Changes of superoxide dismutase and catalase activities in crucian carp (Carassius auratus) exposed to copper and recovery response

In this study, the effects of antioxidant enzyme parameters in the freshwater fish Carassius auratus to water-borne copper (Cu2+) exposure were assessed, and the reversibility of enzyme activities post-copper exposure were studied. The fish were exposed to different concentrations (0.05, 0.1, 0.2, 0.5 and 1.0 mg/L) of copper for 96 h, and then the 1.0 mg/L exposure group was transferred to the clean water (control water without the introduced copper) and exampled after 1, 5, 10, 15, and 30d to assess the recovery profile. Responses of the activities of superoxide dismutase (SOD) and catalase (CAT) in kidney, gill, spleen and brain to copper exposure and the recovery profile were investigated. As shown in the results, the changes of the two antioxidant enzymes activities in different organs of C. auratus exposed to copper are different, SOD and CAT activities in gill and spleen increased at low copper concentrations and decreased at high copper concentrations. SOD and CAT activities in brain all decreased at various copper concentrations, while SOD activity in kiney increased at all copper concentrations. After removing 1.0 mg/L copper exposure, all the antioxidant enzyme activities recovered to the normal levels within 30 days, and SOD and CAT activities in gill normalized in the fastest speed, while the both enzyme activities in kindey normalized in the slowest speed. SOD and CAT activities in brain of C. auratus are more sensitive to copper exposure, which can be used as sensitive biomarkers to assess copper contamination in aquatic ecology.