Disruption of the hypothalamic-pituitary-thyroid axis in zebrafish embryo-larvae following waterborne exposure to BDE-47, TBBPA and BPA
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香港中文大學研究人員

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摘要We performed waterborne exposures of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), tetrabromobisphenol A (TBBPA) or bisphenol A (BPA) on zebrafish (Danio rerio) embryo-larvae and quantitatively measured the expression of genes belonging to the hypothalamic-pituitary-thyroid (HPT) axis to assess for adverse thyroid function. For analysis on the effects of BDE-47, TBBPA and BPA on the hypothalamic-pituitary-thyroid genes, zebrafish embryo-larvae were acutely exposed to lethal concentrations of the chemical agents in order to determine the 96 h-LC50 (96 h lethal median concentration) and 96 h-EC50 (96 h effective median concentration) values. Further exposures at sub-lethal concentrations were then carried out and total RNA samples were extracted to quantify the mRNA expression levels of the genes of interest. In larvae, BDE-47 was found to have significantly induced many genes of interest, namely thyroglobulin, thyroid peroxidase, thyroid receptors alpha and beta, thyroid stimulating hormone, and transthyretin. TBBPA only significantly induced three genes of interest (thyroid receptor alpha, thyroid stimulating hormone, and transthyretin) while BPA only induced thyroid stimulating hormone. In embryos, BDE-47 significantly induced the sodium iodide symporter and thyroid stimulating hormone. TBBPA significantly induced thyroid receptor a and thyroid stimulating hormone, while BPA did not significantly induce any of the genes. Most genes were only induced at the 75% 96 h-LC50 or 96 h-EC50 value: however, thyroid peroxidase and thyroid stimulating hormone demonstrated upregulation in a level as little as the 10% 96 h-LC50 value. The present study provides a new set of data on zebrafish mRNA induction of hypothalamic-pituitary-thyroid genes from exposure to BDE-47, TBBPA, or BPA. This information would serve useful for elucidating the toxicological mechanism of brominated flame retardants, assessing appropriate safety levels in the environment for these compounds, as well as serve as a reference for other man-made contaminants. (C) 2011 Elsevier B.V. All rights reserved.
著者Chan WK, Chan KM
期刊名稱Aquatic Toxicology
出版年份2012
月份2
日期1
卷號108
出版社Elsevier
頁次106 - 111
國際標準期刊號0166-445X
電子國際標準期刊號1879-1514
語言英式英語
關鍵詞Brominated flame retardant; Gene induction; Hypothalamic-pituitary-thyroid axis; Real-time polymerase chain reaction; Zebrafish
Web of Science 學科類別Marine & Freshwater Biology; MARINE & FRESHWATER BIOLOGY; Toxicology; TOXICOLOGY

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