Thiamethoxam Induces Oxidative Stress and Antioxidant Response in Zebrafish (Danio Rerio) Livers

Thiamethoxam, a second-generation neonicotinoid insecticide, was found to be toxic to nontarget aquatic organisms. The purpose of this study was to investigate the toxicity of thiamethoxam (0.30, 1.25, and 5.00 mg/L) on zebrafish (Danio rerio) livers at the 7th, 14th, 21st, and 28th days. The reactive oxygen species (ROS), superoxide dismutase (SOD), catalase (CAT), glutathione-s-transferase (GST), malondialdehyde (MDA) content, and DNA damage were used to evaluate the toxic effects of thiamethoxam on zebrafish. Compared to control groups, ROS levels were ascended in the exposure period; SOD and CAT activities were dramatically increased during early exposure and then inhibited. GST activity only increased on days 28. MDA content was slightly elevated on days 21 and 28. Additionally, a clear dose-response relationship was found for DNA damage. In conclusion, thiamethoxam could induce oxidative stress and DNA damage on the exposed zebrafish. (C) 2015 Wiley Periodicals, Inc.