Embryonic exposure to cis-bifenthrin enantioselectively induces the transcription of genes related to oxidative stress, apoptosis and immunotoxicity in zebrafish (Danio rerio)

Cis-bifenthrin (cis-BF) is used widely for agricultural and non-agricultural purpose. Thus, cis-BF is one of the most frequently detected insecticides in the aquatic ecosystem. As a chiral pesticide, the commercial cis-BF contained two enantiomers including 1R-cis-BF and 1S-cis-BF. However, the difference in inducing oxidative stress, apoptosis and immunotoxicity by the two enantiomers in zebrafish still remains unclear. In the present study, the zebrafish were exposed to environmental concentrations of cis-BF, 1R-cis-BF and 1S-cis-BF during the embryos developmental stage. We observed that the mRNA levels of the most genes related to oxidative stress, apoptosis and immunotoxicity including Cu/Zn-superoxide dismutase (Cu/Zn-Sod), catalase (Cat), P53, murine double minute 2 (Mdm2), B-cell lymphoma/leukaemia-2 gene (Bcl2), Bcl2 associated X protein (Bax), apoptotic protease activating factor-1 (Apaf1), Caspase 9 (Cas9), Caspase 3 (Cas3), interleukin-1 beta (IL-1β) and interleukin-8(Il-8) were much higher in 1S-cis-BF treated group than those in cis-BF or 1R-cis-BF treated ones, suggesting that 1S-cis-BF has higher risk to induced oxidative stress, apoptosis and immunotoxicity than 1R-cis-BF in zebrafish. The information presented in this study will help with elucidating the differences and environmental risk of the two enantiomers of cis-BF-induced toxicity in aquatic organisms.