Antagonistic effects of multi-walled carbon nanotubes and BDE-47 in zebrafish (Danio rerio): Oxidative stress, apoptosis and DNA damage.

• BDE-47 induced development inhibition, oxidative stress and apoptosis in zebrafish. • Acute co-exposure BDE-47 and MWCNTs resulted in developmental toxicity in zebrafish. • BDE-47 and MWCNTs have an antagonistic effect on developing zebrafish. In natural environments, organisms are often exposed to several environmental pollutants at any one time, and the potential effects of such co-exposures on human and environmental health are of considerable concern. It is thought that multi-walled carbon nanotubes (MWCNTs) may interact with other pollutants in aquatic systems and induce considerably different effects compared with exposure to a single contaminant. The objective of this study was to evaluate the potential acute combined effects of mixtures of MWCNTs and 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) on embryonic development stages, oxidative stress, apoptosis and DNA damage in developing zebrafish (Danio rerio). The embryos were treated with BDE-47 (5, 10, and 50 μg/L) and MWCNTs (50 mg/L), either combined or individually, for 96 h. Following exposure, BDE-47 induced significant acute toxicity, while the MWCNTs exhibited slight toxicity. When compared with BDE-47-only exposure, the inhibited growth induced by BDE-47 was weakened in the presence of MWCNTs. Similarly, the levels of oxidative stress biomarkers (reactive oxygen species, superoxide dismutase, catalase activities and malondialdehyde), apoptosis (apoptosis rate, caspase-3 and caspase-9 activities) and DNA damage (comet assay and comet olive tails) decreased in the presence of MWCNTs compared to those exposed to BDE-47 alone. These results demonstrate that MWCNTs can weaken the developmental inhibition, oxidative stress, apoptosis and DNA damage induced by BDE-47 in the early stages of zebrafish development. [ABSTRACT FROM AUTHOR]