Effects of BPZ and BPC on Oxidative Stress of Zebrafish under Different pH Conditions

To further understand the toxic effects of bisphenol Z (BPZ) and bisphenol C (BPC) on aquatic organisms, zebrafish (Danio rerio) were exposed to 0.02 mg/L BPZ and BPC mixed solution in the laboratory for 28 days. The impacts of BPZ and BPC on the activity of the antioxidant enzymes, expression of antioxidant genes, and estrogen receptor genes in zebrafish under different pH conditions were studied. The changes of glutathione peroxidase (GSH-Px), reduced glutathione (GSH), total superoxide dismutase (T-SOD), catalase (POD), and malondialdehyde (MDA) in the zebrafish were detected by spectrophotometry. The mRNA relative expression levels of CAT, GSH, SOD, ERa, and ERb1 in the experimental group were determined by fluorescence quantitative PCR. The results showed that SOD activity and MDA content were inhibited under different pH conditions, and the activities of GSH, GSH-Px, and POD were induced. The activities of POD and GSH induced in the neutral environment were stronger than those in an acidic and alkaline environment. The mRNA relative expression levels of SOD and GSH were consistent with the activities of SOD and GSH. The mRNA relative expression levels of CAT were induced more strongly in the neutral environment than in acidic and alkaline conditions, the mRNA relative expression levels of ERa were induced most weakly in a neutral environment, and the mRNA relative expression levels of ERb1 were inhibited the most in a neutral environment.