Investigation on Sex Hormone-Disruption Effects of Two Novel Brominated Flame Retardants (DBDPE and BTBPE) in Male Zebrafish (Danio rerio) and Two Human Cell Lines (H295R and MVLN)

Decabromodiphenyl ethane (DBDPE) and 1,2-bis(2,4,6-tribromo-phenoxy) ethane (BTBPE) are novel brominated flame retardants (NBFRs) and have been detected in variety of environment and biota. Although sex endocrine-disrupting potential has been suggested in experimental studies, their adverse effects on sex steroid hormones and underlying mechanisms are largely unclear. The purpose of the present study is to investigate the sex hormone-disrupting effects of two NBFRs using in vivo and in vitro models together. For this, male zebrafish (Danio rerio) along with human adrenocortical carcinoma (H295R) and breast carcinoma (MVLN) cell lines were employed. In male zebrafish, 14-day exposure to DBDPE significantly increased 17β-estradiol (E2) concentrations. Disruption of sex hormone regulation was also suggested after exposure to BTBPE, i.e., the increasing trend of E2 levels, E2/11-ketotestosterone (11-KT) ratio, and estrogen receptor-alpha (erα) and erβ gene expression levels. In H295R cells, an E2/T ratio showed an increasing trend by DBDPE exposure, but transcriptions of major genes in steroidogenesis pathway were not affected. Taken together, our observation implies that two NBFRs could cause the sex hormone disruption potential in male zebrafish and H295R cells but probably not through alteration of steroidogenesis pathway.