PUBLICATION

Bioaccumulation, biotransformation and toxicity of BDE-47, 6-OH-BDE-47 and 6-MeO-BDE-47 in early life-stages of zebrafish (Danio rerio)

Authors
Liu, H., Tang, S., Zheng, X., Zhu, Y., Ma, Z., Liu, C., Hecker, M., Saunders, D.M., Giesy, J.P., Zhang, X., Yu, H.
ID
ZDB-PUB-150108-6
Date
2015
Source
Environmental science & technology   49(3): 1823-33 (Journal)
Registered Authors
Keywords
none
MeSH Terms
  • Animals
  • Anisoles*/pharmacokinetics
  • Anisoles*/toxicity
  • Biotransformation
  • Embryo, Nonmammalian/drug effects
  • Embryo, Nonmammalian/metabolism
  • Endocrine Disruptors/pharmacokinetics
  • Endocrine Disruptors/toxicity
  • Flame Retardants*/pharmacokinetics
  • Flame Retardants*/toxicity
  • Gene Expression Regulation, Developmental/drug effects
  • Halogenated Diphenyl Ethers*/pharmacokinetics
  • Halogenated Diphenyl Ethers*/toxicity
  • Larva/drug effects
  • Larva/genetics
  • Larva/metabolism
  • Polybrominated Biphenyls*/pharmacokinetics
  • Polybrominated Biphenyls*/toxicity
  • Receptors, Androgen/genetics
  • Receptors, Aryl Hydrocarbon/genetics
  • Receptors, Estrogen/genetics
  • Receptors, Glucocorticoid/genetics
  • Receptors, Mineralocorticoid/genetics
  • Receptors, Thyroid Hormone/genetics
  • Water Pollutants, Chemical/pharmacokinetics
  • Water Pollutants, Chemical/toxicity
  • Zebrafish/embryology
  • Zebrafish/genetics
  • Zebrafish/metabolism
PubMed
25565004 Full text @ Env. Sci. Tech.
CTD
25565004
Abstract
2,2',4,4'-Tetrabromodiphenyl ether (BDE-47), 6-hydroxy-tetrabromodiphenyl ether (6-OH-BDE-47), and 6-methoxy-tetrabromodiphenyl ether (6-MeO-BDE-47) are the most detected congeners of polybrominated diphenyl ethers (PBDEs), OH-BDEs, and MeO-BDEs, respectively, in aquatic organisms. Although it has been demonstrated that BDE-47 can interfere with certain endocrine functions that are mediated through several nuclear hormone receptors (NRs), most of these findings were from mammalian cell lines exposed in vitro. In the present study, embryos and larvae of zebrafish were exposed to BDE-47, 6-OH-BDE-47, and 6-MeO-BDE-47 to compare their accumulation, biotransformation, and bioconcentration factors (BCF) from 4 to 120 hpf. In addition, effects on expression of genes associated with eight different pathways regulated by NRs were investigated at 120 hpf. 6-MeO-BDE-47 was most bioaccumulated and 6-OH-BDE-47, which was the most potent BDE, was least bioaccumulated. Moreover, the amount of 6-MeO-BDE-47, but not BDE-47, transformed to 6-OH-BDE-47 increased in a time-dependent manner, approximately 0.01%, 0.04%, and 0.08% at 48, 96, and 120 hpf, respectively. Expression of genes regulated by the aryl hydrocarbon receptor (AhR), estrogen receptor (ER), and mineralocorticoid receptor (MR) was affected in larvae exposed to 6-OH-BDE-47, while genes regulated by AhR, ER, and the glucocorticoid receptor (GR) were altered in larvae exposed to BDE-47. The greatest effect on expression of genes was observed in larvae exposed to 6-MeO-BDE-47. Specifically, 6-MeO-BDE-47 affected the expression of genes regulated by AhR, ER, AR, GR, and thyroid hormone receptor alpha (TRα). These pathways were mostly down-regulated at 2.5 μM. Taken together, these results demonstrate the importance of usage of an internal dose to assess the toxic effects of PBDEs. BDE-47 and its analogs elicited distinct effects on expression of genes of different hormone receptor-mediated pathways, which have expanded the knowledge of different mechanisms of endocrine disrupting effects in aquatic vertebrates. Because some of these homologues are natural products assessments of risks of anthropogenic PBDE need to be made against the background of concentrations from naturally occurring products. Even though PBDEs are being phased out as flame retardants, the natural products remain.
Genes / Markers
Figures
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping