Oxidative stress and DNA damage in common carp (Cyprinus carpio) exposed to the herbicide mesotrione.

The present study was undertaken to investigate the oxidative stress and genotoxic effects of the herbicide mesotrione in a common freshwater fish, Cyprinus carpio. These fish were exposed to environmentally relevant concentrations of mesotrione (1.8, 18 and 180 μg L) for 7, 14 and 28 days. Levels of reactive oxygen species (ROS), malondialdehyde (MDA), reduced glutathione (GSH), activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) were measured in the gill, liver and muscle, together with levels of DNA damage that occurred. After 28 days exposure, significant increases in SOD and CAT activity and ROS content were observed in all three tissues but only at the highest concentration of exposure (180 μg L). No obvious changes in MDA, GSH, GPx or GR were observed in all treatments during the experiment. Comet assays revealed that the highest concentration of mesotrione induced DNA damage to different tissues in the common carp, especially the liver after chronic exposure occurred. These results provide evidence that the oxidant-antioxidant and comet assay could be integrated into monitoring programs determining the toxicity of water pollutants.