PUBLICATION

Toxicity and accumulation of 6-OH-BDE-47 and newly synthesized 6,6'-diOH-BDE-47 in early life-stages of Zebrafish (Danio rerio)

Authors
Zhang, M., Zhao, F., Zhang, J., Shi, J., Tao, H., Ge, H., Guo, W., Liu, D., Cai, Z.
ID
ZDB-PUB-201103-3
Date
2020
Source
The Science of the total environment   763: 143036 (Journal)
Registered Authors
Keywords
Developmental delay, DiOH-PBDEs, Gene transcription, Thyroid hormone, Zebrafish
MeSH Terms
  • Animals
  • Embryo, Nonmammalian
  • Halogenated Diphenyl Ethers*/toxicity
  • Polybrominated Biphenyls
  • Zebrafish*
PubMed
33131876 Full text @ Sci. Total Environ.
Abstract
Dihydroxylated polybrominated diphenyl ethers (diOH-PBDEs) appear to be natural products or metabolites of PBDEs in some marine organisms, yet its toxicity is still largely unknown. With a newly lab-synthesized diOH-PBDE, 6,6'-dihydroxy-2,2',4'4'-tetrabromodiphenyl ether (6,6'-diOH-BDE-47) in hand, the present study has provided the first data set to compare 6-hydroxy-2,2',4'4'- tetrabromodiphenyl ether (6-OH-BDE-47) and 6,6'-diOH-BDE-47 for their acute toxicity and accumulation, and thyroid hormone levels in treated zebrafish larvae. By real time-PCR technique, transcripts of hypothalamic-pituitary-thyroid axis associated genes were also investigated in developing larvae at 96 h post fertilization (96 hpf). Apparently, 6,6'-diOH-BDE-47 was less toxic than that of 6-OH-BDE-47: 1) the 96-h LC50 (96-h median lethal concentration) of 6-OH-BDE-47 and 6,6'-diOH-BDE-47 were 235 nM and 516 nM, respectively; 2) although severe developmental delays and morphological deformities were observed in zebrafish larvae in high exposure doses, at the exposure concentration of 1-50 nM, the accumulated 6-OH-BDE-47 and 6,6'-diOH-BDE-47 is ranged between 226-2279 nmol/g and 123-539 nmol/g in treated larvae; and 3) for 6-OH-BDE-47, its bioconcentration factor (BCF) were 1.83- to 4.30-fold more than that of 6,6'-diOH-BDE-47, suggesting that the lower internal exposure concentration of 6,6'-diOH-BDE-47 may lead to lower toxicity. The increased thyroid hormone levels were recorded for 1 nM of 6-OH-BDE-47 and 20 nM of 6,6'-diOH-BDE-47, and the exposures both significantly increased thyroid gland-specific transcription of thyroglobulin gene, indicating an adverse effect associated with the HPT axis. Therefore, 6,6'-diOH-BDE-47, with lower toxicity compared to that of 6-OH-BDE-47, still possesses hazards and environmental risk.
Genes / Markers
Figures
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping