Relationship between genotoxicity and oxidative stress induced by mercury on common carp (Cyprinus carpio) tissues

Mercury is one of the most toxic metals in aquatic systems since it is able to induce neurobehavioral disorders as well as renal and gastrointestinal tract damage. The common carp Cyprinus carpio is an important species from both an ecological and economic viewpoint as it is consumed in many countries, the top producers being Mexico, China, India and Japan. The present study aimed to evaluate the relation between Hg-induced oxidative stress and genotoxicity in diverse tissues of C. carpio. Specimens were exposed to 0.01 mg Hg/L (the maximum permissible limit for aquatic life protection), and lipid peroxidation, protein carbonyl content and the activity of antioxidant enzymes were evaluated at 96 h. Micronuclei frequency and DNA damage by comet assay were determined at 12, 24, 48, 72 and 96 h. Hg induced oxidative stress and genotoxicity on exposed fish, since inhibition of antioxidant enzymes activity and increases in lipid peroxidation, DNA damage and micronuclei frequency occurred. Blood, gill and liver were more susceptible to oxidative stress, while blood were more sensitive to genotoxicity. In conclusion, Hg at concentrations equal to the maximum permissible limit for aquatic life protection induced oxidative stress and genotoxicity on C. carpio, and these two effects prove to be correlated.