title: Impact of co-exposure with lead and decabromodiphenyl ether (BDE-209) on thyroid function in zebrafish larvae.
abstract: Polybrominated diphenyl ethers (PBDEs) and metals are the main contaminants at waste electrical and electronic equipment ("e-waste") recycling sites. However, the potential environmental health effects of mixtures of PBDEs and metals are not known. We investigated co-exposure of lead (Pb) with decabromodiphenyl ether (BDE-209) on thyroid function in zebrafish larvae. Seven groups of embryos/larvae of zebrafish were treated with Pb (0, 2, 5, 10, 15, 20, and 30 μg/L), six groups were exposed to BDE-209 (0, 50, 100, 200, 400, and 800 μg/L), and nine groups of zebrafish larvae were treated with Pb and BDE-209 (5, 10, and 20 μg/L Pb; 50, 100, and 200 μg/L BDE-209). Embryos/larvae were exposed from 2h post-fertilization (hpf) until 144 hpf, and thyroid hormone (TH) content measured. Pb exposure significantly decreased whole-body TH contents (triiodothyroxine (T3) and thyroxine (T4)) but BDE-209 exposure significantly increased T3 and T4 levels. Pb or BDE-209 treatment alone caused a predicted downregulation of TH transport (i.e., expression of the mRNA or proteins of transthyretin). Chemical analyses showed Pb uptake to be increased by BDE-209, but BDE-209 bioconcentration was decreased and the ability to metabolize BDE-209 was reduced in the presence of Pb. We also found that a mixture of the two chemicals had a synergistic effect on TH levels in zebrafish.
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Biran
authors.initials: B
authors.lastname: Zhu
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Qiangwei
authors.initials: Q
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Xianfeng
authors.initials: X
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China. Electronic address: bszhou@ihb.ac.cn.
authors.forename: Bingsheng
authors.initials: B
authors.lastname: Zhou
mesh_terms: D000818:Animals; D004357:Drug Synergism; D005786:Gene Expression Regulation / Q000187:drug effects; D055768:Halogenated Diphenyl Ethers / Q000378:metabolism / Q000633:toxicity*; D007814:Larva / Q000187:drug effects; D007854:Lead / Q000378:metabolism / Q000633:toxicity*; D011228:Prealbumin / Q000235:genetics; D013961:Thyroid Gland / Q000187:drug effects*; D013963:Thyroid Hormones / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000378:metabolism / Q000633:toxicity*; D015027:Zebrafish / Q000502:physiology*
chemical_list: D055768:Halogenated Diphenyl Ethers; D011228:Prealbumin; D013963:Thyroid Hormones; D014874:Water Pollutants, Chemical; D007854:Lead; C010902:decabromobiphenyl ether
keywords: BDE-209; Co-exposure; Pb; Synergistic effects; Thyroid disruption; Thyroid hormones