Effect of cadmium on SOD and CAT in hepatopancreas, antennary gland and gill of Procambarus clarkii.

The correlation between heavy metals pollution and crustacean's response is widely studied. The crayfish,Procambarus clarkii,has been extensively studied as a bioindicator of the effects of pollutants and also for its economic importance. This study aimed at evaluating the role of antioxidant defenses during cadmium-induced oxidative stress. The superoxide dismutases(SOD) and catalase(CAT) in hepatopancreas,antennary gland and gill of crayfish were investigated,which induced by cadmium at different concentrations and exposure times. Results showed:when crayfish were treated with 10 mg·L-1 Cd2+,the activities of SOD and CAT in hepatopancreas and antennary gland were first increased swiftly at earlier stage and then decreased to a stable lower level after 72 hours,while SOD and CAT activities in gill were not affected significantly(P0.05) . When crayfish were exposed to a higher concentration(30 mg·L-1) ,the activities of SOD and CAT in hepatopancreas,antennary gland and gill were inhibited significantly(P0.05) . In addition,SOD and CAT activities in gill were lower significantly than those in hepatopancreas and antennary gland(P0.05) ,the stress response to Cd2+ were more sensitive in hepatopancreas and antennary gland than in gill. These suggested that the antioxidant enzyme system in hepatopancreas and antennary gland played an important role on resisting Cd2+ at the earlier stage,while the activities of antioxidant enzyme were inhibited significantly at the later stage. In addition,the lower concentration of cadmium(7.5 mg·L-1) induced the activities of both SOD and CAT in hepatopancreas and antennary gland,while the higher concentration of cadmium(30 mg·L-1) inhibited significantly the activities of antioxidant enzyme in the three kind of tissues,this indicated that the antioxidase system might be damaged by the higher concentration of cadmium.