3.1. Analysis of NAs in OSPW and OSPW-OF. Classical NAs (18.38 mg/L) were the predominant NAs within the OSPW (SI Table S2). The overall fractional distribution of NAs with various Z and C numbers are illustrated in SI Figures S2 and S3. Overall, 40 NAs were detected in the whole OSPW, and those with Z = −4, −6, and C number ranging from 13 to 16 constituted the largest proportion of NA mixtures. The NA profile of OSPW in this study was similar to that from Syncrude’s West-in-pit.4,5 As shown in SI Table S3, classical NAs were effectively isolated from OSPW using the liquid− liquid organic extraction process, with an extraction rate >80%. The extraction rate of oxidized NAs from OSPW is lower than that of classical NAs (SI Table S3), which is because the additional hydroxyl group(s) enhanced the water solubility of oxidized NAs, compared to classical NAs, resulting in the decreased liquid−liquid extraction rate.26,28 3.2. Pregnancy Outcomes Following OSPW-OF Exposure. Throughout gestation and lactation, mice from all groups had no signs of morbidity, mortality, behavioral changes, or changes in their general appearance. Various reproductive parameters were determined in mice acutely exposed to OSPW-OF. As shown in Table 1, mice exposed to 1 mg/L and 10 mg/L had pregnancy rates comparable to sham-controls, and mice from all groups had a median value of 9 embryos/mouse. Regarding fetal resorptions (indicative of a Table 1. Reproductive Parameters of Mice after Acute Exposure to OSPW-OF (1 and 10 mg/L NAs)a OSPW-OF parameters no. of females no. of pregnant mice pregnancy rateb (%) no. of implantations/ damc resorption rated (%) fetus weight (g) placental weight (g)

sham-control (n = 15)

1 mg/L NAs (n = 15)

10 mg/L NAs (n = 16)

24 15

24 15

24 16

62.5 9

62.5 9

66.7 9

23.78 ± 4.27 0.153 ± 0.005 0.099 ± 0.003

27.43 ± 4.46 0.162 ± 0.014 0.091 ± 0.004

32.60 ± 4.53 0.158 ± 0.005 0.097 ± 0.002

a

Females were gavaged weekly with OSPW-OF (1 and 10 mg/L NAs), OSPW+O3-OF and the sham-control, for 2 weeks beginning on GD 0. On GD 14, female mice were euthanized, and reproductive parameters were recorded. Values in rows five to seven represent the mean ± SEM. Statistical analysis was performed using one-way ANOVA with Dunnett’s post hoc test. bNumber of pregnant mice/ number of female mice mated ×100. cMedian value. dNumber of resorptions/number of implantations ×100. 7085


Article


nancy. In agreement with previous studies,32,33 significant increases in the levels of these two hormones (∼3.5-fold and ∼1-fold increase, respectively) were observed in mice on GD 14 (Figure 1). Prolactin, a hormone that promotes the

fetus that died in utero), mice exposed to OSPW-OF at 10 mg/L NAs had higher resorption rates than sham-controls, but the difference was not statistically significant. Finally, as shown in SI Table S4, acute exposure using the higher dose of OSPWOF (containing 55 mg/L NAs) did not cause any significant changes in all reproductive parameters examined. For the subchronic (e.g., six week) exposure, OSPW-OF treatments at 1 mg/L and 10 mg/L NAs did not affect fecundity (Table 2). However, a slight but nonsignificant Table 2. Reproductive Parameters of Mice after Subchronic Exposure to OSPW-OF (1 and 10 mg/L NAs)a OSPW-OF parameters no. of females no. of pregnant mice pregnancy rateb (%) gestation lengthc litter size live-birth indexd (%) viabilitye (%) weaning indexf (%)

sham-control (n = 13)

1 mg/L NAs (n = 15)

10 mg/L NAs (n = 13)

18 13

18 15

18 13

72.2

83.3

72.2

20 6.23 ± 0.53 98.90 ± 1.10

20 5.73 ± 0.45 99.26 ± 0.74

20 5.62 ± 0.53 100 ± 0.00

100 ± 0.00 100 ± 0.00

100 ± 0.00 100 ± 0.00

100 ± 0.00 100 ± 0.00

Figure 1. Hormonal levels in plasma of nonmated control, pregnant control (GD 14) and nonexposed mice at the end of lactation (PND 21). The plasma concentrations of three hormones (progesterone, 17β-estradiol and prolactin) were measured. Data represent the mean ± SEM (n = 3 for nonpregnant control, 12 for pregnant control, and 9 for nonexposed mice on PND 21). For each hormone, statistical analysis was performed using one-way ANOVA with Dunnett’s post hoc test. * denotes statistically significant differences at p < 0.05.

a

Females were gavaged weekly with OSPW-OF (1 and 10 mg/L NAs), OSPW+O3-OF and the sham-control, for 6 weeks beginning on GD 0. On GD 14, Mice were allowed to deliver. After 6 weeks, dams and pups were euthanized, and reproductive parameters were recorded. Values in rows five to eight represent the mean ± SEM. Statistical analysis was performed using one-way ANOVA with Dunnett’s post hoc test. bNumber of pregnant mice/number of female mice mated× 100. cMedian value. dnumber of live offspring/ litter size ×100. enumber of live offspring at PND 4/number of live offspring delivered ×100. fnumber of live offspring at end of lactation/ number of live offspring born ×100.

development of mammary glands and enhances milk production34,35 was also measured. Prolactin circulating concentrations are high during pregnancy,36 which was also observed in our study as ∼5.5 increase of prolactin levels in mice on GD14 relative to the nonmated control animals (Figure 1). The plasma concentrations of all hormones at the end of lactation (PND 21) returned to the basal levels observed in nonmated mice (Figure 1). This systemic reduction suggests postpartum adaptation of maternal physiology from parturition to the end of lactation. 3.4.2. Hormone Levels in Mice after Exposure to OSPWOF. When compared with sham-control mice, oral administration of 1 mg/L, and 10 mg/L OSPW-OF did not affect the plasma concentrations of 17β-estradiol (E2), progesterone (P4), or prolactin in mice on GD 14 (Figure 2). As shown in SI Figure S6, even at the highest dose tested (OSPW-OF containing 55 mg/L NAs), negligible changes in plasma hormone concentrations were observed in mice after acute exposure. By the end of lactation (PND 21), the hormone levels returned to basal levels and once again, no significant differences were observed between sham-control animals and those treated with OSPW-OF containing as much as 55 mg/L NAs (data not shown). 3.5. Effects of OSPW-OF Exposure on Cytokine Levels. 3.5.1. Cytokine Profiles during Normal Pregnancy and Lactation in Mice. During pregnancy, a polarization of the immune system from a T-helper type 1 (Th1) to a Thelper type 2 (Th2)-type response occurs to help promote fetal tolerance.37 Consequently, we monitored the circulating concentrations of Th1 and Th2 cytokines in nonmated females and nonexposed pregnant mice. As shown in Figure 3, IL-9 and IL-13 (Th2 cytokines) increased from 33.6 and 15.9 pg/ mL to 57.3 and 33.1 pg/mL, respectively, though the differences were not statistically significant. The growth factor

reduction of litter size was observed in OSPW-OF exposed mice. The viability of pups throughout lactation was not affected by chronic OSPW-OF exposure at these doses (Table 2) and as shown in SI Table S5, exposure to the higher dose of OSPW-OF (containing 55 mg/L NAs) also had no significant affects on mouse reproductive capacity or offspring survival. 3.3. Body Weights after OSPW-OF Exposure. The body weight of dams and their offspring were recorded weekly for each group. After subchronic exposure to OSPW-OF containing NAs up to 55 mg/L, no significant changes of body weight were observed in the female mice (SI Figure S4) or their pups (SI Figure S5). Dams from both groups gained body weight during pregnancy, and then experienced notable weight loss at week 3 when they delivered their pups (SI Figure S4). 3.4. Effects of OSPW-OF Exposure on Hormone Levels. 3.4.1. Dynamics of Hormones during Normal Pregnancy and Lactation in Mice. Reproduction in mammals is dependent on timely production and concentration of specific hormones. We measured the levels of three important steroid hormones (progesterone, 17β-estradiol, and prolactin) in nonmated females/nonexposed mice on GD 14 and PND 21. Both 17β-estradiol (E2) and progesterone (P4) are important hormones that play crucial roles in the control of embryo implantation and maintenance of successful preg7086


Article


Figure 2. Hormonal levels in plasma of pregnant mice after acute exposure to OSPW-OF (1, 10 mg/L NAs). Animals were gavaged weekly with OSPW-OF (1 and 10 mg/L NAs), and their sham-control for 2 weeks beginning on GD 0. On GD 14, pregnant mice were euthanized. The plasma concentrations of three hormones (A: progesterone; B: 17β-estradiol and C: prolactin) were determined using commercial ELISA kits. Data represent the mean ± SEM (n = 11−12 for A, 8−9 for B, and 11−12 for C). For each hormone, statistical analysis was performed using one-way ANOVA with Dunnett’s post hoc test.

Figure 3. The profile of T-helper type 1 (Th1) and T-helper type 2 (Th2) cytokines in plasma of nonmating control, pregnant control (GD 14) and nonexposed mice at the end of lactation (PND 21). Data represent the mean ± SEM (n = 3 for nonpregnant control, 12 for pregnant control, and 9 for nonexposed mice on PND 21). For each cytokine, statistical analysis was performed using one-way ANOVA with Dunnett’s post hoc test. * denotes statistically significant differences at p < 0.05.

Figure 4. Profile of Th1 and Th2 cytokines in plasma of pregnant mice after acute exposure to OSPW-OF (1, 10 mg/L NAs). Animals were gavaged weekly with OSPW-OF containing 1 mg/L NAs (n = 12), or 10 mg/L NAs (n = 11), and their sham-control (n = 12), for 2 weeks beginning on GD 0. On GD 14, pregnant mice were euthanized. The plasma levels of cytokines were measured. Data represent the mean ± SEM. For each cytokine, statistical analysis was performed using one-way ANOVA with Dunnett’s post hoc test. * denotes statistically significant differences at p < 0.05.

G-CSF, a cytokine that showed a marked antiabortion activity,38,39 significantly increased from basal level of 89.7 pg/mL to 150 pg/mL on GD14. Regarding the Th1 cytokines, the plasma levels of IL-1α, IL-1β, and GM-CSF in midgestation did not differ from nonmated control mice. After 3 weeks postparturition, the protein level of G-CSF and other cytokines returned to the baseline level at the end of lactation (Figure 3). 3.5.2. Cytokine Profiles in Mice after Exposure to OSPWOF. The circulating concentrations of cytokines in OSPW-OFexposed mice on GD 14 and sham-control animals are shown in Figure 4. The Th1/Th2 cytokine profiles in pregnant mice were not affected by OSPW-OF exposure of 1 mg/L or 10 mg/ L NAs. When the OSPW-OF dose was increased to 55 mg/L NAs, the cytokine concentrations in treated mice were also comparable to those of sham-control animals (SI Figure S7). Again, continuous exposure to OSPW-OF at all doses throughout gestation and lactation (6 weeks) did not significantly alter the plasma levels of any cytokines tested (data not shown).

3.6. Expression of Stress Responsive and Detoxification Genes in the Liver and Spleen of Mice after Exposure to OSPW-OF. Hepatotoxicity caused by OSPW and OSPW-OF has been reported both in vitro,40,41 and in vivo.23 In the present study, the toxic effects of OSPW-OF in the mouse livers were examined by measuring the expression of the following genes to track potential changes in xenobiotic biotransformation (gstp1, gstm1), oxidative stress (hmox1), DNA repair activity (lig1, ung, ogg1), cell proliferation, and growth arrest functions (pcna, gadd45). The expression of these genes were also investigated in the spleen, to determine whether acute exposure to OSPW-OF caused stress to this major immune organ of mice. As shown in Figure 5, after a two-week exposure to OSPW-OF (e.g., containing 1 mg/L and 10 mg/L NAs), all the genes in the liver and spleen were expressed at levels that were not statistically different from those of nonexposed animals. When the exposure was prolonged to 6 weeks, the mRNA level of hmox1 was slightly down-regulated at 10 mg/L NAs (Figure 6). At a higher dose of OSPW-OF (containing 55 mg/L NAs), mice acutely 7087


Article


Figure 5. Gene expression in the liver and spleen of pregnant mice after acute exposure to OSPW-OF (1, 10 mg/L NAs). Gene expression was assessed in the liverand spleen of pregnant mice after acute exposure to OSPW-OF containing 1 mg/L NAs (n = 7), or 10 mg/L NAs (n = 6), and the sham-control (n = 7) for 2 weeks. Gene expression was analyzed by qPCR using the ddCT method. Data are expressed as relative quantification (RQ) values. RQ values for the treatment groups were normalized against the RQ values of shamcontrol. Data represent the mean ± SEM. For each gene, statistical analysis was performed using one-way ANOVA with Dunnett’s post hoc test.

Figure 6. Gene expression in the liver and spleen of female mice after subchronic exposure to OSPW-OF (1, 10 mg/L NAs). Gene expression was assessed in the liver and spleen of mice after subchronic exposure to OSPW-OF containing 1 mg/L NAs (n = 10), or 10 mg/L NAs (n = 9), and the sham-control (n = 9) for 6 weeks. Gene expression was analyzed by qPCR using the ddCT method. Data are expressed as relative quantification (RQ) values. RQ values for the treatment groups were normalized against the RQ values of sham-control. Data represent the mean ± SEM. For each gene, statistical analysis was performed using one-way ANOVA with Dunnett’s post hoc test. * denotes statistically significant differences at p < 0.05.

exposed exhibited a subtle down-regulation of mRNA levels of gstp1, gstm1, and ogg1 in the liver (SI Figure S8). Surprisingly, following subchronic exposure to the high dose of OSPW-OF (containing 55 mg/L NAs), no significant changes in the transcripts of all genes, except ung, were observed in the liver (SI Figure S9). 3.7. Histological Assessments after Exposure to OSPW-OF. Tables 3 and 4 summarize the histopathological findings in various tissues of mice after acute and subchronic exposure to OSPW-OF, respectively. There were some minor effects on the liver (mild lipid vacuolation) and spleen (mild hyperplasia of lymphoid germinal centers) in some animals after exposure to OSPW-OF at 55 mg/L NAs for 2 weeks (SI Figure S10), but they were indicated to be normal physiologic reactions and not pathologic. In the other tissues, no pathological changes were observed in mice exposed to all doses of OSPW-OF that would be indicative of tissue damage, inflammation, or neoplasia.

cytokines shift) adaptation of the mother to the semiallogeneic fetus. OSPW-OF-induced changes in hormone levels have been reported both in vitro and in vivo.24,42 Also, we previously reported that OSPW-OF acts as an immunomodulatory agent by altering the cytokines/chemokines genes involved in the regulation of important immune responses.4,5,12 These results suggested that the OSPW-OF may impair pregnancy by perturbing endocrine and immune systems. To explore this possibility, the reproductive performance combined with the production of pregnancy-associated hormones, and cytokines/chemokines were assessed following acute and subchronic exposure of mice using estimated environmentally relevant concentrations of OSPW-OF. The expression of stress responsive genes and genes involved in detoxification process in liver and spleen were also analyzed. In a previous study, the reproductive failure in female rats after exposure to NAs extracted from OSPW was reported.24 The mechanisms of reproductive toxicity appeared to involve an effect on sex hormone production.24 Adequate and accurate production of sex hormones, like progesterone and estradiol, are required for normal mating behavior, implantation, and maintenance of pregnancy. In the present study, we found that repeated exposure to OSPW-OF containing the estimated environmentally relevant NA concentrations (e.g., 1 mg/L-10 mg/L NAs), or even at an ∼5 times greater level (e.g., 55 mg/

4. DISCUSSION The objective of this study was to determine whether oral exposure of OSPW-OF posed a significant health risk during the critical periods of pregnancy and lactation. Pregnancy is a comprehensive process that requires the fine-tuned endocrine (hormonal changes) and immune (T helper 1 (Th1)/Th2 7088


no microscopic changes relative to sham-control






spleen

placenta

intestine

kidney

brain

lung

1 and 10 mg/L NAs


tissue

liver

55 mg/L NAs

7089






mild hyperplasia of lymphoid germinal centers (a nonspecific change indicating antigenic stimulation)

mild lipid vacuolation and cytoplasmic stippling (cytoplasmic effects)

OSPW-OF summary the intestine, kidney, placenta, brain, and lungs of mice exposed to OSPW-OF had no significant microscopic changes compared to sham-control; there were some mild effects on the livers and spleens of some animals from 55 mg/L group, but they were suggested to be normal physiologic reactions, not pathologic

Table 3. Histopathology Report Summary for Various Tissues from Mice after Acute Exposure to OSPW-OF

Environmental Science & Technology Article


Article

Environmental Science & Technology Table 4. Histopathology Report Summary for Various Tissues from Mice after Subchronic Exposure to OSPW-OF OSPW-OF tissuea liver spleen intestine kidney brain lung

1, 10, and 55 mg/L NAs no microscopic changes relative to sham-control no microscopic changes relative to sham-control no microscopic changes relative to sham-control no microscopic changes relative to sham-control no microscopic changes relative to sham-control no microscopic changes relative to sham-control

summary no significant difference was found between the treatment and sham-control groups. It was concluded that exposure to OSPW-OF at these doses had no microscopic anatomic effects on mice

a

Liver and spleen tissues were collected from both dams and pups. Other tissues were only collected from dams.

did not significantly affect normal reproductive physiology. Three-week postparturition, the maternal cytokine profiles of nonexposed mice returned to baseline. Considering the importance of cytokines in health and disease, especially in host defense from infections, we examined whether subchronic exposure to OSPW-OF altered their plasma concentrations at the end of lactation. Our laboratory previously demonstrated that subchronic OSPW-OF treatment at dose equivalent to 55 mg/L NAs caused a down-regulation of the expression of genes encoding pro-inflammatory cytokines in the liver and spleen of mice.5 Interestingly, the results in the present study showed that the protein profiles of several cytokines were not affected by exposure to OSPW-OF containing NAs up to 55 mg/L. This may be explained by the differences in OSPW sources (West In Pit pond versus Aurora tailings pond) or more likely that mRNA levels do not necessary parallel the secretion levels of cytokine proteins. In female mammals, reproduction is energy-demanding and might have negative impacts on survival and other physiological functions.51 The limited resources available to animals are delicately balanced and require a trade-off between survival (somatic protection) and reproduction. When animals are stressed, their energy is directed toward processes that will restore homeostasis, and away from reproduction.52 Oxidative stress has been suggested as a cost of somatic maintenance that may limit investment of energy resources on reproduction.53,54 Oxidative stress occurs when the rate of ROS production exceeds the capacity of the antioxidant defense and repair mechanisms.53,55,56 This is associated with a variety of disease conditions, including reproductive complications (spontaneous abortion, recurrent pregnancy loss, preeclampsia)57,58 and embryonic development.59 Several studies have established a link between OSPW exposure and increased oxidative stress,14,40,60 which for example induce cellular apoptosis and impairment of the development of fish embryos.14 Organisms have a variety of defense mechanisms to combat the threat of oxidative stress and its associated damage.61 Specifically, glutathione S-transferase (GST) is an antioxidant family that facilitates detoxification of xenobiotics, together with superoxide dismutase (SOD) and catalase (CAT), these play important functions in detoxification of ROS.14,61 Increased abundance of transcripts for the genes that encode enzymes of the antioxidant pathway suggested that there was greater production of ROS in animals exposed to OSPW. For example, Gagné and colleagues60 used hepatocytes from rainbow trout and reported up-regulation of gst and sod genes after exposure

L NAs) throughout pregnancy and lactation did not affect the pregnancy success, embryonic implantation, gestation length, litter size, and offspring viability in mice. The results of pregnancy-associated hormones supported the normal reproductive performance by showing anticipated circulating concentrations of progesterone, estradiol, and prolactin in OSPW-OF treated mice compared to the sham-exposed control animals. Previous research has also shown that OSPW and OSPWOF induced immunotoxicity in fish, birds, and mammals. For example, chronic exposure to OSPW, at concentrations of NAs within the range used in the present study, caused a higher occurrence of virally induced tumors in fish43 and greater prevalence of infestation with bird blow flies in tree swallows.44 Several studies have also reported that OSPW or OSPW-OF affected the immune system of vertebrates by altering the expression of genes encodings cytokines and thereby decreasing the ability of hosts to control infectious diseases.4,5,12,30 Pregnancy creates a unique immune response profile that is normally associated with a polarization from a Th1 cytokine profile (e.g., pro-inflammatory cytokines) to a Th2 cytokine profile (e.g., anti-inflammatory cytokines) that promotes fetal tolerance by the mothers immune system.45 Consequently, this shift in the types of cytokines produced during pregnancy decreases the cell-mediated immune response and enhances humoral antibody-based immunity.46 This modulation in immune responsiveness during gestation is carefully controlled, leading to different responses depending on exposure to different pathogens and the specific stages of pregnancy.46−48 In addition, maternal immunity is also regulated by sex hormones, as progesterone and estradiol both promote the T helper 2 cell cytokine production profile and are thus likely partially responsible for the Th2 bias associated with pregnancy.37,49,50 We also observed Th1/Th2 bias during normal midgestation, as shown by a significant increase of Th2 cytokine G-CSF (a growth factor with a marked antiabortion activity) in nontreated pregnant mice on GD 14. The parallel increases were also observed in plasma concentrations of the three hormones (progesterone, estradiol and prolactin) in midpregnancy. The aberrant Th1/Th2 cytokine balance during gestation has been shown to exert deleterious effects on pregnancy, including early fetal loss, preeclampsia and preterm labor.37 Interestingly, acute exposure to OSPW-OF at a range of NA concentrations (i.e., 1−55 mg/L NAs) did not alter cytokine profiles in pregnant mice, suggesting that OSPW-OF 7090


Article


organ. However, no histopathological changes in mouse livers were observed. Identification of the main toxic components (priority pollutants) in OSPW is important, which may allow targeted treatment regimens (e.g., removal of OSPW-OF or NAs by ozone treatment or biodegradation), and perhaps the eventual safe release of detoxified OSPW. It is well-known that OSPW represents an extremely complex mixture of organic and inorganic compounds, though no mammalian toxicity studies focused on whole OSPW exposure have been performed. Future investigation of the toxicity of whole OSPW is needed, using parallel assessments of toxic effects induced by whole OSPW, OSPW-OF, or other fractions to assess the potential additive and/or synergistic effects between different OSPW fractions. Also, given that OSPW chemistry varies considerably between tailing ponds, it is imperative that a comprehensive side-by-side comparative data sets of the toxic effects induced by different OSPWs be generated. Furthermore, the laboratory-derived toxicity results could differ from the toxic effects on animals in the wild, due to several factors such as stress, food limitation, predation, and diseases. Therefore, careful interpretation and extrapolation of the toxicological effects are required for a risk assessment of OSPW exposure on living organisms including humans.

to OSPW. Similar changes in gene expression were reported following exposure of fathead minnow embryos to OSPW.14 These observations were inconsistent with the results in the present study whereby acute exposure to OSPW-OF slightly down-regulated the mRNA levels of gst. The mechanism for the suppression in gst gene expression is unknown, however, the inhibition of GST enzyme activity in trout hepatocytes after exposure to the OSPW extracts41,62 suggests that some organometallic compound(s) that are present in OSPW may participate in GST enzyme inhibition. The inhibition of gst gene expression and enzyme activity may create an imbalance between the ROS production and the quantities of antioxidants required to restore homeostasis. In this study, after subchronic exposure to OSPW-OF, the expression of the gst gene was reversed (slight elevation), suggesting a shift toward enhanced detoxification after prolonged period of stress. Further studies would be required to understand this phenomenon. ROS also induces oxidative damage to molecules such as lipids, proteins, and DNA.63 Animals have protection mechanisms to mitigate the DNA damage by the induction of various enzymes involved in DNA repair activity.64 In a previous study, rainbow trout hepatocytes exposed to OSPW exhibited genotoxicity as demonstrated by the PAH-DNA adducts, DNA strand breaks, and increased expression of genes encoding enzymes that function to repair DNA damage: ung and ogg.40,41,60 In our study, an elevation in ung gene expression was also observed in the liver of reproductive mice after subchronic exposure to OSPW-OF at 55 mg/L NAs, which indicated a possible increase in OSPW-OF induced mutagenesis, as the protein UNG functions to eliminate uracil (a base normally present in RNA) from DNA. Interestingly, acute exposure to OSPW-OF caused a reduction in the expression of ogg, which encodes DNA glycosylase that initiates the base-excision repair pathway for repair of nonbulky oxidative DNA lesions.65 However, this effect was transitory and not observed after subchronic exposure to the relatively high dose of OSPW-OF (containing 55 mg/L NAs). These results suggest both time- and dose-dependent effects of OSPW-OF on DNA repair gene expression. It should be noted that despite the changes in liver gene expression that may be indicative of hepatotoxicity, we did not observe significant alterations in liver histopathology following exposure to OSPW-OF at all doses tested. Overall, the results of this study provide a comprehensive evaluation on the possible effects of OSPW-OF exposure on the reproduction in mice. These results were obtained from OSPW-OF exposure at naturally occurring levels of NAs in tailings ponds. It is suggested that the risk of acute and subchronic toxicity to mice exposed to OSPW-OF containing environmentally relevant NA concentrations and other uncharacterized organic compounds in contaminated drinking water is low. No significant signs of distress (death, behavior changes, loss of body weight, pregnancy failure, growthretarded pups) were associated with the oral administration of OSPW-OF to mice acutely (2-week) or subchronically (6week). OSPW-OF exposure did not change the circulating concentrations of hormones or Th1/Th2 cytokine profile in mice, implying that the endocrine and immune systems were not significantly disrupted. Specific stress response and detoxification genes were slightly altered in livers at high dose of OSPW-OF, indicating that liver might be a target

■

ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.est.9b01965. OSPW-OF preparation; NAs analysis; gene expression analysis; sequence of the investigated genes in a RT− PCR analysis (Table S1); NAs analysis for OSPW (Table S2); extraction rate of NAs from OSPW (Table S3); reproductive parameters of mice after acute exposure to OSPW-OF (55 mg/L NAs) (Table S4); reproductive parameters of mice after subchronic exposure to OSPW-OF (55 mg/L NAs) (Table S5); representative picture of the feto−maternal interface of a pregnant mouse (Figure S1); NAs and oxy-NAs profiles of OSPW (Figure S2); composition of Z-family and Cfamily of NAs in OSPW (Figure S3); body weight of dams during subchronic exposure (Figure S4); body weight of pups (Figure S5); hormonal levels in plasma of pregnant mice after acute exposure to OSPW-OF (55 mg/L) (Figure S6); cytokine profile in plasma of pregnant mice after acute exposure to OSPW-OF (55 mg/L) (Figure S7); gene expression in the liver and spleen of pregnant mice after acute exposure to OSPWOF (55 mg/L) (Figure S8); gene expression in the liver and spleen of female mice after subchronic exposure to OSPW-OF (55 mg/L) (Figure S9); representative histological images of spleen and liver from pregnant mice after acute exposure to OSPW-OF (55 mg/L NAs) (Figure S10) (PDF)

■

AUTHOR INFORMATION

Corresponding Authors

*(J.L.F.) Phone: +1 780 492 9258; e-mail: stafford@ualberta. ca. *(M.G.E.-D.) Phone: +1 780 492 5124; e-mail: [email protected]. 7091


Article

Environmental Science & Technology ORCID

Process-Affected Water: Structural Comparisons with Environmental Estrogens. Environ. Sci. Technol. 2011, 45 (22), 9806−9815. (11) Li, C.; Fu, L.; Stafford, J.; Belosevic, M.; Gamal El-Din, M. The Toxicity of Oil Sands Process-Affected Water (OSPW): A Critical Review. Sci. Total Environ. 2017, 601−602, 1785−1802. (12) Garcia-Garcia, E.; Pun, J.; Hodgkinson, J.; Perez-Estrada, L. A.; Gamal El-Din, M.; Smith, D. W.; Martin, J. W.; Belosevic, M. Commercial Naphthenic Acids and the Organic Fraction of Oil Sands Process Water Induce Different Effects on Pro-Inflammatory Gene Expression and Macrophage Phagocytosis in Mice. J. Appl. Toxicol. 2012, 32 (12), 968−979. (13) Hagen, M. O.; Katzenback, B. A.; Islam, M. D. S.; Gamal ElDin, M.; Belosevic, M. The Analysis of Goldfish (Carassius Auratus L.) Innate Immune Responses After Acute and Subchronic Exposures to Oil Sands Process-Affected Water. Toxicol. Sci. 2014, 138 (1), 59− 68. (14) He, Y.; Patterson, S.; Wang, N.; Hecker, M.; Martin, J. W.; Gamal El-Din, M.; Giesy, J. P.; Wiseman, S. B. Toxicity of Untreated and Ozone-Treated Oil Sands Process-Affected Water (OSPW) to Early Life Stages of the Fathead Minnow (Pimephales Promelas). Water Res. 2012, 46 (19), 6359−6368. (15) Fu, L.; Li, C.; Lillico, D. M.; Phillips, N. A.; Gamal El-Din, M.; Belosevic, M.; Stafford, J. L. Comparison of the Acute Immunotoxicity of Nonfractionated and Fractionated Oil Sands Process-Affected Water Using Mammalian Macrophages. Environ. Sci. Technol. 2017, 51, 8624−8634. (16) Frank, R. A.; Kavanagh, R.; Burnison, B. K.; Arsenault, G.; Headley, J. V.; Peru, K. M.; Van Der Kraak, G.; Solomon, K. R. Toxicity assessment of collected fractions from an extracted naphthenic acid mixture. Chemosphere 2008, 72, 1309−1314. (17) He, Y.; Wiseman, S. B.; Hecker, M.; Zhang, X.; Wang, N.; Perez, L. A.; Jones, P. D.; Gamal El-Din, M.; Martin, J. W.; Giesy, J. P. Effect of Ozonation on the Estrogenicity and Androgenicity of Oil Sands Process-Affected Water. Environ. Sci. Technol. 2011, 45 (15), 6268−6274. (18) He, Y.; Wiseman, S. B.; Zhang, X.; Hecker, M.; Jones, P. D.; Gamal El-Din, M.; Martin, J. W.; Giesy, J. P. Ozonation Attenuates the Steroidogenic Disruptive Effects of Sediment Free Oil Sands Process Water in the H295R Cell Line. Chemosphere 2010, 80 (5), 578−584. (19) Scarlett, A. G.; Reinardy, H. C.; Henry, T. B.; West, C. E.; Frank, R. A.; Hewitt, L. M.; Rowland, S. J. Acute Toxicity of Aromatic and Non-Aromatic Fractions of Naphthenic Acids Extracted from Oil Sands Process-Affected Water to Larval Zebrafish. Chemosphere 2013, 93 (2), 415−420. (20) Wiseman, S. B.; Anderson, J. C.; Liber, K.; Giesy, J. P. Endocrine Disruption and Oxidative Stress in Larvae of Chironomus Dilutus Following Short-Term Exposure to Fresh or Aged Oil Sands Process-Affected Water. Aquat. Toxicol. 2013, 142−143, 414−421. (21) Wiseman, S. B.; He, Y.; Gamal-El Din, M.; Martin, J. W.; Jones, P. D.; Hecker, M.; Giesy, J. P. Transcriptional Responses of Male Fathead Minnows Exposed to Oil Sands Process-Affected Water. Comp. Biochem. Physiol., Part C: Toxicol. Pharmacol. 2013, 157 (2), 227−235. (22) He, Y.; Wiseman, S. B.; Wang, N.; Perez-Estrada, L. A.; Gamal El-Din, M.; Martin, J. W.; Giesy, J. P. Transcriptional Responses of the Brain−Gonad−Liver Axis of Fathead Minnows Exposed to Untreated and Ozone-Treated Oil Sands Process-Affected Water. Environ. Sci. Technol. 2012, 46 (17), 9701−9708. (23) Rogers, V. V.; Wickstrom, M.; Liber, K.; MacKinnon, M. D. Acute and Subchronic Mammalian Toxicity of Naphthenic Acids from Oil Sands Tailings. Toxicol. Sci. 2002, 66 (2), 347−355. (24) Rogers, V. Mammalian toxicity of naphthenic acids derived from the Athabasca oil sands (Thesis/Dissertation) | ETDEWEB https:// www.osti.gov/etdeweb/biblio/20485411 (accessed December 17, 2018). (25) Mohseni, P.; Hahn, N. A.; Frank, R. A.; Hewitt, L. M.; Hajibabaei, M.; Van Der Kraak, G. Naphthenic Acid Mixtures from Oil Sands Process-Affected Water Enhance Differentiation of Mouse

James L. Stafford: 0000-0002-3551-2909 Mohamed Gamal El-Din: 0000-0001-6869-1459 Notes

The authors declare no competing financial interest.

■

ACKNOWLEDGMENTS This research was supported by a research grant from the Natural Sciences and Engineering Research Council of Canada (NSERC) Senior Industrial Research Chair (IRC) in Oil Sands Tailings Water Treatment through the support by Syncrude Canada Ltd., Suncor Energy Inc., Shell Canada, Canadian Natural Resources Ltd., Total E&P Canada Ltd., EPCOR Water Services, IOWC Technologies Inc., Alberta Innovates - Energy and Environment Solution, and Alberta Environment and Parks. We also acknowledge the financial support provided by the Helmholtz-Alberta Initiative (HAI) through the Alberta Environment and Parks’ Eco Trust Program as well as grants from Canada’s Oil Sands Innovation Alliance (COSIA) towards water quality analytical work and Alberta Innovates towards mammalian toxicological research work.

■

REFERENCES

(1) Shu, Z.; Li, C.; Belosevic, M.; Bolton, J. R.; Gamal El-Din, M. Application of a Solar UV/Chlorine Advanced Oxidation Process to Oil Sands Process-Affected Water Remediation. Environ. Sci. Technol. 2014, 48 (16), 9692−9701. (2) Zhang, K.; Wiseman, S.; Giesy, J. P.; Martin, J. W. Bioconcentration of Dissolved Organic Compounds from Oil Sands Process-Affected Water by Medaka (Oryzias Latipes): Importance of Partitioning to Phospholipids. Environ. Sci. Technol. 2016, 50 (12), 6574−6582. (3) Anderson, J. C.; Wiseman, S. B.; Wang, N.; Moustafa, A.; PerezEstrada, L.; Gamal El-Din, M.; Martin, J. W.; Liber, K.; Giesy, J. P. Effectiveness of Ozonation Treatment in Eliminating Toxicity of Oil Sands Process-Affected Water to Chironomus Dilutus. Environ. Sci. Technol. 2012, 46 (1), 486−493. (4) Garcia-Garcia, E.; Ge, J. Q.; Oladiran, A.; Montgomery, B.; Gamal El-Din, M.; Perez-Estrada, L. C.; Stafford, J. L.; Martin, J. W.; Belosevic, M. Ozone Treatment Ameliorates Oil Sands Process Water Toxicity to the Mammalian Immune System. Water Res. 2011, 45 (18), 5849−5857. (5) Garcia-Garcia, E.; Pun, J.; Perez-Estrada, L. A.; Gamal El-Din, M.; Smith, D. W.; Martin, J. W.; Belosevic, M. Commercial Naphthenic Acids and the Organic Fraction of Oil Sands Process Water Downregulate Pro-Inflammatory Gene Expression and Macrophage Antimicrobial Responses. Toxicol. Lett. 2011, 203 (1), 62−73. (6) Martin, J. W.; Barri, T.; Han, X.; Fedorak, P. M.; Gamal El-Din, M.; Perez, L.; Scott, A. C.; Jiang, J. T. Ozonation of Oil Sands Process-Affected Water Accelerates Microbial Bioremediation. Environ. Sci. Technol. 2010, 44 (21), 8350−8356. (7) Pérez-Estrada, L. A.; Han, X.; Drzewicz, P.; Gamal El-Din, M.; Fedorak, P. M.; Martin, J. W. Structure−Reactivity of Naphthenic Acids in the Ozonation Process. Environ. Sci. Technol. 2011, 45 (17), 7431−7437. (8) Grewer, D. M.; Young, R. F.; Whittal, R. M.; Fedorak, P. M. Naphthenic Acids and Other Acid-Extractables in Water Samples from Alberta: What Is Being Measured? Sci. Total Environ. 2010, 408 (23), 5997−6010. (9) Kannel, P. R.; Gan, T. Y. Naphthenic Acids Degradation and Toxicity Mitigation in Tailings Wastewater Systems and Aquatic Environments: A Review. J. Environ. Sci. Health, Part A: Toxic/ Hazard. Subst. Environ. Eng. 2012, 47 (1), 1−21. (10) Rowland, S. J.; West, C. E.; Jones, D.; Scarlett, A. G.; Frank, R. A.; Hewitt, L. M. Steroidal Aromatic ‘Naphthenic Acids’ in Oil Sands 7092


Article

Environmental Science & Technology Embryonic Stem Cells and Affect Development of the Heart. Environ. Sci. Technol. 2015, 49 (16), 10165−10172. (26) Huang, R.; McPhedran, K. N.; Sun, N.; Chelme-Ayala, P.; Gamal El-Din, M. Investigation of the Impact of Organic Solvent Type and Solution PH on the Extraction Efficiency of Naphthenic Acids from Oil Sands Process-Affected Water. Chemosphere 2016, 146, 472−477. (27) Morandi, G. D.; Wiseman, S. B.; Pereira, A.; Mankidy, R.; Gault, I. G. M.; Martin, J. W.; Giesy, J. P. Effects-Directed Analysis of Dissolved Organic Compounds in Oil Sands Process-Affected Water. Environ. Sci. Technol. 2015, 49 (20), 12395−12404. (28) Huang, R.; Chen, Y.; Meshref, M. N. A.; Chelme-Ayala, P.; Dong, S.; Ibrahim, M. D.; Wang, C.; Klamerth, N.; Hughes, S. A.; Headley, J. V.; Peru, K. M. Characterization and Determination of Naphthenic Acids Species in Oil Sands Process-Affected Water and Groundwater from Oil Sands Development Area of Alberta, Canada. Water Res. 2018, 128, 129−137. (29) Hughes, S. A.; Huang, R.; Mahaffey, A.; Chelme-Ayala, P.; Klamerth, N.; Meshref, M. N. A.; Ibrahim, M. D.; Brown, C.; Peru, K. M.; Headley, J. V.; Gamal El-Din, M. Comparison of Methods for Determination of Total Oil Sands-Derived Naphthenic Acids in Water Samples. Chemosphere 2017, 187, 376−384. (30) Hagen, M. O.; Garcia-Garcia, E.; Oladiran, A.; Karpman, M.; Mitchell, S.; Gamal El-Din, M.; Martin, J. W.; Belosevic, M. The Acute and Sub-Chronic Exposures of Goldfish to Naphthenic Acids Induce Different Host Defense Responses. Aquat. Toxicol. 2012, 109, 143−149. (31) Allen, E. W. Process Water Treatment in Canada’s Oil Sands Industry: I. Target Pollutants and Treatment Objectives. J. Environ. Eng. Sci. 2008, 7 (2), 123−138. (32) Chung, E.; Yeung, F.; Leinwand, L. A. Akt and MAPK Signaling Mediate Pregnancy-Induced Cardiac Adaptation. J. Appl. Physiol. 2012, 112 (9), 1564−1575. (33) Mao, G.; Wang, J.; Kang, Y.; Tai, P.; Wen, J.; Zou, Q.; Li, G.; Ouyang, H.; Xia, G.; Wang, B. Progesterone Increases Systemic and Local Uterine Proportions of CD4+CD25+ Treg Cells during Midterm Pregnancy in Mice. Endocrinology 2010, 151 (11), 5477− 5488. (34) Bole-Feysot, C.; Goffin, V.; Edery, M.; Binart, N.; Kelly, P. A. Prolactin (PRL) and Its Receptor: Actions, Signal Transduction Pathways and Phenotypes Observed in PRL Receptor Knockout Mice. Endocr. Rev. 1998, 19 (3), 225−268. (35) Grattan, D. R.; Kokay, I. C. Prolactin: A Pleiotropic Neuroendocrine Hormone. J. Neuroendocrinol. 2008, 20 (6), 752− 763. (36) Nagaishi, V. S.; Cardinali, L. I.; Zampieri, T. T.; Furigo, I. C.; Metzger, M.; Donato, J. Possible Crosstalk between Leptin and Prolactin during Pregnancy. Neuroscience 2014, 259, 71−83. (37) Sykes, L.; MacIntyre, D. A.; Yap, X. J.; Teoh, T. G.; Bennett, P. R. The Th1:Th2 Dichotomy of Pregnancy and Preterm Labour https://www.hindawi.com/journals/mi/2012/967629/abs/ (accessed December 17, 2018). (38) Saito, S.; Fukunaga, R.; Ichijo, M.; Nagata, S. Expression of Granulocyte Colony-Stimulating Factor and Its Receptor at the Fetomaternal Interface in Murine and Human Pregnancy. Growth Factors 1994, 10 (2), 135−143. (39) Litwin, S.; Lagadari, M.; Barrientos, G.; Roux, M. E.; Margni, R.; Miranda, S. Comparative Immunohistochemical Study of M-CSF and G-CSF in Feto−Maternal Interface in a Multiparity Mouse Model. Am. J. Reprod. Immunol. Microbiol. 2005, 54 (5), 311−320. (40) Gagné, F.; André, C.; Turcotte, P.; Gagnon, C.; Sherry, J.; Talbot, A. A Comparative Toxicogenomic Investigation of Oil Sand Water and Processed Water in Rainbow Trout Hepatocytes. Arch. Environ. Contam. Toxicol. 2013, 65 (2), 309−323. (41) Gagné, F.; André, C.; Douville, M.; Talbot, A.; Parrott, J.; McMaster, M.; Hewitt, M. An Examination of the Toxic Properties of Water Extracts in the Vicinity of an Oil Sand Extraction Site. J. Environ. Monit. 2011, 13 (11), 3075−3086.

(42) Wang, J.; Cao, X.; Sun, J.; Huang, Y.; Tang, X. Disruption of Endocrine Function in H295R Cell in Vitro and in Zebrafish in Vivo by Naphthenic Acids. J. Hazard. Mater. 2015, 299, 1−9. (43) van den Heuvel, M. R.; Power, M.; Richards, J.; MacKinnon, M.; Dixon, D. G. Disease and Gill Lesions in Yellow Perch (Perca Flavescens) Exposed to Oil Sands Mining-Associated Waters. Ecotoxicol. Environ. Saf. 2000, 46 (3), 334−341. (44) Gentes, M.-L.; Whitworth, T. L.; Waldner, C.; Fenton, H.; Smits, J. E. Tree Swallows (Tachycineta Bicolor) Nesting on Wetlands Impacted by Oil Sands Mining Are Highly Parasitized by the Bird Blow Fly Protocalliphora Spp. J. Wildl. Dis. 2007, 43 (2), 167−178. (45) Sykes, L.; MacIntyre, D. A.; Yap, X. J.; Ponnampalam, S.; Teoh, T. G.; Bennett, P. R. Changes in the Th1: Th2 Cytokine Bias in Pregnancy and the Effects of the Anti-Inflammatory Cyclopentenone Prostaglandin 15-Deoxy--Prostaglandin https://www.hindawi.com/ journals/mi/2012/416739/abs/ (accessed December 17, 2018). (46) Mor, G.; Cardenas, I.; Abrahams, V.; Guller, S. Inflammation and Pregnancy: The Role of the Immune System at the Implantation Site. Ann. N. Y. Acad. Sci. 2011, 1221 (1), 80−87. (47) Cardenas, I.; Means, R. E.; Aldo, P.; Koga, K.; Lang, S. M.; Booth, C.; Manzur, A.; Oyarzun, E.; Romero, R.; Mor, G. Viral Infection of the Placenta Leads to Fetal Inflammation and Sensitization to Bacterial Products Predisposing to Preterm Labor. J. Immunol. 2010, 185, 1000289. (48) Mor, G.; Cardenas, I. REVIEW ARTICLE: The Immune System in Pregnancy: A Unique Complexity. Am. J. Reprod. Immunol. 2010, 63 (6), 425−433. (49) Huber, S. A.; Kupperman, J.; Newell, M. K. Estradiol Prevents and Testosterone Promotes Fas-Dependent Apoptosis in CD4+ Th2 Cells by Altering Bcl 2 Expression. Lupus 1999, 8 (5), 384−387. (50) Piccinni, M. P.; Giudizi, M. G.; Biagiotti, R.; Beloni, L.; Giannarini, L.; Sampognaro, S.; Parronchi, P.; Manetti, R.; Annunziato, F.; Livi, C. Progesterone Favors the Development of Human T Helper Cells Producing Th2-Type Cytokines and Promotes Both IL-4 Production and Membrane CD30 Expression in Established Th1 Cell Clones. J. Immunol. 1995, 155 (1), 128−133. (51) Garratt, M.; Vasilaki, A.; Stockley, P.; McArdle, F.; Jackson, M.; Hurst, J. L. Is Oxidative Stress a Physiological Cost of Reproduction? An Experimental Test in House Mice. Proc. R. Soc. London, Ser. B 2011, 278 (1708), 1098−1106. (52) Fuzzen, M.; Bernier, N.; Van Der Kraak, G. Hormones and Reproduction of Vertebrates, Volume 3 - 1st Edition https://www. elsevier.com/books/hormones-and-reproduction-of-vertebratesvolume-3/norris/978-0-12-374930-7 (accessed December 17, 2018). (53) Xu, Y.-C.; Yang, D.-B.; Speakman, J. R.; Wang, D.-H. Oxidative Stress in Response to Natural and Experimentally Elevated Reproductive Effort Is Tissue Dependent. Funct. Ecol. 2014, 28 (2), 402−410. (54) Zheng, G.-X.; Lin, J.-T.; Zheng, W.-H.; Cao, J.; Zhao, Z.-J. Energy Intake, Oxidative Stress and Antioxidant in Mice during Lactation. Zool. Res. 2015, 36 (2), 95−102. (55) Metcalfe, N. B.; Alonso-Alvarez, C. Oxidative Stress as a LifeHistory Constraint: The Role of Reactive Oxygen Species in Shaping Phenotypes from Conception to Death. Funct. Ecol. 2010, 24 (5), 984−996. (56) Monaghan, P.; Metcalfe, N. B.; Torres, R. Oxidative Stress as a Mediator of Life History Trade-Offs: Mechanisms, Measurements and Interpretation. Ecol. Lett. 2009, 12 (1), 75−92. (57) Agarwal, A.; Aponte-Mellado, A.; Premkumar, B. J.; Shaman, A.; Gupta, S. The Effects of Oxidative Stress on Female Reproduction: A Review. Reprod. Biol. Endocrinol. 2012, 10 (1), 49. (58) Webster, R. P.; Roberts, V. H. J.; Myatt, L. Protein Nitration in Placenta − Functional Significance. Placenta 2008, 29 (12), 985−994. (59) Dennery, P. A. Effects of Oxidative Stress on Embryonic Development. Birth Defects Res., Part C 2007, 81 (3), 155−162. (60) Gagné, F.; Douville, M.; André, C.; Debenest, T.; Talbot, A.; Sherry, J.; Hewitt, L. M.; Frank, R. A.; McMaster, M. E.; Parrott, J.; Bickerton, G. Differential Changes in Gene Expression in Rainbow 7093


Article

Environmental Science & Technology Trout Hepatocytes Exposed to Extracts of Oil Sands Process-Affected Water and the Athabasca River. Comp. Biochem. Physiol., Part C: Toxicol. Pharmacol. 2012, 155 (4), 551−559. (61) Paul, C.; Teng, S.; Saunders, P. T. K. A Single, Mild, Transient Scrotal Heat Stress Causes Hypoxia and Oxidative Stress in Mouse Testes, Which Induces Germ Cell Death. Biol. Reprod. 2009, 80 (5), 913−919. (62) Byington, K. H.; Hansbrough, E. Inhibition of the Enzymatic Activity of Ligandin by Organogermanium, Organolead or Organotin Compounds and the Biliary Excretion of Sulfobromophthalein by the Rat. J. Pharmacol. Exp. Ther. 1979, 208 (2), 248−253. (63) Speakman, J. R.; Garratt, M. Oxidative Stress as a Cost of Reproduction: Beyond the Simplistic Trade-off Model. BioEssays 2014, 36 (1), 93−106. (64) Jackson, S. P.; Bartek, J. The DNA-Damage Response in Human Biology and Disease. Nature 2009, 461 (7267), 1071−1078. (65) Sampath, H.; Vartanian, V.; Rollins, M. R.; Sakumi, K.; Nakabeppu, Y.; Lloyd, R. S. 8-Oxoguanine DNA Glycosylase (OGG1) Deficiency Increases Susceptibility to Obesity and Metabolic Dysfunction. PLoS One 2012, 7 (12), No. e51697.

7094


Exposure to Organic Fraction Extracted from Oil Sands Process

Recommend Documents