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Wang X, Rowan-Carroll A, Meier MJ, Yauk CL, Wade MG, Robaire B, Hales BF. House dust-derived mixtures of organophosphate esters alter the phenotype, function, transcriptome, and lipidome of KGN human ovarian granulosa cells. Toxicol Sci 2024; 200:95-113. [PMID: 38603619 PMCID: PMC11199920 DOI: 10.1093/toxsci/kfae052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2024] Open
Abstract
Organophosphate esters (OPEs), used as flame retardants and plasticizers, are present ubiquitously in the environment. Previous studies suggest that exposure to OPEs is detrimental to female fertility in humans. However, no experimental information is available on the effects of OPE mixtures on ovarian granulosa cells, which play essential roles in female reproduction. We used high-content imaging to investigate the effects of environmentally relevant OPE mixtures on KGN human granulosa cell phenotypes. Perturbations to steroidogenesis were assessed using ELISA and qRT-PCR. A high-throughput transcriptomic approach, TempO-Seq, was used to identify transcriptional changes in a targeted panel of genes. Effects on lipid homeostasis were explored using a cholesterol assay and global lipidomic profiling. OPE mixtures altered multiple phenotypic features of KGN cells, with triaryl OPEs in the mixture showing higher potencies than other mixture components. The mixtures increased basal production of steroid hormones; this was mediated by significant changes in the expression of critical transcripts involved in steroidogenesis. Further, the total-OPE mixture disrupted cholesterol homeostasis and the composition of intracellular lipid droplets. Exposure to complex mixtures of OPEs, similar to those found in house dust, may adversely affect female reproductive health by altering a multitude of phenotypic and functional endpoints in granulosa cells. This study provides novel insights into the mechanisms of actions underlying the toxicity induced by OPEs and highlights the need to examine the effects of human relevant chemical mixtures.
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Affiliation(s)
- Xiaotong Wang
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Quebec, H3G 1Y6, Canada
| | - Andrea Rowan-Carroll
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, K1A 0K9, Canada
| | - Matthew J Meier
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, K1A 0K9, Canada
| | - Carole L Yauk
- Department of Biology, University of Ottawa, Ottawa, Ontario, K1N 9A7, Canada
| | - Michael G Wade
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, K1A 0K9, Canada
| | - Bernard Robaire
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Quebec, H3G 1Y6, Canada
- Department of Obstetrics and Gynecology, McGill University, Montréal, Quebec, H3G 1Y6, Canada
| | - Barbara F Hales
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Quebec, H3G 1Y6, Canada
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2
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Li J, Wu YJ. Tri-ortho-cresyl phosphate induces hepatic steatosis by mTOR activation and ER stress induction. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 271:116010. [PMID: 38280340 DOI: 10.1016/j.ecoenv.2024.116010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 12/17/2023] [Accepted: 01/21/2024] [Indexed: 01/29/2024]
Abstract
Tri-ortho-cresyl phosphate (TOCP), an organophosphorus compound (OP), which is widely used as plasticizer, flame retardant and other industrial products, has been reported to cause multiple toxicities including neurotoxicity and reproductive toxicity. However, it remains to be elusive whether TOCP induces hepatotoxicity. The purpose of this study was to investigate the effect of TOCP on hepatocytes and the lipid metabolism in particular. The adult mice were given a single dose of TOCP (800 mg/kg, p.o.) and the histological changes in liver tissue and lipid content in serum were determined. The results showed that more vacuoles and lipid droplets were observed in the liver of the mice exposed to TOCP. And triglyceride concentrations in serum and liver tissue significantly increased. However, the histopathological changes of the liver and the elevated triglyceride levels in the exposed mice can be reversed by endoplasmic reticulum (ER) stress inhibitor 4-phenylbutyric acid and mTOR signal inhibitor rapamycin. It was also found that the changes of expression levels of the biomarkers of ER stress and mTOR signaling pathway, such as GRP78, CHOP, and p-mTOR, in the exposed mice were consistent with those observed in the cultured primary hepatocytes treated with the same chemicals. These results showed that TOCP activated mTOR signal and ER stress to induce de novo lipid synthesis, which led to the hepatic steatosis in mouse.
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Affiliation(s)
- Jing Li
- Laboratory of Molecular Toxicology, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yi-Jun Wu
- Laboratory of Molecular Toxicology, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
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Wang X, Rowan-Carroll A, Meier MJ, Williams A, Yauk CL, Hales BF, Robaire B. Toxicological Mechanisms and Potencies of Organophosphate Esters in KGN Human Ovarian Granulosa Cells as Revealed by High-throughput Transcriptomics. Toxicol Sci 2023; 197:kfad114. [PMID: 37941476 PMCID: PMC10823774 DOI: 10.1093/toxsci/kfad114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2023] Open
Abstract
Despite the growing number of studies reporting potential risks associated with exposure to organophosphate esters (OPEs), their molecular mechanisms of action remain poorly defined. We used the high-throughput TempO-Seq™ platform to investigate the effects of frequently detected OPEs on the expression of ∼3000 environmentally responsive genes in KGN human ovarian granulosa cells. Cells were exposed for 48 h to one of five OPEs (0.1 to 50 μM): tris(methylphenyl) phosphate (TMPP), isopropylated triphenyl phosphate (IPPP), tert-butylphenyl diphenyl phosphate (BPDP), triphenyl phosphate (TPHP), or tris(2-butoxyethyl) phosphate (TBOEP). The sequencing data indicate that four OPEs induced transcriptional changes, whereas TBOEP had no effect within the concentration range tested. Multiple pathway databases were used to predict alterations in biological processes based on differentially expressed genes. At lower concentrations, inhibition of the cholesterol biosynthetic pathway was the predominant effect of OPEs; this was likely a consequence of intracellular cholesterol accumulation. At higher concentrations, BPDP and TPHP had distinct effects, primarily affecting pathways involved in cell cycle progression and other stress responses. Benchmark concentration (BMC) modelling revealed that BPDP had the lowest transcriptomic point of departure. However, in vitro to in vivo extrapolation modeling indicated that TMPP was bioactive at lower concentrations than the other OPEs. We conclude that these new approach methodologies provide information on the mechanism(s) underlying the effects of data-poor compounds and assist in the derivation of protective points of departure for use in chemical read-across and decision-making.
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Affiliation(s)
- Xiaotong Wang
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada
| | - Andrea Rowan-Carroll
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario K2K 0K9, Canada
| | - Matthew J Meier
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario K2K 0K9, Canada
| | - Andrew Williams
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario K2K 0K9, Canada
| | - Carole L Yauk
- Department of Biology, University of Ottawa, Ottawa, Ontario K1N 9A7, Canada
| | - Barbara F Hales
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada
| | - Bernard Robaire
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada
- Department of Obstetrics and Gynecology, McGill University, Montréal, Québec H3G 1Y6, Canada
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Liu Y, Li Y, Xiao N, Liu M, Wang Y, Luo H, Yao Y, Feng Y, Wang S. Serum Organophosphate Flame retardants and plasticizers in Chinese females of childbearing age: Association with serum reproductive and thyroid hormones. CHEMOSPHERE 2023:139237. [PMID: 37331665 DOI: 10.1016/j.chemosphere.2023.139237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 06/13/2023] [Accepted: 06/14/2023] [Indexed: 06/20/2023]
Abstract
Organophosphate flame retardants (OPFRs) are extensively used as flame retardants and plasticizers, but their endocrine disrupting potentials have raised concerns. However, the impacts of OPFR exposures on reproductive and thyroid hormones in females remains unclear. In this study, serum concentrations of OPFRs were investigated, and levels of reproductive and thyroid hormones, including follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol, anti-Müllerian hormone, prolactin (PRL), testosterone (T), and thyroid stimulating hormone, were analyzed in childbearing-age females undergoing in-vitro fertilization treatment from Tianjin, a coastal city in China (n = 319). Tris (2-chloroethyl) phosphate (TCEP) was the predominant OPFR, with a median concentration of 0.33 ng/mL and a detection frequency of 96.6%. In the whole population, tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) and tris(2-chloroisopropyl) phosphate (TCIPP) were positively associated with T (p < 0.05), while triethyl phosphate (TEP) was negatively associated with LH (p < 0.05) and LH/FSH (p < 0.01). Particularly, TCIPP was negatively associated with PRL in the younger subgroup (age≤30, p < 0.05). Moreover, TCIPP was negatively associated with diagnostic antral follicle counting (AFC) in the mediation analysis by a dominating direct effect (p < 0.01). In conclusion, serum levels of OPFRs were significantly associated with reproductive and thyroid hormone levels and a risk of decreased ovarian reserve in childbearing-age females, with age and body mass index being significant influencing factors.
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Affiliation(s)
- Yarui Liu
- College of Environmental Science and Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin, 300350, China; School of Environmental Science and Engineering, Academy of Environment and Ecology, Tianjin University, 92 Weijin Road, Nankai District, Tianjin, 300072, China.
| | - Yongcheng Li
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin, 300350, China.
| | - Nan Xiao
- Department of Center for Reproductive Medicine, Tianjin Central Hospital of Gynecology Obstetrics / Tianjin Key Laboratory of Human Development and Reproductive Regulation, 156 Nankaisanma Road, Nankai District, Tianjin, 300100, China.
| | - Min Liu
- Department of Center for Reproductive Medicine, Tianjin Central Hospital of Gynecology Obstetrics / Tianjin Key Laboratory of Human Development and Reproductive Regulation, 156 Nankaisanma Road, Nankai District, Tianjin, 300100, China.
| | - Yu Wang
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin, 300350, China.
| | - Haining Luo
- Department of Center for Reproductive Medicine, Tianjin Central Hospital of Gynecology Obstetrics / Tianjin Key Laboratory of Human Development and Reproductive Regulation, 156 Nankaisanma Road, Nankai District, Tianjin, 300100, China.
| | - Yiming Yao
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin, 300350, China.
| | - Yujie Feng
- School of Environmental Science and Engineering, Academy of Environment and Ecology, Tianjin University, 92 Weijin Road, Nankai District, Tianjin, 300072, China; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No. 73 Huanghe Road, Nangang District, Harbin, 150090, China.
| | - Shuo Wang
- College of Environmental Science and Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin, 300350, China; Tianjin Key Laboratory of Food Science and Health, School of Medicine, Nankai University, 94 Weijin Road, Nankai District, Tianjin, 300071, China.
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5
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Land KL, Miller FG, Fugate AC, Hannon PR. The effects of endocrine-disrupting chemicals on ovarian- and ovulation-related fertility outcomes. Mol Reprod Dev 2022; 89:608-631. [PMID: 36580349 PMCID: PMC10100123 DOI: 10.1002/mrd.23652] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 11/03/2022] [Accepted: 11/06/2022] [Indexed: 11/21/2022]
Abstract
Exposure to endocrine-disrupting chemicals (EDCs) is unavoidable, which represents a public health concern given the ability of EDCs to target the ovary. However, there is a large gap in the knowledge about the impact of EDCs on ovarian function, including the process of ovulation. Defects in ovulation are the leading cause of infertility in women, and EDC exposures are contributing to the prevalence of infertility. Thus, investigating the effects of EDCs on the ovary and ovulation is an emerging area for research and is the focus of this review. The effects of EDCs on gametogenesis, uterine function, embryonic development, and other aspects of fertility are not addressed to focus on ovarian- and ovulation-related fertility issues. Herein, findings from epidemiological and basic science studies are summarized for several EDCs, including phthalates, bisphenols, per- and poly-fluoroalkyl substances, flame retardants, parabens, and triclosan. Epidemiological literature suggests that exposure is associated with impaired fecundity and in vitro fertilization outcomes (decreased egg yield, pregnancies, and births), while basic science literature reports altered ovarian follicle and corpora lutea numbers, altered hormone levels, and impaired ovulatory processes. Future directions include identification of the mechanisms by which EDCs disrupt ovulation leading to infertility, especially in women.
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Affiliation(s)
- Katie L. Land
- Department of Obstetrics & Gynecology, College of MedicineUniversity of KentuckyLexingtonKentuckyUSA
| | - Frances G. Miller
- Department of Obstetrics & Gynecology, College of MedicineUniversity of KentuckyLexingtonKentuckyUSA
| | - Ava C. Fugate
- Department of Obstetrics & Gynecology, College of MedicineUniversity of KentuckyLexingtonKentuckyUSA
| | - Patrick R. Hannon
- Department of Obstetrics & Gynecology, College of MedicineUniversity of KentuckyLexingtonKentuckyUSA
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Wang X, Luu T, Beal MA, Barton-Maclaren TS, Robaire B, Hales BF. The Effects of Organophosphate Esters Used as Flame Retardants and Plasticizers on Granulosa, Leydig, and Spermatogonial Cells Analyzed Using High-Content Imaging. Toxicol Sci 2022; 186:269-287. [PMID: 35135005 PMCID: PMC8963303 DOI: 10.1093/toxsci/kfac012] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The replacement of regulated brominated flame retardants and plasticizers with organophosphate esters (OPEs) has led to their pervasive presence in the environment and in biological matrices. Further, there is evidence that exposure to some of these chemicals is associated with reproductive toxicity. Using a high-content imaging approach, we assessed the effects of exposure to 9 OPEs on cells related to reproductive function: KGN human granulosa cells, MA-10 mouse Leydig cells, and C18-4 mouse spermatogonial cells. The effects of OPEs were compared with those of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), a legacy brominated flame retardant. Alterations in several important cell features, including cell survival, mitochondrial dynamics, oxidative stress, lysosomes, and lipid droplets, were analyzed. Most of the OPEs tested displayed higher cytotoxicity than BDE-47 in all 3 cell lines. Effects on phenotypic parameters were specific for each cell type. Several OPEs increased total mitochondria, decreased lysosomes, increased the total area of lipid droplets, and induced oxidative stress in KGN cells; these endpoints were differentially affected in MA-10 and C18-4 cells. Alterations in cell phenotypes were highly correlated in the 2 steroidogenic cell lines for a few triaryl OPEs. Potency ranking using 2 complementary approaches, Toxicological Prioritization Index analyses and the lowest benchmark concentration/administered equivalent dose method, revealed that while most of the OPEs tested were more potent than BDE-47, others showed little to no effect. We propose that these approaches serve as lines of evidence in a screening strategy to identify the potential for reproductive and endocrine effects of emerging chemicals and assist in regulatory decision-making.
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Affiliation(s)
- Xiaotong Wang
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Trang Luu
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Marc A Beal
- Existing Substances Risk Assessment Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario K1A 0K9, Canada
| | - Tara S Barton-Maclaren
- Existing Substances Risk Assessment Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario K1A 0K9, Canada
| | - Bernard Robaire
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec H3G 1Y6, Canada,Department of Obstetrics & Gynecology, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Barbara F Hales
- To whom correspondence should be addressed at Department of Pharmacology & Therapeutics, McGill University, 3655 Promenade Sir William Osler, Room 110, Montreal, QC H3G1Y6, Canada. E-mail:
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7
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Li J, Qin Q, Li YX, Leng XF, Wu YJ. Tri-ortho-cresyl phosphate exposure leads to low egg production and poor eggshell quality via disrupting follicular development and shell gland function in laying hens. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 225:112771. [PMID: 34530258 DOI: 10.1016/j.ecoenv.2021.112771] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 09/07/2021] [Accepted: 09/08/2021] [Indexed: 06/13/2023]
Abstract
Tri-ortho-cresyl phosphate (TOCP) has been used commercially as a plasticizer and a flame retardant, which has been reported to cause multiple toxicities in humans and other animals. However, the effect of TOCP on female reproductive system is still unclear. The aim of this investigation was to evaluate the reproductive toxicity of TOCP in female avian and investigate its molecular mechanism. In the current study, 50 adult hens were given a single oral dose of TOCP (750 mg/kg). Egg laid by the hens were harvested and counted. Egg quality is assessed by determining the shell strength and thickness. Samples of ovary, shell gland, and serum were collected on day 0, 2, 7, and 21 after the administration. The morphological and pathological changes in tissues were examined. Cell death, follicular development, and steroidogenesis were determined to assess the toxicity of TOCP on laying hens. The results showed that egg production, egg weight, and eggshell strength significantly decreased after TOCP exposure. The calcium levels in serum and eggshell decreased and the expression levels of the eggshell formation-related genes calbindin-D28k (CaBP-D28k) and carbonic anhydrase 2 (CA2) were downregulated. The inhibitory effects of TOCP on follicular development and steroidogenesis were observed with changes in the levels of the related proteins such as forkhead box O1 (FoxO1) and mothers against decapentaplegic homolog 2/3 (Smad2/3). Cell death was identified, which might lead to follicular development disorder. Taken together, TOCP reduced the quantity and quality of the eggs laid by the hens through disrupting follicular development, steroidogenesis, and shell gland function.
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Affiliation(s)
- Jing Li
- Laboratory of Molecular Toxicology, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qilian Qin
- Group of Insect Virology, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yu-Xia Li
- Laboratory of Molecular Toxicology, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xin-Fu Leng
- Laboratory of Molecular Toxicology, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yi-Jun Wu
- Laboratory of Molecular Toxicology, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
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Wang X, Hales BF, Robaire B. Effects of flame retardants on ovarian function. Reprod Toxicol 2021; 102:10-23. [PMID: 33819575 DOI: 10.1016/j.reprotox.2021.03.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 03/10/2021] [Accepted: 03/23/2021] [Indexed: 02/07/2023]
Abstract
Flame retardants have been added to a variety of consumer products and are now found ubiquitously throughout the environment. Epidemiological, in vivo, and in vitro studies have shown that polybrominated diphenyl ether (PBDE) flame retardants may have a negative impact on human health; this has resulted in their phase-out and replacement by alternative flame retardants, such as hexabromocyclododecane (HBCDD), tetrabromobisphenol A (TBBPA), and organophosphate esters (OPEs). Evidence suggests that some of these chemicals induce ovarian dysfunction and thus may be detrimental to female fertility; however, the effects of many of these flame retardants on the ovary remain unclear. In this review, we present an overview of the effects of brominated and organophosphate ester flame retardants on ovarian function and discuss the possible mechanisms which may mediate these effects.
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Affiliation(s)
- Xiaotong Wang
- Departments of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Barbara F Hales
- Departments of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Bernard Robaire
- Departments of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada; Obstetrics and Gynecology, McGill University, Montreal, Quebec, Canada.
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Yan H, Hales BF. Effects of an Environmentally Relevant Mixture of Organophosphate Esters Derived From House Dust on Endochondral Ossification in Murine Limb Bud Cultures. Toxicol Sci 2021; 180:62-75. [PMID: 33367866 PMCID: PMC7916738 DOI: 10.1093/toxsci/kfaa180] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Organophosphate esters (OPEs) are used widely as flame retardants and plasticizers but much remains unknown about their potential toxicity. Previously, we reported that 4 individual OPEs suppress endochondral ossification in murine limb bud cultures. However, real-life exposure is to complex OPE mixtures. In the present study, we tested the hypothesis that a Canadian household dust-based OPE mixture will affect endochondral ossification in gestation day 13 CD1 mouse embryo limb buds expressing fluorescent markers for the major cell populations involved in the process: collagen type II alpha 1-enhanced cyan fluorescent protein (proliferative chondrocytes), collagen type X alpha 1-mCherry (hypertrophic chondrocytes), and collagen type I alpha 1-yellow fluorescent protein (osteoblasts). Limbs were cultured for 6 days in the presence of vehicle or dilutions of the OPE mixture (1/1 000 000, 1/600 000, and 1/300 000). All 3 OPE mixture dilutions affected cartilage template development and the progression of endochondral ossification, as indicated by the fluorescent markers. The expression of Sox9, the master regulator of chondrogenesis, was unchanged, but the expression of Runx2 and Sp7, which drive chondrocyte hypertrophy and osteoblastogenesis, was dilution-dependently suppressed. RNA-seq revealed that exposure to the 1/300 000 dilution of the OPE mixture for 24 h downregulated 153 transcripts and upregulated 48 others by at least 1.5-fold. Downregulated transcripts were enriched for those related to the immune system and bone formation. In contrast, upregulated transcripts were enriched for those with stress response functions known to be regulated by ATF4 activation. Thus, exposure to the mixture of OPEs commonly found in house dust may have adverse effects on bone formation.
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Affiliation(s)
- Han Yan
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Barbara F Hales
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec H3G 1Y6, Canada
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10
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Sibomana I, Mattie DR. Sub-chronic dermal exposure to aircraft engine oils impacts the reproductive organ weights and alters hematological profiles of Sprague Dawley rats. Curr Res Toxicol 2020; 1:12-24. [PMID: 34345833 PMCID: PMC8320628 DOI: 10.1016/j.crtox.2020.02.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 01/15/2020] [Accepted: 02/07/2020] [Indexed: 11/17/2022] Open
Abstract
There is little data available for the toxicity of used aircraft engine oils relative to their unused (new) versions. This study was conducted to determine if grade 3 (G3) and 4 (G4) aircraft engine oils in their new states (G3-N and G4-N) and their used versions (G3-U and G4-U) have the potential to induce toxicity via dermal application. Male and female Sprague Dawley rats were dermally exposed to water (control), new and used versions of G3 and G4 oils to determine the oil sub-chronic toxicity potentials. A volume of 300 μL of undiluted oil was applied to the pad of the Hill Top Chamber System©. Then the chamber was attached to a fur-free test site located at the back of the rat for 6 h/day for 5 consecutive days/week for 21 days (15 total exposures). Recovery rats also received similar treatments and were kept for 14 days post-exposure to screen for reversibility, persistence, or delayed occurrence of toxic effects. Both G3 and G4 oils had a significant impact on the weight of male and female reproductive organs: testes weights for recovery rats exposed to G3-N significantly decreased (12%) relative to controls; G3-N and G3-U decreased uterus weights by 23% and 29%, respectively; G4-N decreased uterus weights by 32% but were resolved at the end of the recovery period; G4-N increased the weight of the adrenals and spleen for females by 34% and 27%, respectively, during the recovery period. G3 and G4 induced more changes in female blood indices than in those for males. Of all versions of oils, G4-N induced the most changes in profiles of female blood. G4-N significantly decreased the white blood cells, lymphocytes, neutrophils, eosinophils and increased the mean platelet volumes. Interestingly, males were not affected by exposure to G4-N oil. While G3-N decreased the white blood cells and lymphocytes for females it slightly increased those for males. In summary, G3 and G4 oils impacted the weights for male and reproductive organs. This study highlights the health risks that aircraft maintenance workers may be exposed to if precautions are not taken to minimize exposure to these oils. Grade 3 and grade 4 aircraft engine oils contain organophosphate compounds. Dermal exposure to these oils impacted organ weights of female and male rats. Unused versions of these oils had more effects on blood indices than used versions. Females may be more susceptible to exposure to these oils than males.
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Key Words
- Aircraft engine oils
- BA, basophils
- Dermal exposure
- EO, eosinophils
- G3, grade 3
- G3-N, grade 3 in an unused state
- G3-U, grade 3 in a used state
- G4, grade 4
- G4-N, grade 4 in an unused state
- G4-U, grade 4 in a used state
- HCT, hematocrit
- Hematological parameters
- Hgb, hemoglobin
- IACUC, Institutional Animal Care and Use Committee
- LY, lymphocytes
- MCH, mean corpuscular hemoglobin
- MCHC, mean corpuscular hemoglobin concentration
- MCV, mean corpuscular volume
- MO, monocytes
- MPV, mean platelet volume
- NE, neutrophils
- NMR, nuclear magnetic resonance
- PLT, platelets
- RBC, red blood cells
- RDW, red blood cell distribution width
- Reproductive organs
- SDS, safety data sheet
- Sprague Dawley rats
- TCP, tricresyl phosphate
- TIPP, phenol isopropylated phosphate (3:1)
- TOCP, tri-ortho-cresyl phosphate
- TPP, triphenyl phosphate
- WBC, white blood cells
- WPAFB, Wright-Patterson Air Force Base
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Affiliation(s)
- Isaie Sibomana
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Air Force Research Laboratory, 711 HPW/RHBB, Wright-Patterson AFB, OH 45433, USA
- Air Force Research Laboratory, 711 Human Performance Wing, Airman Systems Directorate (AFRL/711 HPW/RHBB), Wright-Patterson AFB, OH 45433, USA
- Corresponding author at: Air Force Research Laboratory, 711 Human Performance Wing, Airman Systems Directorate (AFRL/711 HPW/RHBB), Wright-Patterson AFB, OH 45433, USA.
| | - David R. Mattie
- Air Force Research Laboratory, 711 Human Performance Wing, Airman Systems Directorate (AFRL/711 HPW/RHBB), Wright-Patterson AFB, OH 45433, USA
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11
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Yang B, Wang X, Ma Y, Yan L, Ren Y, Yu D, Qiao B, Shen X, Liu H, Zhang D, Kuang H. Tri-ortho-cresyl phosphate (TOCP)-induced reproductive toxicity involved in placental apoptosis, autophagy and oxidative stress in pregnant mice. ENVIRONMENTAL TOXICOLOGY 2020; 35:97-107. [PMID: 31566301 DOI: 10.1002/tox.22846] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 08/31/2019] [Accepted: 09/03/2019] [Indexed: 06/10/2023]
Abstract
Tri-ortho-cresyl phosphate (TOCP) has been widely used as plasticizers, and reported causing reproductive toxicity in mammals. However, little is known about the toxic effect on the placenta. In this study, dams were orally administered different doses of TOCP to explore the effect of TOCP on placental development. Results showed that TOCP exposure significantly reduced numbers of implanted embryo, caused atrophy and collapse of ectoplacental cone, and decreased total areas of placenta and numbers of PCNA-positive cells. Expression levels of placental development genes were prominently downregulated in the TOCP-treated groups. Moreover, TOCP administration induced placental apoptosis and autophagy by upregulating P53, Bax, Beclin-1, ratio of LC3 II/LC3 I and Atg5 and downregulating Bcl-2 protein. In addition, TOCP exposure markedly inhibited activities of catalase and superoxide dismutase and increased the production of H2 O2 and malondialdehyde. Collectively, these findings suggest that apoptosis, autophagy and oxidative stress may be involved in the TOCP-induced reproductive toxicity.
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Affiliation(s)
- Bei Yang
- Department of Physiology, Basic Medical College, Nanchang University, Nanchang, Jiangxi, PR China
| | - Xinlu Wang
- Department of Physiology, Basic Medical College, Nanchang University, Nanchang, Jiangxi, PR China
- Department of Clinic Medicine, School of Queen Mary, Nanchang University, Nanchang, Jiangxi, PR China
| | - Yilin Ma
- Department of Physiology, Basic Medical College, Nanchang University, Nanchang, Jiangxi, PR China
- Department of Clinic Medicine, School of Queen Mary, Nanchang University, Nanchang, Jiangxi, PR China
| | - Lei Yan
- Department of Physiology, Basic Medical College, Nanchang University, Nanchang, Jiangxi, PR China
| | - Yuan Ren
- Department of Physiology, Basic Medical College, Nanchang University, Nanchang, Jiangxi, PR China
| | - Dainan Yu
- Department of Physiology, Basic Medical College, Nanchang University, Nanchang, Jiangxi, PR China
| | - Bo Qiao
- Department of Physiology, Basic Medical College, Nanchang University, Nanchang, Jiangxi, PR China
| | - Xin Shen
- Department of Physiology, Basic Medical College, Nanchang University, Nanchang, Jiangxi, PR China
| | - Hui Liu
- Department of Physiology, Basic Medical College, Nanchang University, Nanchang, Jiangxi, PR China
| | - Dalei Zhang
- Department of Physiology, Basic Medical College, Nanchang University, Nanchang, Jiangxi, PR China
| | - Haibin Kuang
- Department of Physiology, Basic Medical College, Nanchang University, Nanchang, Jiangxi, PR China
- Jiangxi Provincial Key Laboratory of Reproductive Physiology and Pathology, Medical Experimental Teaching Center, Nanchang University, Nanchang, Jiangxi, PR China
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12
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Tri-ortho-cresyl phosphate (TOCP) induced ovarian failure in mice is related to the Hippo signaling pathway disruption. Reprod Toxicol 2019; 83:21-27. [DOI: 10.1016/j.reprotox.2018.10.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 09/27/2018] [Accepted: 10/13/2018] [Indexed: 01/25/2023]
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13
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Bhanot R, Sangha GK. Effect of in utero and lactational exposure of triazophos on reproductive system functions in male offsprings, Rattus norvegicus. Drug Chem Toxicol 2018; 42:519-525. [PMID: 29681207 DOI: 10.1080/01480545.2018.1457048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
In the present study, Triazophos (TZ) was used at acceptable daily intake (ADI) to investigate the consequence of prenatal and postnatal exposure on reproductive functions in the male offsprings. Pregnant females were divided into three groups, the first group was orally gavaged with olive oil (control), the second group was administered with 0.01 mg kg-1 bw of the ADI of TZ from gestation day (GD) 1 until parturition (designated as P group) and the third group was gavaged with the same dose from GD1 to postnatal day (PND) 21 of lactation (marked as P + L group). Non-significant reduction occurred in the body weight of pups except at (PND) 35 during which body weight of P + L group pups significantly decreased. Male offsprings born to TZ exposed females showed significant changes at maturity (PND 63) in weight of liver, thyroid and testis, alterations in the levels of protein, urea, creatinine in plasma and abnormal levels of cholesterol, phospholipids and lipid peroxidation in testicular homogenate. Gonadal inhibition in TZ exposed progeny was reflected from a significant fall in sperm count, sperm motility, plasma testosterone level and histopathological alterations in testis. Hence, in utero and lactational exposure to ADI level of TZ influences testis development and functions in the male offsprings. Further investigations are suggested with germline studies of offsprings to examine the transgenerational effect of TZ exposure.
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Affiliation(s)
- Reetu Bhanot
- a Department of Zoology, College of Basic Sciences and Humanities , Punjab Agricultural University , Ludhiana , India
| | - Gurinder Kaur Sangha
- a Department of Zoology, College of Basic Sciences and Humanities , Punjab Agricultural University , Ludhiana , India
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14
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Abstract
The 1CH (International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use) Guideline for Detection of Toxicity to Reproduction for Medicinal Products, adopted at the Second ICH Conference in Orlando, FL, U.S.A., emphasized the need for research into the suitability of various methods for the detection of effects on fertility in males. The current project was undertaken to compare the efficiency of methods by evaluating reports in the open literature. The results of the examination of 117 substances or substance classes support the view that histopathology and organ weight analysis provide the best general-purpose means of detecting substances with the potential to affect male fertility. Examinations at up to 4 weeks of treatment appear to be as effective as examinations conducted at later times. Mating with females for detection of effects unrelated to interference with sperm production appears to provide an optimal combination because adding other methodologies does not materially improve the detection rate. As to the timing of the mating trial, a 2-week premating period is as efficient as mating at 4 weeks and apparently more efficient than mating after prolonged premating treatment.
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Affiliation(s)
- Beate Ulbrich
- Federal Institute for Drugs and Medical Devices, Berlin, Germany; Huntingdon Research Centre, Huntingdon, Cambridgeshire, England
| | - Anthony K. Palmer
- Federal Institute for Drugs and Medical Devices, Berlin, Germany; Huntingdon Research Centre, Huntingdon, Cambridgeshire, England
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15
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Arukwe A, Carteny CC, Eggen T. Lipid peroxidation and oxidative stress responses in juvenile salmon exposed to waterborne levels of the organophosphate compounds tris(2-butoxyethyl)- and tris(2-chloroethyl) phosphates. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2016; 79:515-25. [PMID: 27484134 DOI: 10.1080/15287394.2016.1171978] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
There is limited knowledge on the toxicological, physiological, and molecular effects attributed to organophosphate (OP) compounds currently used as flame retardants or additives in consumer products. This study investigated the effects on oxidative stress and lipid peroxidation in juvenile Atlantic salmon liver and brain samples after exposure to two OP compounds, tris(2-butoxyethyl) phosphate (TBOEP) and tris(2-chloroethyl) phosphate (TCEP). In this study, groups of juvenile Atlantic salmon were exposed using a semistatic experimental protocol over a 7-d period to 3 different concentrations (0.04, 0.2, or 1 mg/L) of TBOEP and TCEP. When toxicological factors such as bioaccumulation and bioconcentration, and chemical structural characteristics and behavior, including absorption to solid materials, are considered, these concentrations represent environmentally relevant concentrations. The concentrations of the contaminants were derived from levels of their environmental occurrence. The expression of genes related to oxidative stress-glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST)-and to lipid peroxidation-peroxisome proliferator-activated receptors (PPAR)-were determined using quantitative (real-time) polymerase chain reaction (PCR). The presence of PPAR proteins was also investigated using immunochemical methods. Levels of thiobarbituric acid-reactive substances (TBARS) in liver were used as a measure of lipid peroxidation. Overall, our data show an increase in lipid peroxidation, and this was associated with an augmented expression of genes from the glutathione family of responses. Interestingly, PPAR expression in liver after exposure to TBOEP and TCEP was consistently decreased compared to controls, while expression in brain did not show a similar trend. The results suggest that OP contaminants may induce oxidative stress and thus production of reactive oxygen substances (ROS), and modulate lipid peroxidation processes in organisms.
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Affiliation(s)
- Augustine Arukwe
- a Department of Biology , Norwegian University of Science and Technology (NTNU) , Trondheim , Norway
| | - Camilla Catarci Carteny
- a Department of Biology , Norwegian University of Science and Technology (NTNU) , Trondheim , Norway
| | - Trine Eggen
- b Norwegian Institute of Bioeconomy Research (NIBIO), Ås , Norway
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16
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Abo-El-Soo K, Shalaby M, Hamoda A. Assessment of Toxicity of Chlorpyrifos Insecticide on Fetuses and Suckling Pups of Rats. ACTA ACUST UNITED AC 2013. [DOI: 10.5567/ecology-ik.2013.1.7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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17
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Yoshida T, Ikemi N, Takeuchi Y, Ebino K, Kojima S, Chiba Y, Nakashima N, Kawakatsu H, Saka M, Harada T. A repeated dose 90-day oral toxicity study of cyflumetofen,a novel acaricide, in rats. J Toxicol Sci 2012; 37:91-104. [DOI: 10.2131/jts.37.91] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
| | | | | | | | | | - Yuko Chiba
- The Institute of Environmental Toxicology
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18
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Schindler BK, Förster K, Angerer J. Determination of human urinary organophosphate flame retardant metabolites by solid-phase extraction and gas chromatography–tandem mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2009; 877:375-81. [DOI: 10.1016/j.jchromb.2008.12.030] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Revised: 12/10/2008] [Accepted: 12/14/2008] [Indexed: 10/21/2022]
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19
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Morgan AM, Abd El-Aty AM. Reproductive Toxicity Evaluation of Pestban Insecticide Exposure in Male and Female Rats. Toxicol Res 2008; 24:137-150. [PMID: 32038788 PMCID: PMC7006254 DOI: 10.5487/tr.2008.24.2.137] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2008] [Revised: 05/02/2008] [Accepted: 05/02/2008] [Indexed: 11/20/2022] Open
Abstract
Sexually mature male and female rats were orally intubated with the organophosphorus insecticide, Pestban at a daily dosage of 7.45 or 3.72 mg/kg bwt, equivalent to 1/20 and 1/40 LD50, respectively. Male rats were exposed for 70 days, while the female rats were exposed for 14 days, premating, during mating and throughout the whole length of gestation and lactation periods till weaning. The results showed depressed acetylcholinesterase (AChE) activity in the brain of parents, fetuses and their placentae in a dose-dependent manner. The fertility was significantly reduced with increasing the dose in both treated groups, with more pronounced suppressive effects in the male treated group. The number of implantation sites and viable fetuses were significantly reduced in pregnant females of both treated groups. However, the number of resorptions, dead fetuses, and pre-and postimplantation losses were significantly increased. The incidence of resorptions was more pronounced in treated female compared to male group and was dose dependant. The behavioral responses as well as fetal survival and viability indices were altered in both treated groups during the lactation period. The incidence of these effects was more pronounced in the treated female group and occurred in a dose-related manner. The recorded morphological, visceral, and skeletal anomalies were significantly increased with increasing the dose in fetuses of both treated groups, with more pronounced effects on fetuses of treated females. In conclusion, the exposure of adult male and female rats to Pestban would cause adverse effects on fertility and reproduction.
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Affiliation(s)
- Ashraf M. Morgan
- Department of Toxicology and Forensic Medicine; Faculty of Veterinary Medicine, Cairo University, 12211 Giza, Egypt
| | - A. M. Abd El-Aty
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Konkuk University, 1 Hwayang-dong, Kwangjin-gu, Seoul, 143-701 Korea
- Department of Pharmacology, Faculty of Veterinary Medicine, Cairo University, 12211 Giza, Egypt
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Honkakoski P, Palvimo JJ, Penttilä L, Vepsäläinen J, Auriola S. Effects of triaryl phosphates on mouse and human nuclear receptors. Biochem Pharmacol 2004; 67:97-106. [PMID: 14667932 DOI: 10.1016/j.bcp.2003.08.037] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The constitutively active receptor (CAR) is a crucial regulator of genes encoding for enzymes active in drug/steroid oxidation, conjugation, and transport. In our attempt to isolate the endogenous inhibitory ligand(s) for the mouse CAR, we found surprisingly that the inhibitory activity was associated with di- and tri-isopropylated phenyl phosphates that were present in livers of untreated mice. Trans-activation experiments in mammalian cells with synthetic compounds verified that mouse CAR was inhibited by various isopropylated phenyl phosphates (40-80%). Such triaryl phosphates are widely used as fire retardants, lubricants, and plasticizers, and some of them are known to disturb reproduction by currently unknown mechanisms. Equipped with the finding that these compounds could interact with mouse CAR, we proceeded to determine their functional effects on other nuclear receptors. Human CAR and pregnane X receptor (PXR) were variably activated (2-5-fold) by triaryl phosphates while mouse PXR, peroxisome proliferator-activated receptor-alpha, and vitamin D receptor were refractory. Among steroid hormone receptors, the human androgen receptor was inhibited by triphenyl phosphate and di-ortho-isopropylated phenyl phosphate (40-50%) and activated by di- and tri-para-substituted phenyl phosphates (2-fold). Our results add to the list of CAR and PXR activators and suggest steroid-dependent biological pathways that may contribute to the reproductive effects of triaryl phosphates.
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Affiliation(s)
- Paavo Honkakoski
- Department of Pharmaceutics, University of Kuopio, P.O. Box 1627, FIN-70211, Kuopio, Finland.
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21
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Chapin RE, Phelps JL, Burka LT, Abou-Donia MB, Heindel JJ. The effects of tri-o-cresyl phosphate and metabolites on rat Sertoli cell function in primary culture. Toxicol Appl Pharmacol 1991; 108:194-204. [PMID: 1902005 DOI: 10.1016/0041-008x(91)90110-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A neurotoxic organophosphate, tri-o-cresyl phosphate (TOCP) is also a testicular toxicant. Histopathologic damage in the testis is first seen in Sertoli cells. TOCP and its activated metabolite saligenin cyclic-o-tolyl phosphate (SCOTP) were evaluated for effects on rat Sertoli cells in primary culture. SCOTP, but not TOCP, caused minor morphologic effects on the cells and increased levels of lactate in the spent medium with no change in pyruvate levels, synthesis of cellular or secreted proteins, or the cyclic AMP response to FSH stimulation. SCOTP was the metabolite of TOCP that produced the largest decrease in nonspecific esterase activity in Sertoli cells (up to 80%), when tested in the concentration range found in vivo. This decrease is consistent with previous in vivo evidence. These in vitro experiments replicate previously observed in vivo biochemical effects and suggest that SCOTP is the metabolite responsible for at least some of the biochemical effects seen in the testis after TOCP exposure.
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Affiliation(s)
- R E Chapin
- Developmental and Reproductive Toxicology Group, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
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Chapin RE, Phelps JL, Somkuti SG, Heindel JJ, Burka LT. The interaction of Sertoli and Leydig cells in the testicular toxicity of tri-o-cresyl phosphate. Toxicol Appl Pharmacol 1990; 104:483-95. [PMID: 2385838 DOI: 10.1016/0041-008x(90)90170-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Previous studies have shown that after dosing with tri-o-cresyl phosphate (TOCP), the testis contains more active intermediate (saligenin cyclic-o-tolyl phosphate; SCOTP) than do other organs or blood. SCOTP is produced by a cytochrome P450-dependent reaction, and the Sertoli cells, although containing little P450, are the testicular cells that show the first signs of damage after TOCP administration. The present studies evaluated (i) whether testicular Leydig cell production of SCOTP might explain the elevated testicular concentration of SCOTP, (ii) if this production affected testosterone secretion, and (iii) if Sertoli cells cocultured over TOCP-exposed Leydig cells would show effects similar to those found after SCOTP exposure of Sertoli cells in vitro, indicating a cell interaction. Previous data showed that a target enzyme for SCOTP in Sertoli cells, nonspecific esterase (NSE), was inhibited by exposure in vitro to SCOTP, but not to TOCP. In the present experiments, HPLC analysis identified SCOTP in media from Leydig cells cultured with radiolabeled TOCP, demonstrating activation. TOCP addition to Leydig cells decreased testosterone output after stimulation with hCG, an effect that was replicated by subsequent in vivo experiments. Addition of various intermediates in the testosterone biosynthesis pathway indicated that both mitochondrial- and microsomal-based steps in the pathway were affected. Collectively, these data indicate that Leydig cells can activate TOCP. To model whether this activation might affect Sertoli cells in vivo, Sertoli cells were plated in culture-well inserts suspended above (cocultured with) isolated Leydig cells in the presence of TOCP. Sertoli NSE activity was diminished, while remaining unchanged when cultured in the presence of TOCP but without Leydig cells, or over Leydig cells alone. These results show that the Leydig cells in the testis are capable of activating TOCP to SCOTP, and that this can produce effects in Sertoli cells. This in situ activation of TOCP to SCOTP may help explain why the testis contains high concentrations of SCOTP after in vivo dosing with TOCP, and why the testis is a target organ for TOCP toxicity.
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Affiliation(s)
- R E Chapin
- Developmental and Reproductive Toxicology Group, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
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