Graphene oxide mitigates endocrine disruption effects of bisphenol A on zebrafish at an early development stage

Development from embryos to larvae is an important life stage and impairments in this stage could affect the development and growth of fish. In this study, the endocrine disruption and developmental toxicities of bisphenol A (BPA) (50 and 500 μg/L) in the presence of graphene oxide (GO) (0.1 and 1 mg/L) were investigated on zebrafish embryos from 6 to 168 h post fertilization (hpf). BPA alone displayed significant endocrine disruption effects (increase in the estradiol (E2)/testosterone (T) ratio, vitellogenin (VTG) and estrogen receptor α (erα) in larvae), promoted embryos hatching and caused larvae malformation. There was a significant correlation between VTG level and erα expression, suggesting that erα played a vital role in VTG synthesis. However, all these adverse effects were alleviated distinctly in the presence of GO. GO formed a coating layer on the embryos chorion membrane, depressing absorption of BPA by the embryos. As a consequence, bioaccumulation of BPA in zebrafish co-exposed to GO and BPA decreased by >50% compared with the BPA single exposure group. Adsorption of BPA on GO might also make a partial contribution to the reduced accumulation of BPA in the larvae. The results demonstrated that GO could relieve the estrogenic and developmental effects of BPA on zebrafish in the early development stage.