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Guo Y, Liang C, Zeng MX, Wei GL, Zeng LX, Liu LY, Zeng EY. An overview of organophosphate esters and their metabolites in humans: Analytical methods, occurrence, and biomonitoring. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 848:157669. [PMID: 35926632 DOI: 10.1016/j.scitotenv.2022.157669] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 07/22/2022] [Accepted: 07/23/2022] [Indexed: 06/15/2023]
Abstract
With the strict regulation of brominated flame retardants, organophosphate esters (OPEs) have been extensively used as replacements. Increasing concerns on OPEs have aroused due to their extensive distribution in the environment and humans, as well as their potential toxicities. Recent studies have demonstrated that some organophosphate di-esters are even more toxic than their respective tri-esters. This review summarized the current state of knowledge on the analytical methodologies (including sample collection and preparation, instrumental analysis, and the feasibility of each potential human matrix), as well as the occurrences of OPEs and/or their metabolites (m-OPEs) in various human matrices. Organophosphate esters are readily metabolized in human thus only limited studies reported their occurrences in blood and breast milk, whereas abundant studies are available regarding the occurrences of m-OPEs rather than OPEs in urine. Since none of the matrix is suitable all the time, appropriate matrix should be selected depending on the aims of biomonitoring studies, e.g., high throughput screening or body burden estimation. Biomonitoring with non-invasive matrices such as hair and/or nail is useful to screen specific populations that might be under high exposure risks while urine is more suitable to provide valuable information on body burden. In terms of urinary monitoring, specific biomarkers have been identified for some OPE compounds, including tri(2-butoxyethyl) phosphate, tri(1,3-dichloro-2-propyl) phosphate, tri(2-chloroethyl) phosphate and tri(1-chloro-2-propyl) phosphate. Further studies are required to identify suitable urinary biomarkers for other OPE compounds, especially the emerging ones.
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Affiliation(s)
- Ying Guo
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 511443, China
| | - Chan Liang
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 511443, China
| | - Meng-Xiao Zeng
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 511443, China
| | - Gao-Ling Wei
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Managements, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Li-Xi Zeng
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 511443, China
| | - Liang-Ying Liu
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 511443, China.
| | - Eddy Y Zeng
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 511443, China
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King MD, Elliott JE, Marlatt V, Crump D, Idowu I, Wallace SJ, Tomy GT, Williams TD. Effects of Avian Eggshell Oiling With Diluted Bitumen Show Sublethal Embryonic Polycyclic Aromatic Compound Exposure. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2022; 41:159-174. [PMID: 34918379 PMCID: PMC9299908 DOI: 10.1002/etc.5250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 11/08/2021] [Accepted: 11/09/2021] [Indexed: 06/14/2023]
Abstract
Breeding birds that become oiled may contaminate the shells of their eggs, and studies of conventional crude oil suggest that even small quantities can be absorbed through the eggshell and cause embryotoxicity. Unconventional crude oils remain untested, so we evaluated whether a major Canadian oil sands product, diluted bitumen (dilbit), would be absorbed and cause toxicity when applied to eggshells of two species, domestic chicken (Gallus gallus domesticus) and double-crested cormorant (Nannopterum auritum). We artificially incubated eggs and applied lightly weathered dilbit (Cold Lake blend) to the eggshells (0.015-0.15 mg g-1 egg in chicken; 0.1-0.4 mg g-1 egg in cormorant) at various points during incubation before sampling prehatch embryos. Polycyclic aromatic compound (PAC) residue in cormorant embryos was elevated only at the highest dilbit application (0.4 mg g-1 egg) closest (day 16) to sampling on day 22. In contrast, cormorant liver cytochrome P450 1a4 (Cyp1a4) mRNA expression (quantitative polymerase chain reaction assay) was elevated only in embryos treated with the earliest and lowest dilbit application (0.1 mg g-1 egg on day 4). These results confirm that dilbit can cross through the eggshell and be absorbed by embryos, and they imply rapid biotransformation of PACs and a nonmonotonic Cyp1a4 response. Despite evidence of exposure in cormorant, we found no detectable effects on the frequency of survival, deformity, and gross lesions, nor did we find effects on physiological endpoints indicative of growth and cardiovascular function in either chicken or cormorant. In ovo dilbit exposure may be less toxic than well-studied conventional crude oils. The effects of an oil spill scenario involving dilbit to bird embryos might be subtle, and PACs may be rapidly metabolized. Environ Toxicol Chem 2022;41:159-174. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
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Affiliation(s)
- Mason D. King
- Department of Biological SciencesSimon Fraser UniversityBurnabyBritish ColumbiaCanada
| | - John E. Elliott
- Department of Biological SciencesSimon Fraser UniversityBurnabyBritish ColumbiaCanada
- Science and Technology DivisionEnvironment and Climate Change CanadaDeltaBritish ColumbiaCanada
| | - Vicki Marlatt
- Department of Biological SciencesSimon Fraser UniversityBurnabyBritish ColumbiaCanada
| | - Doug Crump
- Ecotoxicology and Wildlife Health DivisionEnvironment and Climate Change CanadaOttawaOntarioCanada
| | - Ifeoluwa Idowu
- Department of ChemistryUniversity of ManitobaWinnipegManitobaCanada
| | - Sarah J. Wallace
- Institut National de la Recherche ScientifiqueCentre Eau Terre EnvironnementQuebecQuebecCanada
| | - Gregg T. Tomy
- Department of ChemistryUniversity of ManitobaWinnipegManitobaCanada
| | - Tony D. Williams
- Department of Biological SciencesSimon Fraser UniversityBurnabyBritish ColumbiaCanada
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Ha K, Xia P, Crump D, Saini A, Harner T, O’Brien J. Cytotoxic and Transcriptomic Effects in Avian Hepatocytes Exposed to a Complex Mixture from Air Samples, and Their Relation to the Organic Flame Retardant Signature. TOXICS 2021; 9:toxics9120324. [PMID: 34941758 PMCID: PMC8704741 DOI: 10.3390/toxics9120324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 11/09/2021] [Accepted: 11/20/2021] [Indexed: 11/30/2022]
Abstract
Assessing complex environmental mixtures and their effects is challenging. In this study, we evaluate the utility of an avian in vitro screening approach to determine the effects of passive air sampler extracts collected from different global megacities on cytotoxicity and gene expression. Concentrations of a suite of organic flame retardants (OFRs) were quantified in extracts from a total of 19 megacities/major cities in an earlier study, and levels were highly variable across sites. Chicken embryonic hepatocytes were exposed to serial dilutions of extracts from the 19 cities for 24 h. Cell viability results indicate a high level of variability in cytotoxicity, with extracts from Toronto, Canada, having the lowest LC50 value. Partial least squares (PLS) regression analysis was used to estimate LC50 values from OFR concentrations. PLS modeling of OFRs was moderately predictive of LC50 (p-value = 0.0003, r2 = 0.66, slope = 0.76, when comparing predicted LC50 to actual values), although only after one outlier city was removed from the analysis. A chicken ToxChip PCR array, comprising 43 target genes, was used to determine effects on gene expression, and similar to results for cell viability, gene expression profiles were highly variable among the megacities. PLS modeling was used to determine if gene expression was related to the OFR profiles of the extracts. Weak relationships to the ToxChip expression profiles could be detected for only three of the 35 OFRs (indicated by regression slopes between 0.6 and 0.5 when comparing predicted to actual OFR concentrations). While this in vitro approach shows promise in terms of evaluating effects of complex mixtures, we also identified several limitations that, if addressed in future studies, might improve its performance.
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Affiliation(s)
- Kelsey Ha
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada;
- National Wildlife Research Centre, Environment and Climate Change Canada, Ottawa, ON K1A 0H3, Canada; (P.X.); (J.O.)
| | - Pu Xia
- National Wildlife Research Centre, Environment and Climate Change Canada, Ottawa, ON K1A 0H3, Canada; (P.X.); (J.O.)
| | - Doug Crump
- National Wildlife Research Centre, Environment and Climate Change Canada, Ottawa, ON K1A 0H3, Canada; (P.X.); (J.O.)
- Correspondence: ; Tel.: +1-(613)-998-7383
| | - Amandeep Saini
- Air Quality Processes Research Section, Environment and Climate Change Canada, Toronto, ON M3H 5T4, Canada; (A.S.); (T.H.)
| | - Tom Harner
- Air Quality Processes Research Section, Environment and Climate Change Canada, Toronto, ON M3H 5T4, Canada; (A.S.); (T.H.)
| | - Jason O’Brien
- National Wildlife Research Centre, Environment and Climate Change Canada, Ottawa, ON K1A 0H3, Canada; (P.X.); (J.O.)
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Wang X, Zhu Q, Liao C, Jiang G. Human internal exposure to organophosphate esters: A short review of urinary monitoring on the basis of biological metabolism research. JOURNAL OF HAZARDOUS MATERIALS 2021; 418:126279. [PMID: 34329041 DOI: 10.1016/j.jhazmat.2021.126279] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 05/23/2021] [Accepted: 05/29/2021] [Indexed: 06/13/2023]
Abstract
As alternatives to traditional brominated flame retardants, organophosphate flame retardants (OPFRs), especially for organophosphate esters (OPEs) -- the most widely used and investigated OPFRs, have raised people's concern on their environmental and health-related risks over the years. Considering their extensive environmental occurrence and potential adverse effects, precise estimation on the human body burden of OPEs will be conducive to the restrictions on the usage of these compounds scientifically. Biomonitoring research can provide precise information on human exposure to OPEs as it reveals the degree of external exposure from all exposure routes. Knowledge on biotransformation and metabolism of OPEs in the biosystems is of great significance for our understanding of the internal exposure to these compounds. In this study, the biological metabolic processes of nine OPEs prevalent in the environment, involving tris(2-chloroethyl) phosphate (TCEP), tris(1-chloro-2-propyl) phosphate (TCIPP), tris(1,3-dichloro-2-propyl) phosphate (TDCIPP), tripropyl phosphate (TPrP), tri-n-butyl phosphate (TnBP), tris(2-butoxyethyl) phosphate (TBOEP), triphenyl phosphate (TPhP), 2-ethylhexyl diphenyl phosphate (EHDPP), and tricresyl phosphate (TCrP), are comprehensively reviewed. Specifically, the metabolic pathway, kinetics and mechanism of OPEs are depicted in detail. Under this context, the advances and limitations on biomonitoring of OPE metabolites in human urine are summarized. The requirements of specificity, quantitative stability, high detection frequency/concentration are needed for OPE metabolites to be considered and validated as biomarkers. Thus far, deeper elucidations on the metabolic processes and identification of biomarkers of OPEs are urgently required, given that some OPEs have no suitable biomarkers in human biomonitoring. For better assessment of the body burden of OPEs in humans, reliable and effective methodologies for urine sampling and estimation on internal exposure to OPEs need to be further developed in the future.
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Affiliation(s)
- Xin Wang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qingqing Zhu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chunyang Liao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Guibin Jiang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
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Li Z, He C, Thai P, Wang X, Bräunig J, Yu Y, Luo X, Mai B, Mueller JF. Organophosphate esters and their specific metabolites in chicken eggs from across Australia: Occurrence, profile, and distribution between yolk and albumin fractions. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 262:114260. [PMID: 32114330 DOI: 10.1016/j.envpol.2020.114260] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 02/04/2020] [Accepted: 02/22/2020] [Indexed: 06/10/2023]
Abstract
A substantial increase in the usage of organophosphate esters (OPEs) as flame retardants and plasticizers in rubbers, textiles, upholstered furniture, lacquers, plastics, building materials and electronic equipment has resulted in their increasing concentrations in the environment over time. However, little is known about the concentrations and fate of OPEs and their metabolites (mOPEs) in biota, including chicken eggs. The aim of this study was to understand the spatial variation in the concentrations in chicken eggs and the partitioning between yolk and albumin. In total, 153 chicken eggs were purchased across Australia and analysed for 9 OPEs and 11 mOPE. Most of the compounds were found to be deposited in egg yolk, where diphenyl phosphate (DPHP, 3.8 ng/g wet weight, median) and tris(2-chloroisopropyl) phosphate (TCIPP, 1.8 ng/g wet weight, median) were predominant mOPE and OPE, respectively. Moreover, no spatial differences in concentrations of OPEs and mOPEs in eggs purchased from different locations were found in this study. Although comparable levels of ∑OPEs were detected in egg yolk and albumin, much higher concentrations of ∑mOPEs were found in yolk than albumin. Meanwhile, a negative correlation (R2 = 0.964, p = 0.018) was found between the molecular mass of analytes and partitioning coefficient of Cyolk/Cyolk+albumin (defined as chemical concentration in egg yolk divided by the sum of chemical concentrations in both yolk and albumin). These results indicate that n-octanol/water partition coefficients (log KOW) may not be a crucial factor in the distribution of OPEs and mOPEs between egg yolk and albumin, which is important in understanding distribution of emerging organic contaminants in biota.
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Affiliation(s)
- Zongrui Li
- State Environmental Protection Key Laboratory of Environmental Pollution Health Risk Assessment, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou, 510655, China; QAEHS, Queensland Alliance for Environmental Health Science, The University of Queensland, 4102, Brisbane, Australia; State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China
| | - Chang He
- QAEHS, Queensland Alliance for Environmental Health Science, The University of Queensland, 4102, Brisbane, Australia.
| | - Phong Thai
- QAEHS, Queensland Alliance for Environmental Health Science, The University of Queensland, 4102, Brisbane, Australia
| | - Xianyu Wang
- QAEHS, Queensland Alliance for Environmental Health Science, The University of Queensland, 4102, Brisbane, Australia
| | - Jennifer Bräunig
- QAEHS, Queensland Alliance for Environmental Health Science, The University of Queensland, 4102, Brisbane, Australia
| | - Yunjiang Yu
- State Environmental Protection Key Laboratory of Environmental Pollution Health Risk Assessment, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou, 510655, China
| | - Xiaojun Luo
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China
| | - Bixian Mai
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China
| | - Jochen F Mueller
- QAEHS, Queensland Alliance for Environmental Health Science, The University of Queensland, 4102, Brisbane, Australia
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Chen S, Gong Z, Letcher RJ, Liu C. Promotion effect of liver tumor progression in male kras transgenic zebrafish induced by tris (1, 3-dichloro-2-propyl) phosphate. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 191:110220. [PMID: 31991394 DOI: 10.1016/j.ecoenv.2020.110220] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 01/10/2020] [Accepted: 01/14/2020] [Indexed: 06/10/2023]
Abstract
A previous study reported that exposure to tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) could promote the progression of hepatocellular carcinoma (HCC) in female HCC model zebrafish. Due to the existence of gender disparity in the development of HCC between females and males, whether the promotion effect of TDCIPP still exists in male HCC model zebrafish remains unclear. In this study, Tg(fabp10:rtTA2s-M2; TRE2:EGFP-krasG12V), referred as kras transgenic zebrafish which was shown to be an inducible liver tumor model, was applied as experimental model to assess the promotion potential of TDCIPP for HCC in males. In brief, kras males were exposed to 20 mg/L doxycycline (DOX), 0.3 mg/L TDCIPP and a binary mixture of 20 mg/L DOX with 0.3 mg/L TDCIPP, and after exposure liver size, histopathology and transcriptional profiles of liver from these treatments were examined. With the involvement of TDCIPP, the liver size was significantly increased and the lesion of hepatocyte became more aggressive. Furthermore, expressions of genes involved in DNA replication and inflammatory response were simultaneously up-regulated in the treatment of TDCIPP compared with the solvent control and in the treatment of the binary mixture of the two chemicals compared to the single DOX treatment. Overall, our results suggested that TDCIPP had promotion effect on the progression of liver tumor in kras males.
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Affiliation(s)
- Sheng Chen
- Hubei Provincial Engineering Laboratory for Pond Aquaculture, College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China
| | - Zhiyuan Gong
- Department of Biological Sciences, National University of Singapore, 117543, Singapore
| | - Robert J Letcher
- Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University, Ottawa, Ontario, K1A 0H3, Canada
| | - Chunsheng Liu
- Hubei Provincial Engineering Laboratory for Pond Aquaculture, College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China.
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Yin SY, Chen L, Wu DY, Wang T, Huo LJ, Zhao S, Zhou J, Zhang X, Miao YL. Tris(1,3-dichloro-2-propyl) phosphate disturbs mouse embryonic development by inducing apoptosis and abnormal DNA methylation. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2019; 60:807-815. [PMID: 31411769 DOI: 10.1002/em.22322] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Revised: 06/15/2019] [Accepted: 08/11/2019] [Indexed: 05/21/2023]
Abstract
Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) is a kind of additive flame retardants (FRs) and was found to affect early embryonic development in zebrafish; however, there are few studies to investigate whether TDCPP will disturb the development of early mouse embryos. In our studies, we used mouse embryos as models to study the toxicology of TDCPP on the early embryos. The results showed that TDCPP disturbed the development of early mouse embryos in a dose-dependent manner. 10 μM TDCPP decreased the blastocyst formation and 100 μM TDCPP was a lethal concentration for the mouse embryos. We proved that TDCPP was detrimental to embryonic development potential by increasing the reactive oxygen species level and inducing early apoptosis. Furthermore, TDCPP changed the DNA methylation patterns of imprinted genes in treated blastocysts. The methylation of H19 and Snrpn promoter regions was increased from 37.67% to 46.00% and 31.56% to 44.38% in treated groups, respectively. In contrast, Peg3 promoter region methylation was declined from 86.55% to 73.27% in treated embryos. Taken together, our results demonstrated that TDCPP could adversely impair the early embryonic development in mouse. Environ. Mol. Mutagen. 2019. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- Shu-Yuan Yin
- Institute of Stem Cell and Regenerative Biology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Li Chen
- Institute of Stem Cell and Regenerative Biology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Dan-Ya Wu
- Institute of Stem Cell and Regenerative Biology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Tao Wang
- Institute of Stem Cell and Regenerative Biology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Li-Jun Huo
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Shuhong Zhao
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Jilong Zhou
- Institute of Stem Cell and Regenerative Biology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Xia Zhang
- Institute of Stem Cell and Regenerative Biology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- National Demonstration Center for Experimental Veterinary Medicine Education, Huazhong Agricultural University, Wuhan, China
| | - Yi-Liang Miao
- Institute of Stem Cell and Regenerative Biology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- Department of Reproductive Medical Center, Huangshi Central Hospital, Huangshi, Hubei, China
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Chen S, Dang Y, Gong Z, Letcher RJ, Liu C. Progression of liver tumor was promoted by tris(1,3-dichloro-2-propyl) phosphate through the induction of inflammatory responses in kras V12 transgenic zebrafish. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 255:113315. [PMID: 31606661 DOI: 10.1016/j.envpol.2019.113315] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 09/19/2019] [Accepted: 09/27/2019] [Indexed: 06/10/2023]
Abstract
Tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) has been detected in various environmental media and has been implicated as a weak mutagen or carcinogen, but whether TDCIPP can promote the progression of liver tumor remains unclear. In this study, krasV12 genetically modified zebrafish, Tg(fabp10:rtTA2s-M2; TRE2:EGFP-krasG12V), a model system in which liver tumors can be induced by doxycycline (DOX), was used to evaluate the liver tumor promotion potential of TDCIPP. Briefly, krasV12 transgenic females were exposed to 0.3 mg/L TDCIPP, 20 mg/L DOX or a binary mixture of 0.3 mg/L TDCIPP with 20 mg/L DOX, and liver size, histopathology, and transcriptional profiles of liver were determined. Treatment with TDCIPP resulted in increased liver size and caused more aggressive hepatocellular carcinoma (HCC). Compared with the exposure to DOX, TDCIPP in the presence of DOX up-regulated the expression of genes relevant with salmonella infection and the toll-like receptor signaling pathway. These results implied an occurrence of inflammatory reaction, which was sustained by the increase in the amount of infiltrated neutrophils in the liver of Tg(lyz:DsRed2) transgenic zebrafish larvae whose neutrophils were labelled by red fluorescent protein under the lysozyme C promoter. Furthermore, compared with the binary exposure of DOX and TDCIPP, treatment with a ternary mixture of TDCIPP, DOX and inflammatory response inhibitor (ketoprofen) significantly decrease the liver size and the amounts of neutrophils in the livers of kras and lyz double transgenic zebrafish larvae. Collectively, our results suggested that TDCIPP could promote the liver tumor progression by induction of hepatic inflammatory responses.
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Affiliation(s)
- Sheng Chen
- Hubei Provincial Engineering Laboratory for Pond Aquaculture, College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yao Dang
- Hubei Provincial Engineering Laboratory for Pond Aquaculture, College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China
| | - Zhiyuan Gong
- Department of Biological Sciences, National University of Singapore, 117543, Singapore
| | - Robert J Letcher
- Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University, Ottawa, Ontario, K1A 0H3, Canada
| | - Chunsheng Liu
- Hubei Provincial Engineering Laboratory for Pond Aquaculture, College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China.
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Wang C, An J, Bai Y, Li H, Chen H, Ou D, Liu Y. Tris(1,3-dichloro-2-propyl) phosphate accelerated the aging process induced by the 4-hydroxynon-2-enal response to reactive oxidative species in Caenorhabditis elegans. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 246:904-913. [PMID: 31159140 DOI: 10.1016/j.envpol.2018.12.082] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 12/14/2018] [Accepted: 12/26/2018] [Indexed: 05/20/2023]
Abstract
Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) has been frequently detected in environmental media and biological samples. However, knowledge of its adverse health consequences is limited. In the current study, Caenorhabditis elegans (C. elegans, L1 larvae) were exposed to TDCPP at environmentally relevant concentrations (control, 0.1, 1, 100 and 1000 μg L-1) for 72 h to explore any association between TDCPP and the aging process. Some of the degenerative age-related indicators were observed, including locomotion behaviors and lifespan. As crucial biomarkers of aging, the accumulation of lipofuscin, and lipid peroxidation (LPO) products exemplified by 4-hydroxynon-2-enal (4-HNE) were detected. This product forms as a result of oxidative stress, as confirmed by an N-acetyl-L-cysteine (NAC) pharmacological assay. Moreover, a significant increase in reactive oxide species (ROS) production in a dose-dependent manner using a fluorescent probe was observed. For the underlying molecular mechanism of the above aging phenotypes, significantly upregulated transcription of genes related to antioxidant systems, especially a subset of glutathione S-transferase (gst-5, gst-6, gst-9, gst-10, gst-19, gst-24, gst-26, gst-29, gst-33, and gst-38), was found by RNA-Seq and further confirmed by RT-qPCR. The elevated glutathione S-transferase (GST) was attributed to the significant increase in 4-HNE because mutations in gst-5 and gst-24 inhibited the conjugation of GSTs with 4-HNE. Therefore, GST play an indispensable role in the detoxification process of TDCPP exposure and further confirmed LPO accumulation at the molecular mechanism level. In conclusion, TDCPP accelerated the aging process induced by the LPO products, 4-HNE, response to reactive oxidative species in C. elegans.
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Affiliation(s)
- Chen Wang
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, PR China
| | - Jing An
- Institute for Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, PR China
| | - Yingchen Bai
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Science, Beijing, 10012, PR China
| | - Hui Li
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, PR China; Institute for Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, PR China.
| | - Haibo Chen
- Center for Environmental Health Research, South China Institute of Environmental Sciences, MEP, Guangzhou, 510535, PR China
| | - Dong Ou
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, PR China
| | - Yongdi Liu
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, PR China
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10
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Pagé-Larivière F, Chiu S, Jones SP, Farhat A, Crump D, O'Brien JM. Prioritization of 10 organic flame retardants using an avian hepatocyte toxicogenomic assay. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2018; 37:3134-3144. [PMID: 30133003 DOI: 10.1002/etc.4260] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 08/08/2018] [Accepted: 08/20/2018] [Indexed: 06/08/2023]
Abstract
As the number of chemicals developed and used by industry increases, the inherent limitations of traditional toxicology approaches become an unavoidable issue. To help meet the demand for toxicity evaluation, new methods, such as high-throughput toxicity screening, are currently being developed to permit rapid determination of toxic, molecular, and/or biochemical effects of a wide range of chemicals. In the present study, we demonstrate the utility of an avian in vitro toxicogenomics screening approach to determine the cytotoxic and transcriptomic effects of 10 organic flame retardants (OFRs) currently of international priority for ecological risk evaluation to prioritize and inform future toxicological studies. Hepatocytes from 2 avian species, chicken and double-crested cormorant, were prepared and exposed for 24 h to various concentrations (0-300 μM) of the following 10 OFRs: Chemical Abstracts Service registration numbers 29761-21-5, 56803-37-3 (p-tert-butylphenyl diphenyl phosphate [BPDP]), 65652-41-7, 68937-41-7 (phenol, isopropylated, phosphate [3:1] [IPPP]), 95906-11-9, 19186-97-1, 26040-51-7, 35948-25-5, 21850-44-2, and 25713-60-4. Cell viability, the 7-ethoxyresorufin-O-deethylase assay, and transcriptomic analysis using species-specific ToxChip polymerase chain reaction arrays were performed to evaluate the in vitro effect of these OFRs. Of the 10 OFRs assessed, BPDP and IPPP elicited the strongest cytotoxic and transcriptomic responses in both chicken and double-crested cormorant hepatocytes and are therefore recommended as priority candidates for further wildlife toxicological investigations. Environ Toxicol Chem 2018;37:3134-3144. © 2018 Crown in the right of Canada. Published by Wiley Periodicals Inc. on behalf of SETAC.
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Affiliation(s)
- Florence Pagé-Larivière
- National Wildlife Research Centre, Environment and Climate Change Canada, Ottawa, Ontario, Canada
| | - Suzanne Chiu
- National Wildlife Research Centre, Environment and Climate Change Canada, Ottawa, Ontario, Canada
| | - Stephanie P Jones
- National Wildlife Research Centre, Environment and Climate Change Canada, Ottawa, Ontario, Canada
| | - Amani Farhat
- National Wildlife Research Centre, Environment and Climate Change Canada, Ottawa, Ontario, Canada
| | - Doug Crump
- National Wildlife Research Centre, Environment and Climate Change Canada, Ottawa, Ontario, Canada
| | - Jason M O'Brien
- National Wildlife Research Centre, Environment and Climate Change Canada, Ottawa, Ontario, Canada
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11
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Zhu Y, Lin D, Yang D, Jia Y, Liu C. Environmentally relevant concentrations of the flame retardant tris(1,3-dichloro-2-propyl) phosphate change morphology of female zebrafish. CHEMOSPHERE 2018; 212:358-364. [PMID: 30145427 DOI: 10.1016/j.chemosphere.2018.08.083] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 08/15/2018] [Accepted: 08/16/2018] [Indexed: 06/08/2023]
Abstract
Tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) was considered as a re-emerging environmental pollutant, and accumulated evidences suggested that it was global distributed in various environmental media. However, effect of TDCIPP on fish morphology remained largely unknown. In this study, one-month old zebrafish (Danio rerio) were exposed to 0, 0.05, 0.5 or 5 μg/L TDCIPP for 120 days, and effects on fish morphology and expressions of genes included in the development of muscle and bone were examined. Using landmark-based geometric morphometrics, we found that environmentally relevant concentrations of TDCIPP altered morphology of female zebrafish. Furthermore, TDCIPP decreased the ratio of caudal fin area to whole body area and muscle density. These effects were possibly resulted from the alteration in the expression of genes included in the development of muscle (myf5 and myog) and bone (bmp2b and bmp4).
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Affiliation(s)
- Ya Zhu
- College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China; Department of Environmental Science, Zhejiang University, Hangzhou, 310058, China
| | - Daohui Lin
- Department of Environmental Science, Zhejiang University, Hangzhou, 310058, China
| | - Dandong Yang
- College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yali Jia
- College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China
| | - Chunsheng Liu
- College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China; Collaborative Innovation Center for Efficient and Health Production of Fisheries in Hunan Province, Hunan, Changde, 415000, China.
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12
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Zhang Y, Li M, Li S, Wang Q, Zhu G, Su G, Letcher RJ, Liu C. Exposure to tris(1,3-dichloro-2-propyl) phosphate for Two generations decreases fecundity of zebrafish at environmentally relevant concentrations. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2018; 200:178-187. [PMID: 29775925 DOI: 10.1016/j.aquatox.2018.05.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Revised: 05/09/2018] [Accepted: 05/10/2018] [Indexed: 06/08/2023]
Abstract
Previous studies reported that exposure to environmentally relevant concentrations of TDCIPP significantly decreased the number of cumulative eggs in zebrafish, but effects on the quantity of eggs and sperms remained unknown. Therefore, in this study, effects of TDCIPP on yolk diameter, surface morphology of eggs, sperm density and total motility were evaluated. First generation (F0) zebrafish larvae (Danio rerio) were exposed to 0, 50, 500 or 5000 ng/L tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) from 14 days post fertilization (dpf) to 120 dpf. The F0 generation of zebrafish were paired and F1 generation of embryos were collected and continuously exposed to the same concentrations of TDCIPP until 150 dpf. TDCIPP bioconcentration in the whole body as well as effects on survival and fecundity were evaluated in F1 generation. Exposure to TDCIPP resulted in an accumulation of the chemical and decreased survival of F1 generation of zebrafish. TDCIPP decreased cumulative production and changed surface morphology of eggs in females. In males, TDCIPP decreased total motility of sperm but did not affect sperm density. These effects on quality of egg and sperm might be responsible for the decreased hatching rates observed in cross mating experiments. Furthermore, TDCIPP exposure resulted in down-regulated gene expression related to gonadal development and maturation of germ cells in females or/and males, and the down-regulation was correlated to decreased fecundity. Taken together, the results suggested that exposure to TDCIPP could decrease the quantity of eggs and sperms by down-regulating the expression of genes related to gonadal development and maturation of germ cells in zebrafish.
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Affiliation(s)
- Yongkang Zhang
- College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China
| | - Meng Li
- Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, 310058, China
| | - Shuying Li
- Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, 310058, China
| | - Qiangwei Wang
- Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, 310058, China
| | - Guonian Zhu
- Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, 310058, China
| | - Guanyong Su
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Robert J Letcher
- Departments of Chemistry and Biology, Carleton University, Ottawa, Ontario, K1S 5B6, Canada
| | - Chunsheng Liu
- College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China; Collaborative Innovation Centre for Efficient and Health Production of Fisheries in Hunan Province, Changde, 415000, China.
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13
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Briels N, Løseth ME, Ciesielski TM, Malarvannan G, Poma G, Kjærvik SA, Léon A, Cariou R, Covaci A, Jaspers VLB. In ovo transformation of two emerging flame retardants in Japanese quail (Coturnix japonica). ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 149:51-57. [PMID: 29149662 DOI: 10.1016/j.ecoenv.2017.10.069] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 10/24/2017] [Accepted: 10/31/2017] [Indexed: 06/07/2023]
Abstract
Tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) and Dechlorane Plus (DP) are two chlorinated, alternative flame retardants that have been found in wild birds and bird eggs. Little is known about the fate and effect of these compounds in birds, especially during the vulnerable stages of embryonic development. To investigate the ability of birds to biotransform these compounds, an in ovo exposure experiment with Japanese quail eggs was performed. Quail eggs were injected in the yolk sac with 1000ng/g egg of TDCIPP (2.3 nmol/g ww), DP (1.5 nmol/g ww) or a mixture of both and were then incubated at 37.5°C for 17 days. To get a time-integrated understanding of the in ovo transformation of the compounds, one egg per treatment was removed from the incubator every day and analyzed for TDCIPP and its metabolite bis(1,3-dichloro-2-propyl) phosphate (BDCIPP) and/or for DP. By the end of the incubation period, TDCIPP was completely metabolized, while simultaneously BDCIPP was formed. The conversion of the parent compound into the metabolite did not occur proportionally and the concentration of BDCIPP showed a tendency to decrease when TDCIPP became depleted, both indicating that BDCIPP was further transformed into compounds not targeted for analysis. Further untargeted investigations did not show the presence of other metabolites, possibly due to the volatility of the metabolites. On the other hand, the DP concentration did not decrease during egg incubation. This study indicates that within the incubation period, avian embryos are able to biotransform TDCIPP, but not DP.
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Affiliation(s)
- Nathalie Briels
- Envitox Group, Department of Biology, Norwegian University of Science and Technology, Høgskoleringen 5, 7491 Trondheim, Norway.
| | - Mari E Løseth
- Envitox Group, Department of Biology, Norwegian University of Science and Technology, Høgskoleringen 5, 7491 Trondheim, Norway
| | - Tomasz M Ciesielski
- Envitox Group, Department of Biology, Norwegian University of Science and Technology, Høgskoleringen 5, 7491 Trondheim, Norway
| | - Govindan Malarvannan
- Toxicological Centre, Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Giulia Poma
- Toxicological Centre, Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Sara A Kjærvik
- Envitox Group, Department of Biology, Norwegian University of Science and Technology, Høgskoleringen 5, 7491 Trondheim, Norway
| | - Alexis Léon
- LUNAM Université, Oniris, Laboratoire d'Etude des Résidus et Contaminants dans les Aliments (LABERCA), UMR INRA 1329, 44307 Nantes, France
| | - Ronan Cariou
- LUNAM Université, Oniris, Laboratoire d'Etude des Résidus et Contaminants dans les Aliments (LABERCA), UMR INRA 1329, 44307 Nantes, France
| | - Adrian Covaci
- Toxicological Centre, Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Veerle L B Jaspers
- Envitox Group, Department of Biology, Norwegian University of Science and Technology, Høgskoleringen 5, 7491 Trondheim, Norway
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14
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Hill KL, Hamers T, Kamstra JH, Willmore WG, Letcher RJ. Organophosphate triesters and selected metabolites enhance binding of thyroxine to human transthyretin in vitro. Toxicol Lett 2018; 285:87-93. [PMID: 29306024 DOI: 10.1016/j.toxlet.2017.12.030] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 11/10/2017] [Accepted: 12/31/2017] [Indexed: 01/01/2023]
Abstract
The toxicological properties of organophosphate (OP) triesters that are used as flame retardants and plasticizers are currently not well understood, though increasing evidence suggests they can affect the thyroid system. Perturbation of thyroid hormone (TH) transport is one mechanism of action that may affect thyroid function. The present study applied an in vitro competitive protein binding assay with thyroxine (T4) and human transthyretin (hTTR) transport protein to determine the potential for the OP triesters, TDCIPP (tris(1,3-dichloro-2-propyl) phosphate), TBOEP (tris(butoxyethyl) phosphate), TEP (triethyl phosphate), TPHP (triphenyl phosphate), p-OH-TPHP (para-hydroxy triphenyl phosphate), and the OP diester DPHP (diphenyl phosphate), to competitively displace T4 from hTTR. Enhancement of T4 binding to hTTR, rather than the hypothesized competition, was observed for the six OP esters and in a concentration-dependent manner. For example, T4-hTTR binding was significantly increased at concentrations of TBOEP as low as 64 nM, and up to 184% of controls at 5000 nM. A plausible explanation of these results, which to our knowledge has not been previously reported, may be allosteric interactions of the OP esters with hTTR allowing T4 to access the second site of the TH binding pocket. These in vitro results suggest a novel mechanism of OP ester toxicity via T4 binding enhancement, and possible dysregulation of T4-hTTR interactions.
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Affiliation(s)
- Katie L Hill
- Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University, Ottawa, Canada; Department of Biology, Carleton University, Ottawa, Canada; Intrinsik Corp., Ottawa, Canada
| | - Timo Hamers
- Department of Environment and Health, Vrije Universiteit Amsterdam, The Netherlands
| | - Jorke H Kamstra
- Faculty of Veterinary Medicine and Biosciences, Department of Basic Science and Aquatic Medicine, CoE CERAD, Norwegian University of Life Sciences, Oslo, 0033, Norway
| | | | - Robert J Letcher
- Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University, Ottawa, Canada; Department of Biology, Carleton University, Ottawa, Canada.
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15
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Chen H, Wang P, Du Z, Wang G, Gao S. Oxidative stress, cell cycle arrest, DNA damage and apoptosis in adult zebrafish (Danio rerio) induced by tris(1,3-dichloro-2-propyl) phosphate. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2018; 194:37-45. [PMID: 29149642 DOI: 10.1016/j.aquatox.2017.11.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 10/31/2017] [Accepted: 11/01/2017] [Indexed: 06/07/2023]
Abstract
Tris(1,3-dichloro-2-propyl)phosphate (TDCPP) is an additive flame retardant of high production volume, and frequently detected in biota and environment. However, knowledge on its potential risk and toxicological mechanism still remains limited. In this study, DNA damage, transcriptomic responses and biochemical changes in the liver of zebrafish (Danio rerio) induced by TDCPP were investigated. Zebrafish was exposed to 45.81μg/L (1/100 (96h-LC50)) and 229.05μg/L (1/20 (96h-LC50)) TDCPP for 7 d. The reactive oxygen species (ROS) and GSH contents, in addition to antioxidant enzyme activities in the liver changed significantly, and the mRNA levels of genes related to oxidative stress were alerted in a dose-dependent and/or sex-dependent manner after exposure to TDCPP. Significant DNA damage in zebrafish liver was found, and olive tail moment increased in a concentration-dependent manner. Moreover, exposure of TDCPP at 45.81μg/L level activated the cell cycle arrest, DNA repair system and apoptosis pathway in male zebrafish, and 229.05μg/L TDCPP exposure inhibited those pathways in both male and female zebrafish. The cell apoptosis was confirmed in TUNEL assay as higher incidence of TUNEL-positive cells were observed in zebrafish exposed to 229.05μg/L TDCPP. Our results also indicated that males were more sensitive to TDCPP exposure compared with females. Taken together, our results showed that TDCPP could induce oxidative stress, cell cycle arrest, DNA damage and apoptosis in adult zebrafish liver in sex- and concentration-dependent manners.
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Affiliation(s)
- Hanyan Chen
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, China
| | - Pingping Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, China
| | - Zhongkun Du
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, China
| | - Guowei Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, China
| | - Shixiang Gao
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, China.
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16
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Fernie KJ, Chabot D, Champoux L, Brimble S, Alaee M, Marteinson S, Chen D, Palace V, Bird DM, Letcher RJ. Spatiotemporal patterns and relationships among the diet, biochemistry, and exposure to flame retardants in an apex avian predator, the peregrine falcon. ENVIRONMENTAL RESEARCH 2017; 158:43-53. [PMID: 28599194 DOI: 10.1016/j.envres.2017.05.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 05/26/2017] [Accepted: 05/28/2017] [Indexed: 06/07/2023]
Abstract
Flame retardants (FR) are industrial chemicals and some are proven environmental contaminants that accumulate in predatory birds. Few studies have examined the influence of diet on FR profiles in nestling raptors and the possible physiological implications of such FR exposure. The objectives of this research were (1) to determine spatial patterns of ≤ 48 polybrominated diphenyl ether (PBDE) congeners and ≤ 26 non-PBDE FRs, including organophosphate esters (OPEs), in nestling peregrine falcons (Falco peregrinus) across the Canadian Great Lakes-St. Lawrence River Basin (GL-SLR; 2010) and in the eastern Canadian Arctic (2007); (2) to identify temporal changes in FR concentrations from the mid-2000s to 2010 in GL-SLR peregrine nestlings; (3) to investigate the role of diet using stable isotopes on exposure patterns of quantifiable FRs; and (4) to assess possible associations between circulating FRs and total (T) thyroxine (TT4) and triiodothyronine (TT3), tocopherol, retinol and oxidative status (isoprostanes). The summed concentrations of the top 5 PBDEs (Σ5) (BDE-47, -99, -100, -154, -153) were significantly higher in rural nestlings than urban nestlings in the GL-SLR, followed by the eastern Arctic nestlings. The PBDE congener profile of rural nestlings was dominated by BDE-99 (34‰), whereas BDE-209 (31‰) became dominant in the 2010 urban PBDE profile marking a shift since the mid-2000s. Low (ppb) concentrations of 25 novel non-PBDE FRs (e.g., 1,2-bis-(2,4,6-tribromophenoxy)ethane (BTBPE), decabromodiphenylethane (DBDPE)) were measured in the nestlings in at least one region, with the first report in peregrines of 15 novel non-PBDE FRs (e.g., 2-ethyl-1-hyxyl 2,3,4,5-tetrabromobenzoate (EHTBB), pentabromo allyl ether (PBPAE), tetrabromoethylcyclohexane (α-, β-DBE-DBCH)) as well as of tris (2-butoxyethyl) phosphate (TBOEP) (0-7.5ng/g ww) > tris(2-chloroisopropyl) phosphate (TCIPP) (0.1-5.5ng/g ww) > tris(2-chloroethyl) phosphate (TCEP) (0.02-2.0ng/g ww) > tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) (0-1.0ng/g ww). Within the GL-SLR, the urban nestlings' diet had significantly more terrestrial sources (greater δ13C values) than the broader, more aquatic-based diet of rural peregrines. Dietary source (δ13C) was significantly associated with concentrations of Σ5PBDE, BDE-209, EHTBB, and 2,2-4,4',5,5'-hexabromobiphenyl (BB-153), with trophic level (δ15N) also positively associated with BDE-209 levels. Compared to urban nestlings, the rural nestlings had significantly lower circulating concentrations of thyroxine (TT4), triiodothyronine (TT3), a greater proportion of TT3 relative to TT4 (TT3:TT4), tocopherol and oxidative status (isoprostanes), but higher retinol levels; the most recalcitrant PBDE congener, BDE-153, in combination with low concentrations of some novel FRs, particularly octabromotrimethylphenyllindane (OBIND), may influence circulating thyroid hormones, especially TT4, and retinol levels of peregrine falcon nestlings. These associations of FR-endocrine-biochemical measures suggest possible exposure-related changes in these birds and further study is warranted.
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Affiliation(s)
- Kim J Fernie
- Ecotoxicology & Wildlife Health Division, Science & Technology Branch, Environment and Climate Change Canada, Burlington, Ontario, Canada.
| | - Dominique Chabot
- Avian Science and Conservation Centre, Department of Natural Resource Sciences, McGill University, Ste-Anne-de-Bellevue, Quebec, Canada
| | - Louise Champoux
- Ecotoxicology & Wildlife Health Division, Science & Technology Branch, Environment and Climate Change Canada, Quebec City, Quebec, Canada
| | - Samantha Brimble
- Ecotoxicology & Wildlife Health Division, Science & Technology Branch, Environment and Climate Change Canada, Burlington, Ontario, Canada; Aquatic Contaminants Research Division, Science & Technology Branch, Environment and Climate Change Canada, Burlington, Ontario, Canada
| | - Mehran Alaee
- Aquatic Contaminants Research Division, Science & Technology Branch, Environment and Climate Change Canada, Burlington, Ontario, Canada
| | - Sarah Marteinson
- Ecotoxicology & Wildlife Health Division, Science & Technology Branch, Environment and Climate Change Canada, Burlington, Ontario, Canada
| | - Da Chen
- Cooperative Wildlife Research Laboratory and Department of Zoology, Southern Illinois University, Carbondale, IL, USA
| | - Vince Palace
- International Institute for Sustainable Development - Experimental Lakes Area (IISD-ELA), Winnipeg, Manitoba, Canada
| | - David M Bird
- Avian Science and Conservation Centre, Department of Natural Resource Sciences, McGill University, Ste-Anne-de-Bellevue, Quebec, Canada
| | - Robert J Letcher
- Ecotoxicology & Wildlife Health Division, Science & Technology Branch, Environment and Climate Change Canada, National Wildlife Research Centre, Ottawa, Ontario, Canada
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17
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Guigueno MF, Fernie KJ. Birds and flame retardants: A review of the toxic effects on birds of historical and novel flame retardants. ENVIRONMENTAL RESEARCH 2017; 154:398-424. [PMID: 28193557 DOI: 10.1016/j.envres.2016.12.033] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 11/17/2016] [Accepted: 12/20/2016] [Indexed: 05/28/2023]
Abstract
Flame retardants (FRs) are a diverse group of chemicals, many of which persist in the environment and bioaccumulate in biota. Although some FRs have been withdrawn from manufacturing and commerce (e.g., legacy FRs), many continue to be detected in the environment; moreover, their replacements and/or other novel FRs are also detected in biota. Here, we review and summarize the literature on the toxic effects of various FRs on birds. Birds integrate chemical information (exposure, effects) across space and time, making them ideal sentinels of environmental contamination. Following an adverse outcome pathway (AOP) approach, we synthesized information on 8 of the most commonly reported endpoints in avian FR toxicity research: molecular measures, thyroid-related measures, steroids, retinol, brain anatomy, behaviour, growth and development, and reproduction. We then identified which of these endpoints appear more/most sensitive to FR exposure, as determined by the frequency of significant effects across avian studies. The avian thyroid system, largely characterized by inconsistent changes in circulating thyroid hormones that were the only measure in many such studies, appears to be moderately sensitive to FR exposure relative to the other endpoints; circulating thyroid hormones, after reproductive measures, being the most frequently examined endpoint. A more comprehensive examination with concurrent measurements of multiple thyroid endpoints (e.g., thyroid gland, deiodinase enzymes) is recommended for future studies to more fully understand potential avian thyroid toxicity of FRs. More research is required to determine the effects of various FRs on avian retinol concentrations, inconsistently sensitive across species, and to concurrently assess multiple steroid hormones. Behaviour related to courtship and reproduction was the most sensitive of all selected endpoints, with significant effects recorded in every study. Among domesticated species (Galliformes), raptors (Accipitriformes and Falconiformes), songbirds (Passeriformes), and other species of birds (e.g. gulls), raptors seem to be the most sensitive to FR exposure across these measurements. We recommend that future avian research connect biochemical disruptions and changes in the brain to ecologically relevant endpoints, such as behaviour and reproduction. Moreover, connecting in vivo endpoints with molecular endpoints for non-domesticated avian species is also highly important, and essential to linking FR exposure with reduced fitness and population-level effects.
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Affiliation(s)
- Mélanie F Guigueno
- Environment and Climate Change Canada, Canada Centre for Inland Waters, 867 Lakeshore Road, Burlington, Ontario, Canada L7S 1A1; Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, 21 111 Lakeshore Road, Sainte-Anne-de-Bellevue, Québec, Canada H9X 3V9
| | - Kim J Fernie
- Environment and Climate Change Canada, Canada Centre for Inland Waters, 867 Lakeshore Road, Burlington, Ontario, Canada L7S 1A1.
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18
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Su G, Letcher RJ, Moore JN, Williams LL, Grasman KA. Contaminants of emerging concern in Caspian tern compared to herring gull eggs from Michigan colonies in the Great Lakes of North America. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2017; 222:154-164. [PMID: 28089466 DOI: 10.1016/j.envpol.2016.12.061] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 11/23/2016] [Accepted: 12/23/2016] [Indexed: 06/06/2023]
Abstract
A broad suite of 87 contaminants of emerging concern (CECs), including 26 polybrominated diphenyl ethers (PBDEs), 23 non-PBDEs halogenated FRs (NPHFRs), 16 organophosphate esters (OPEs), 4 perfluorinated sulfonates (PFSAs), 13 perfluorinated carboxylic acids (PFCAs) and 5 emerging perfluoroalkyl acids (PFAAs) or precursors, were determined in 30 individual Caspian tern (listed as a threatened species in the U.S. State of Michigan) eggs collected in 2013 and 2014 from Michigan nesting sites on Two Tree Island (St, Mary's River), Charity Reef (Saginaw Bay) and Channel-Shelter Island (a Confined Disposal Facility (CDF) in Saginaw Bay). The same CEC suite was determined in 10 herring gull eggs on the Pipe Island Twins in the lower St. Mary's River. In tern eggs, the order of concentrations were ΣPFSA (mean: 793 ng/g wet weight (ww); range: 116-4690 ng/g ww) > ΣPFCAs (131; 30.4-506 ng/g ww) ≈ ΣPBDEs (86.7; 32.4-189 ng/g ww) » ΣNPHFRs (0.67; ND-4.3 ng/g ww) ≈ ΣOPEs (0.46; ND-2.89 ng/g ww). Compared to gull eggs collected from the same area, tern egg exposure contained significantly lower concentrations of ΣPBDE, but with up to 10 times greater mean concentrations of ΣPFSAs and ΣPFCAs. This study highlights the importance of consistent monitoring in eggs of different Great Lakes birds of PBDEs, perfluorooctane sulfonate (PFOS) and perfluoro-4-ethylcyclohexane sulfonate (PFEtCHxS) given that: 1) PBDE concentrations in all analyzed avian eggs exceeded or approached a concentration of 29 ng/g ww, which for birds is the current Canadian FEQG (Federal Environmental Quality Guideline); 2) ΣPBDE concentrations were comparable to lowest observed effect concentration (LOEC) values reported in the literature; 3) PFOS concentrations in Caspian tern eggs were extremely high with many eggs across sites exceeding 1 ppm, and with the greatest being up to 4.7 ppm; and 4) PFEtCHxS, a potentially persistent and bioaccumulative substance, showed a detection frequency of 100% in 40 of the analyzed eggs.
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Affiliation(s)
- Guanyong Su
- Ecotoxicology and Wildlife Health Division, Wildlife and Landscape Directorate, Science and Technology Branch, Environment and Climate Change Canada, National Wildlife Research Center, Carleton University, Ottawa, ON, Canada; Department of Chemistry, Carleton University, Ottawa, ON, K1S 5B6, Canada
| | - Robert J Letcher
- Ecotoxicology and Wildlife Health Division, Wildlife and Landscape Directorate, Science and Technology Branch, Environment and Climate Change Canada, National Wildlife Research Center, Carleton University, Ottawa, ON, Canada; Department of Chemistry, Carleton University, Ottawa, ON, K1S 5B6, Canada.
| | - Jeremy N Moore
- U.S. Fish and Wildlife Service, East Lansing Ecological Services Field Office, East Lansing, MI, USA
| | - Lisa L Williams
- U.S. Fish and Wildlife Service, East Lansing Ecological Services Field Office, East Lansing, MI, USA
| | - Keith A Grasman
- Department of Biology, Calvin College, Grand Rapids, MI, 49546, USA
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19
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Li J, Ma X, Su G, Giesy JP, Xiao Y, Zhou B, Letcher RJ, Liu C. Multigenerational effects of tris(1,3-dichloro-2-propyl) phosphate on the free-living ciliate protozoa Tetrahymena thermophila exposed to environmentally relevant concentrations and after subsequent recovery. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2016; 218:50-58. [PMID: 27552037 DOI: 10.1016/j.envpol.2016.08.034] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 07/29/2016] [Accepted: 08/10/2016] [Indexed: 06/06/2023]
Abstract
Tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) is considered a re-emerging environmental pollutant, and exposure to environmentally relevant concentrations has been shown to cause individual developmental toxicity in zebrafish and the water flea (Daphnia magna). However, multigenerational effects during exposure to TDCIPP and after subsequent recovery were unknown. In the present study, individuals of a model aquatic organism, the ciliated protozoan, T. thermophila were exposed to environmentally-relevant concentrations of TDCIPP (0, 300 or 3000 ng/L) for 60 days (e.g., theoretically 372 generations) followed by a 60-day period of recovery, during which T. thermophila were not exposed to TDCIPP. During exposure and after exposure, effects at the molecular, histological, individual and population levels were examined. Multigenerational exposure to 300 or 3000 ng TDCIPP/L for 60 days significantly decreased numbers of individuals, sizes of individuals, expressed as length and width of bodies, number of cilia, and depth and diameter of basal bodies of cilia, and up-regulated expressions of genes related to assembly and maintenance of cilia. Complete or partial recoveries of theoretical sizes of populations as well as sizes of individuals and expressions of genes were observed during the 60-day recovery period. Effects on number of cilia and depth and diameter of basal body of cilia were not reversible and could still be observed long after cease of TDCIPP exposure. Collectedly, and shown for the first time, multigenerational effects to T. thermophila were caused by exposure to environmentally relevant concentrations of TDCIPP. Also, there were multi-generational effects at the population level that were not caused by carry-over exposure to TDCIPP. The "permanent" alterations and their potential significance are discussed.
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Affiliation(s)
- Jing Li
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; Hubei Provincial Engineering Laboratory for Pond Aquaculture, China
| | - Xufa Ma
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China
| | - Guanyong Su
- Department of Chemistry, Carleton University, Ottawa, Ontario K1S 5B6, Canada
| | - John P Giesy
- Department of Veterinary Biomedical Sciences and Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada; School of Biological Sciences, University of Hong Kong, Hong Kong Special Administrative Region; State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210089, China
| | - Yuan Xiao
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Bingsheng Zhou
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Robert J Letcher
- Department of Chemistry, Carleton University, Ottawa, Ontario K1S 5B6, Canada
| | - Chunsheng Liu
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; Collaborative Innovation Center for Efficient and Health Production of Fisheries in Hunan Province, Hunan, Changde 415000, China.
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20
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Greaves AK, Su G, Letcher RJ. Environmentally relevant organophosphate triesters in herring gulls: In vitro biotransformation and kinetics and diester metabolite formation using a hepatic microsomal assay. Toxicol Appl Pharmacol 2016; 308:59-65. [DOI: 10.1016/j.taap.2016.08.007] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 07/29/2016] [Accepted: 08/09/2016] [Indexed: 12/18/2022]
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21
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Crump D, Chiu S, Williams KL. Bisphenol S alters embryonic viability, development, gallbladder size, and messenger RNA expression in chicken embryos exposed via egg injection. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2016; 35:1541-9. [PMID: 26606162 DOI: 10.1002/etc.3313] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 11/14/2015] [Accepted: 11/23/2015] [Indexed: 05/22/2023]
Abstract
Amid concerns about the toxicological effects and environmental prevalence of bisphenol A (BPA), efforts to find suitable, safer replacement alternatives are essential. Bisphenol S (BPS) is a potential chemical substitute for BPA; however, few studies are available confirming that it has a more desirable ecotoxicological profile. In the present study, BPS was injected into the air cell of unincubated, fertilized chicken embryos at 6 concentrations ranging from 0 μg/g to 207 μg/g egg to determine effects on pipping success, development, hepatic messenger ribonucleic acid (mRNA) expression, thyroid hormone levels, and circulating bile acid concentrations. Concentrations of BPS increased in a dose-dependent manner in whole-embryo homogenates, and exposure to the highest dose, 207 μg/g, resulted in decreased pipping success (estimated median lethal dose = 279 μg/g; 95% confidence interval = 161-486 μg/g). Exposure to BPS also reduced growth metrics including embryo mass and tarsus length, whereas the most pronounced phenotypic effect was the concentration-dependent, significant increase in gallbladder size at concentrations ≥52.8 μg/g. These adverse phenotypic outcomes were associated with the modulation of gene targets from a chicken ToxChip polymerase chain reaction array, which are involved with xenobiotic metabolism, lipid homeostasis, bile acid synthesis, and the thyroid hormone pathway. Expression levels of 2 estrogen-responsive genes, apolipoprotein II and vitellogenin, were too low at the sampling time point assessed (i.e., pipping embryos) to quantify changes, and no effects were observed on circulating free thyroxine or bile acid concentrations. The present study provides novel, whole-animal toxicological data for a BPA replacement alternative that is not well characterized. Environ Toxicol Chem 2016;35:1541-1549. © 2015 SETAC.
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Affiliation(s)
- Doug Crump
- National Wildlife Research Centre, Environment and Climate Change Canada, Ottawa, Ontario, Canada
| | - Suzanne Chiu
- National Wildlife Research Centre, Environment and Climate Change Canada, Ottawa, Ontario, Canada
| | - Kim L Williams
- National Wildlife Research Centre, Environment and Climate Change Canada, Ottawa, Ontario, Canada
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22
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Zheng X, Xu F, Luo X, Mai B, Covaci A. Phosphate flame retardants and novel brominated flame retardants in home-produced eggs from an e-waste recycling region in China. CHEMOSPHERE 2016; 150:545-550. [PMID: 26460270 DOI: 10.1016/j.chemosphere.2015.09.098] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 09/23/2015] [Accepted: 09/28/2015] [Indexed: 06/05/2023]
Abstract
Phosphate flame retardants (PFRs) and novel brominated flame retardants (NBFRs) (2-ethylhexyl-2,3,4,5-tetrabromo-benzoate (EH-TBB) and bis-(2-ethylhexyl)-3,4,5,6-tetrabromo-phthalate (BEH-TEBP)) were measured in free-range chicken eggs from three e-waste recycling sites and a negative control site located in Guangdong province, Southern China. BEH-TEBP, tris-(chloroethyl)-phosphate (TCEP), tris-(chloropropyl)-phosphate (∑TCPP, two isomers) and tris-(1,3-dichloroisopropyl)-phosphate (TDCIPP) were detected in more than 50% of eggs samples with low concentrations. The median values of BEH-TEBP and total PFRs were 0.17-0.46 ng/g ww (wet weight) and 1.62-2.59 ng/g ww in eggs from the e-waste sites, respectively. The results indicate that EH-TBB, BEH-TEBP and PFRs are less persistent and bioaccumulative than polybrominated diphenyl ethers (PBDEs) in chicken eggs, and possibly also in other bio-matrices. Triphenyl phosphate (TPHP) were identified in albumen with higher frequencies, but at similar concentrations compared to yolk, while BEH-TEBP was mainly detected in yolk. The estimated daily intake (EDI) of BEH-TEBP and total PFRs from consumption of chicken eggs ranged from 0.03 to 0.09 and 0.32-0.52 ng/kg bw/day for adults, and 0.20-0.54 and 1.89-3.02 ng/kg bw/day for children in e-waste sites, respectively. Indoor dust ingestion seems to be a more important pathway for the intake of these FRs, while egg consumption is probably a more important exposure pathway for PBDEs.
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Affiliation(s)
- Xiaobo Zheng
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Chinese Academy of Sciences, Guangzhou, 510640, People's Republic of China; Toxicological Centre, University of Antwerp, Universiteitsplein 1, 2610, Wilrijk, Belgium; College of Natural Resources and Environment, South China Agricultural University, Guangzhou, 510642, People's Republic of China
| | - Fuchao Xu
- Toxicological Centre, University of Antwerp, Universiteitsplein 1, 2610, Wilrijk, Belgium
| | - Xiaojun Luo
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Chinese Academy of Sciences, Guangzhou, 510640, People's Republic of China.
| | - Bixian Mai
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Chinese Academy of Sciences, Guangzhou, 510640, People's Republic of China
| | - Adrian Covaci
- Toxicological Centre, University of Antwerp, Universiteitsplein 1, 2610, Wilrijk, Belgium.
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Crump D, Farhat A, Chiu S, Williams KL, Jones SP, Langlois VS. Use of a Novel Double-Crested Cormorant ToxChip PCR Array and the EROD Assay to Determine Effects of Environmental Contaminants in Primary Hepatocytes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:3265-3274. [PMID: 26894911 DOI: 10.1021/acs.est.5b06181] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In vitro screening tools and 'omics methods are increasingly being incorporated into toxicity studies to determine mechanistic effects of chemicals and mixtures. To date, the majority of these studies have been conducted with well-characterized laboratory animal models. In the present study, well-established methods developed for chicken embryonic hepatocyte (CEH) studies were extended to a wild avian species, the double-crested cormorant (DCCO; Phalacrocorax auritus), in order to compare the effects of several environmental contaminants on cytotoxicity, ethoxyresorufin O-deethylase (EROD) activity, and mRNA expression. Five organic flame retardants and one plasticizer decreased cormorant hepatocyte viability in a similar manner to that observed in previous studies with CEH. EROD activity was induced in a concentration-dependent manner following exposure to two dioxin-like chemicals and the calculated EC50 values were concordant with domestic avian species from similar species sensitivity categories. Transcriptomic effects were determined using a novel DCCO PCR array, which was designed, constructed and validated in our laboratory based on a commercially available chicken PCR array. The DCCO array has 27 target genes covering a wide range of toxicity pathways. Gene profiles were variable among the 10 chemicals screened; however, good directional concordance was observed with regard to results previously obtained in CEH. Overall, the application of well-established methods (i.e., CEH and chicken PCR array) to the double-crested cormorant demonstrated the portability of the techniques to an indicator species of ecological relevance.
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Affiliation(s)
- Doug Crump
- Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University , Ottawa, ON Canada K1A 0H3
| | - Amani Farhat
- Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University , Ottawa, ON Canada K1A 0H3
| | - Suzanne Chiu
- Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University , Ottawa, ON Canada K1A 0H3
| | - Kim L Williams
- Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University , Ottawa, ON Canada K1A 0H3
| | - Stephanie P Jones
- Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University , Ottawa, ON Canada K1A 0H3
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24
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Zhu Y, Ma X, Su G, Yu L, Letcher RJ, Hou J, Yu H, Giesy JP, Liu C. Environmentally Relevant Concentrations of the Flame Retardant Tris(1,3-dichloro-2-propyl) Phosphate Inhibit Growth of Female Zebrafish and Decrease Fecundity. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:14579-87. [PMID: 26512412 DOI: 10.1021/acs.est.5b03849] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Bioconcentrations of tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) in brain, gonad, and liver as well as effects on fecundity and development of zebrafish (Danio rerio) were determined. Zebrafish (1-month old) were exposed to environmentally relevant concentrations of 29 ± 2.1, 600 ± 21, or 6300 ± 130 ng TDCIPP/L. After 120 days of exposure, TDCIPP accumulated in the brain, gonad, and liver with bioconcentration factors of 460, 38, and 87 in females and 26, 55, and 110 in males, respectively. TDCIPP accumulated to a greater extent in brains of females than those of males. Exposure to 6300 ± 130 ng TDCIPP/L resulted in significantly (P < 0.05) fewer eggs being produced, but the histology of the gonad, plasma concentrations of estradiol and 11-ketotestosterone, and expression of genes involved in hypothalamic-pituitary-gonadal-liver axis were not significantly (P > 0.05) different between individuals exposed to TDCIPP and the unexposed control fish. Exposure to TDCIPP resulted in shorter body length, lighter body mass, and lower gonadal-somatic index in females. These effects were possibly due to down-regulation of expression of genes along the growth hormone/insulin-like growth factor (GH/IGF) axis. Correlations between the production of eggs and developmental parameters or expression of genes along the GH/IGF axis further suggested that environmentally relevant concentrations of TDCIPP could have adverse effects on reproduction, possibly due to the inhibition of the growth of females.
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Affiliation(s)
- Ya Zhu
- College of Fisheries, Huazhong Agricultural University , Wuhan 430070, China
| | - Xufa Ma
- College of Fisheries, Huazhong Agricultural University , Wuhan 430070, China
| | - Guanyong Su
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University , Nanjing 210089, China
- Department of Chemistry, Carleton University , Ottawa, Ontario K1S 5B6, Canada
| | - Liqin Yu
- College of Fisheries, Huazhong Agricultural University , Wuhan 430070, China
| | - Robert J Letcher
- Department of Chemistry, Carleton University , Ottawa, Ontario K1S 5B6, Canada
| | - Jie Hou
- College of Fisheries, Huazhong Agricultural University , Wuhan 430070, China
| | - Hongxia Yu
- Department of Chemistry, Carleton University , Ottawa, Ontario K1S 5B6, Canada
| | - John P Giesy
- Department of Chemistry, Carleton University , Ottawa, Ontario K1S 5B6, Canada
- Department of Veterinary Biomedical Sciences and Toxicology Centre, University of Saskatchewan , Saskatoon, Saskatchewan S7N 5B3, Canada
- Department of Zoology and Centre for Integrative Toxicology, Michigan State University , East Lansing, Michigan 48824, United States
| | - Chunsheng Liu
- College of Fisheries, Huazhong Agricultural University , Wuhan 430070, China
- Collaborative Innovation Center for Efficient and Health Production of Fisheries in Hunan Province, Hunan Agriculture University , Changsha 410128, China
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25
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Su G, Letcher RJ, Yu H. Determination of organophosphate diesters in urine samples by a high-sensitivity method based on ultra high pressure liquid chromatography-triple quadrupole-mass spectrometry. J Chromatogr A 2015; 1426:154-60. [DOI: 10.1016/j.chroma.2015.11.018] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 10/14/2015] [Accepted: 11/05/2015] [Indexed: 12/19/2022]
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26
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Li H, Su G, Zou M, Yu L, Letcher RJ, Yu H, Giesy JP, Zhou B, Liu C. Effects of Tris(1,3-dichloro-2-propyl) Phosphate on Growth, Reproduction, and Gene Transcription of Daphnia magna at Environmentally Relevant Concentrations. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:12975-83. [PMID: 26422752 DOI: 10.1021/acs.est.5b03294] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The synthetic flame retardant tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) has been frequently detected in natural waters, and its maximum concentration ever reported is 377 ng/L. However, information on the adverse effects of environmentally relevant concentrations of TDCIPP on aquatic organisms are totally unknown. In this study, <12-h old water fleas, D. magna, were exposed to concentrations of 0, 65±7.1, 550±33, or 6500±1400 ng/L TDCIPP, and dose- and time-dependent effects on reproduction and development were evaluated. Sequences of genes of D. magna were obtained from the National Center for Biotechnology Information and were used to develop PCR arrays for D. magna. Arrays were then used to study transcriptional responses of D. magna to TDCIPP. Exposure to environmentally relevant concentrations of TDCIPP significantly decreased fecundity as well as length of F0 and F1 generations. Transcriptional responses showed that, of the 155 genes tested, expressions of 57 genes were significantly changed, and some changes occurred following exposure to environmentally relevant concentrations (i.e., 65±7.1 and 550±23 ng/L). Furthermore, pathways related to protein synthesis and metabolism and endocytosis were considered to be significantly affected in a dose- and time-dependent manner and might be responsible for TDCIPP-induced reproductive and developmental toxicities.
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Affiliation(s)
- Han Li
- College of Fisheries, Huazhong Agricultural University , Wuhan 430070, China
| | - Guanyong Su
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University , Nanjing 210089, China
- Department of Chemistry, Carleton University , Ottawa, Ontario K1S 5B6, Canada
| | - Ming Zou
- College of Fisheries, Huazhong Agricultural University , Wuhan 430070, China
| | - Liqin Yu
- College of Fisheries, Huazhong Agricultural University , Wuhan 430070, China
| | - Robert J Letcher
- Department of Chemistry, Carleton University , Ottawa, Ontario K1S 5B6, Canada
| | - Hongxia Yu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University , Nanjing 210089, China
| | - John P Giesy
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University , Nanjing 210089, China
- Department of Veterinary Biomedical Sciences and Toxicology Centre, University of Saskatchewan , Saskatoon, Saskatchewan S7N 5B3, Canada
- Department of Zoology and Centre for Integrative Toxicology, Michigan State University , East Lansing, Michigan 48824, United States
| | - Bingsheng Zhou
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Science , Wuhan 430072, China
| | - Chunsheng Liu
- College of Fisheries, Huazhong Agricultural University , Wuhan 430070, China
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27
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Su G, Letcher RJ, Moore JN, Williams LL, Martin PA, de Solla SR, Bowerman WW. Spatial and temporal comparisons of legacy and emerging flame retardants in herring gull eggs from colonies spanning the Laurentian Great Lakes of Canada and United States. ENVIRONMENTAL RESEARCH 2015; 142:720-730. [PMID: 26406977 DOI: 10.1016/j.envres.2015.08.018] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 08/13/2015] [Accepted: 08/16/2015] [Indexed: 06/05/2023]
Abstract
In the Laurentian Great Lakes basin of North America, an increasing number of chemicals of emerging concern (CECs) are being investigated, including legacy and replacement flame retardants (FRs). In the present study, 14 polybrominated diphenyl ethers (PBDEs), 23 non-PBDEs halogenated FRs (NPHFRs) and 16 organophosphate ester FRs (OPE-FRs) were analyzed in 100 individual eggs collected in 2012 and 2013 and in 15 egg pools of herring gulls collected in 2012 from 20 colonies across the entire Laurentian Great Lakes basin. For CEC-FRs in eggs from all colonies, 14 PBDEs, 12 NPHFRs and 9 OPE-FRs were quantifiable in at least one of the 115 analyzed samples. The mean sum PBDE (Σ14PBDE) concentrations ranged from 244 to 657 ng/g wet weight (ww), and on average were 1-2 orders of magnitude greater than the Σ12NPHFR concentrations (13.8-35.6 ng/g ww), and 2-3 orders of magnitude greater than Σ9OPE-FR concentrations (0.31-2.14 ng/g ww). Mean Σ14PBDE and sum of syn- and anti-Dechlorane Plus isomer (Σ2DDC-CO) concentrations in eggs from colonies within Laurentian Great Lakes Areas of Concern (AOCs) were in most cases greater than in eggs from nearby colonies outside of AOCs. Comparing CEC-FR concentrations in eggs collected in 2012-2013 to those previously measured in eggs collected approximately 7 years earlier (2006 and 2008) showed that Σ7PBDE (BDE-28, -47, -100, -99, -154,-153 and -183) mean concentrations in eggs from 6 colonies were approximately 30% less than they were in eggs from the same colonies from the earlier time period, whereas 3 current-use FR (BDE-209, HBCDD and Σ2DDC-CO) concentrations were significantly greater (p<0.05) than previously measured. Between 2006 and 2013 there were significant changes in individual PBDE patterns for BDE-71, -138, -153, -203, -206 and -207. Among all of the examined CEC-FRs, concentrations of Σ4PBDE (BDE-47, -99, -100 and -153) and HBCDD in gull eggs from all colonies were greater than or comparable to their lowest observed effect concentrations (LOECs) based on in ovo egg injection studies. Overall, the current profiles of a broad suite of FRs in Laurentian Great Lakes herring gull eggs highlights the need to better understand e.g., exposure-effect implications and metabolism of FRs, i.e. OPE-FRs, and emphasizes the importance of continued monitoring of CEC-FRs whose concentrations appear to be increasing, including BDE-209, HBCDD and DDC-COs.
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Affiliation(s)
- Guanyong Su
- Ecotoxicology and Wildlife Health Division, Wildlife and Landscape Directorate, Science and Technology Branch, Environment Canada, National Wildlife Research Center, Carleton University, Ottawa, ON, Canada; Department of Chemistry, Carleton University, Ottawa, ON, Canada K1S 5B6
| | - Robert J Letcher
- Ecotoxicology and Wildlife Health Division, Wildlife and Landscape Directorate, Science and Technology Branch, Environment Canada, National Wildlife Research Center, Carleton University, Ottawa, ON, Canada; Department of Chemistry, Carleton University, Ottawa, ON, Canada K1S 5B6.
| | - Jeremy N Moore
- US Fish and Wildlife Service, East Lansing Ecological Services Field Office, East Lansing, MI, USA
| | - Lisa L Williams
- US Fish and Wildlife Service, East Lansing Ecological Services Field Office, East Lansing, MI, USA
| | - Pamela A Martin
- Ecotoxicology and Wildlife Health Division, Wildlife and Landscape Directorate, Science and Technology Branch, Environment Canada, Burlington, ON, Canada
| | - Shane R de Solla
- Ecotoxicology and Wildlife Health Division, Wildlife and Landscape Directorate, Science and Technology Branch, Environment Canada, Burlington, ON, Canada
| | - William W Bowerman
- Department of Environmental Science and Technology, University of Maryland, College Park, MD, USA
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28
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Xu T, Wang Q, Shi Q, Fang Q, Guo Y, Zhou B. Bioconcentration, metabolism and alterations of thyroid hormones of Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) in Zebrafish. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2015; 40:581-6. [PMID: 26356387 DOI: 10.1016/j.etap.2015.08.020] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2015] [Revised: 08/10/2015] [Accepted: 08/16/2015] [Indexed: 05/20/2023]
Abstract
Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) is an organophosphate widely used as a flame retardant, and has frequently been detected in the environment and biota. The present study investigates the bioconcentration and metabolism of TDCPP in fish. Zebrafish embryos (from 2h post-fertilization) were exposed to TDCPP (0, 4, 20 and 100μg/L) for six months. Exposure to TDCPP significantly induced phase I metabolic enzymes 7-ethoxyresorufin O-deethylase (EROD) and 7-methoxyresorufin O-demethylase (MROD) in fish. The mRNA expression of genes related to Phase I and II metabolic enzymes, such as cyp1a1, cyp1b1, cyp1c1 and ugt1ab were also significantly upregulated. Exposure to TDCPP significantly reduced plasma thyroxine (T4) and 3,5,3'-triiodothyronine (T3) levels in females. Chemicals analysis indicated significant levels of TDCPP and its metabolite, bis (1,3-dichloro-2-propyl) phosphate (BDCPP), in the liver. The present study reveals that exposure to low concentrations of TDCPP can cause bioconcentration in fish, and TDCPP can be readily metabolized in liver.
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Affiliation(s)
- Tao Xu
- Puai Hospital, Huazhong University of Science and Technology, Wuhan 430033, China
| | - Qiangwei Wang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou 310058, China.
| | - Qipeng Shi
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Qi Fang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Yongyong Guo
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Bingsheng Zhou
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
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Zhang J, Williams TD, Chipman JK, Viant MR. Defensive and adverse energy-related molecular responses precede tris (1, 3-dichloro-2-propyl) phosphate cytotoxicity. J Appl Toxicol 2015; 36:649-58. [DOI: 10.1002/jat.3194] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 05/12/2015] [Accepted: 05/18/2015] [Indexed: 12/17/2022]
Affiliation(s)
- Jinkang Zhang
- School of Biosciences; University of Birmingham; Birmingham B15 2TT UK
| | | | - James K. Chipman
- School of Biosciences; University of Birmingham; Birmingham B15 2TT UK
| | - Mark R. Viant
- School of Biosciences; University of Birmingham; Birmingham B15 2TT UK
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Wang Q, Lai NLS, Wang X, Guo Y, Lam PKS, Lam JCW, Zhou B. Bioconcentration and transfer of the organophorous flame retardant 1,3-dichloro-2-propyl phosphate causes thyroid endocrine disruption and developmental neurotoxicity in zebrafish larvae. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:5123-32. [PMID: 25826601 DOI: 10.1021/acs.est.5b00558] [Citation(s) in RCA: 181] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Organophosphate flame retardants are emerging environmental contaminants, although knowledge of their health risks is limited. Here, thyroid hormone homeostasis and neuronal development was studied in the progeny of adult zebrafish exposed to tris(1,3-dichloro-2-propyl) phosphate (TDCPP). Adult zebrafish were exposed to TDCPP (0, 4, 20, and 100 μg/L) for 3 months. Increased generation of reactive oxygen species and reduced survival rates was observed in exposed F1 larvae. We also observed a significant decrease in plasma thyroxine and 3,5,3'-triiodothyronine levels in F0 females and F1 eggs/larvae. The mRNA and protein expression of factors associated with neuronal development (e.g., α1-tubulin, myelin basic protein, and synapsin IIa) were significantly downregulated in exposed F1 larvae, as was the level of the neurotransmitters dopamine, serotonin, gamma amino butyric acid, and histamine. Larval locomotion was significantly decreased in exposed fish, but there was no effect on acetylcholinesterase activity. Bioconcentration of TDCPP was observed in F0 fish. TDCPP was also detected in F1 eggs following parental exposure, indicating maternal transfer of this compound. This study uniquely shows that TDCPP can be transferred to the offspring of exposed adults, causing thyroid endocrine disruption and developmental neurotoxicity.
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Affiliation(s)
- Qiangwei Wang
- †State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
- ‡University of Chinese Academy of Sciences, Beijing 100049, China
| | - Nelson Lok-Shun Lai
- §State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
- ∥Research Centre for the Oceans and Human Health, Shenzhen Key Laboratory for Sustainable Use of Marine Biodiversity, City University of Hong Kong Shenzhen Research Institute Building, Shenzhen, Guangdong 518057, China
- ⊥Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Xianfeng Wang
- †State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
- ‡University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yongyong Guo
- †State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
| | - Paul Kwan-Sing Lam
- §State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
- ∥Research Centre for the Oceans and Human Health, Shenzhen Key Laboratory for Sustainable Use of Marine Biodiversity, City University of Hong Kong Shenzhen Research Institute Building, Shenzhen, Guangdong 518057, China
- ⊥Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - James Chung-Wah Lam
- ∥Research Centre for the Oceans and Human Health, Shenzhen Key Laboratory for Sustainable Use of Marine Biodiversity, City University of Hong Kong Shenzhen Research Institute Building, Shenzhen, Guangdong 518057, China
| | - Bingsheng Zhou
- †State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
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Su G, Crump D, Letcher RJ, Kennedy SW. Rapid in vitro metabolism of the flame retardant triphenyl phosphate and effects on cytotoxicity and mRNA expression in chicken embryonic hepatocytes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:13511-9. [PMID: 25350880 DOI: 10.1021/es5039547] [Citation(s) in RCA: 160] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The organophosphate flame retardant, triphenyl phosphate (TPHP), has been detected with increasing frequency in environmental samples and its primary metabolite is considered to be diphenyl phosphate (DPHP). Information on the adverse effects of these compounds in avian species is limited. Here, we investigate the effects of TPHP and DPHP on cytotoxicity and mRNA expression, as well as in vitro metabolism of TPHP, by use of a chicken embryonic hepatocyte (CEH) screening assay. After 36 h of exposure, CEH cytotoxicity was observed following exposure to >10 μM TPHP (LC50 = 47 ± 8 μM), whereas no significant cytotoxic effects were observed for DPHP concentrations up to 1000 μM. Using a custom chicken ToxChip polymerase chain reaction (PCR) array, the number of genes altered by 10 μM DPHP (9 out of 27) was greater than that by 10 μM TPHP (4 out of 27). Importantly, 4 of 6 genes associated with lipid/cholesterol metabolism were significantly dysregulated by DPHP, suggesting a potential pathway of importance for DPHP toxicity. Rapid degradation of TPHP was observed in CEH exposed to 10 μM, but the resulting concentration of DPHP accounted for only 17% of the initial TPHP dosing concentration. Monohydroxylated-TPHP (OH-TPHP) and two (OH)2-TPHP isomers were identified in TPHP-exposed CEH, and concentrations of these metabolites increased over 0 to 36 h. Overall, this is the first reported evidence that across 27 toxicologically relevant genes, DPHP altered more transcripts than its precursor, and that TPHP is also metabolized via a hydroxylation pathway in CEH.
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Affiliation(s)
- Guanyong Su
- Environment Canada, National Wildlife Research Centre, Carleton University , Ottawa, Ontario K1A 0H3, Canada
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