Diastereoisomer-specific effects of hexabromocyclododecanes on hepatic aryl hydrocarbon receptors and cytochrome P450s in zebrafish (Danio rerio). (August 2015)

• Record Type: Journal Article
• Authors: Du, Miaomiao; Fang, Chao; Qiu, Ling; Dong, Sijun; Zhang, Xian; Yan, Changzhou
• Is Part Of: Chemosphere. Volume 132(2015)
• Page Start: 24
• Page End: 31
• Publication Date: 2015-08
• Subjects: Hexabromocyclododecane -- Diastereoisomer -- Aryl hydrocarbon receptor -- Cytochrome P450; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2015.02.049
• Languages: English
• ISSNs: 0045-6535

Abstract

Highlights: We examined the effects of HBCDs on AHRs, CYPs and EROD activity. HBCDs affect AHRs, CYP1s and EROD activity in a diastereoisomer-specific manner. The effects of HBCDs on AHRs and CYP1s indicate isomer-specific toxic risk. Abstract: In order to elucidate the mechanism for diastereoisomer-specific toxicity and metabolism of hexabromocyclododecanes (HBCDs) in biota, zebrafish ( Danio rerio ) were exposed to different concentrations of individual HBCD diastereoisomers (α-, β- and γ-HBCD) in water for 7 and 21 d. We examined the gene expression of aryl hydrocarbon receptor (AHR) and cytochrome P450 (CYP), as well as ethoxyresorufin-O-deethylase (EROD) activity in zebrafish livers. Exposure to different HBCD diastereoisomers caused different expression of AHRs in zebrafish livers. For instance, 10 and 100 μg L −1 of α- and β-HBCD up-regulated the expressions of ahr1a and ahr1b in zebrafish liver, whereas 10 and 100 μg L − 1 of γ-HBCD down-regulated them after 7 d exposure. α-HBCD showed the most significant up-regulation of ahr1a and ahr1b expression, whereas γ-HBCD showed the most significant down-regulation of their expression among three HBCD diastereoisomers. Moreover, HBCDs could affect the expression of CYP1s as well as EROD activity in a gene-specific and diastereoisomer-specific manner. α-, β- and γ-HBCD inhibited cyp1a expression but enhanced the expression of cyp1b1 and cyp1c1. α-, β- and γ-HBCD showed different degrees of effect on the same CYP1 gene in a concentration-dependent way. The different effects of HBCD diastereoisomers on these genes we examined and EROD activity not only indicate diastereoisomer-specific toxic effect, but also in turn explain diastereoisomer-specific accumulation of HBCDs in zebrafish.