[Effects of Cd2+ on glutathione system of hepatopancreas and gills in freshwater crab Sinopotamon yangtsekiense].

Laboratory experiment was carried out to determine the oxidative status in freshwater crab Sinopotamon yangtsekiense exposed to Cd2+ (7.25, 14.5, 29, 58 and 116 mg/L) for different treating times (24, 48, 72 and 96 h). The indexes were measured in the hepatopancreas and gills of the crab, which include the levels of reduced glutathione (GSH) and oxidized glutathione (GSSG), the activities of glutathione peroxidase (GPx), glutathione S-transferase (GST) and glutathione reductase (GR), as well as the ratio of GSH/GSSG. In the hepatopancreas, there was a gradual decrease in the level of GSH and it was (28.805 +/- 2.239) mg/g at 116 mg/L for 96 h while there was an initial elevation and later decrease in the activity of GPx which associated with no significant differences in the level of GSSG and the activities of GST and GR compared with controls. In the gills, with the increase of concentration of Cd2 and duration in treatment, the level of GSH was decreased gradually while there was no pronounced change of the level of GSSG. The activity of GPx was enhanced notably and then was reduced, and the activities of GST and GR were decreased by 44% and 79% after exposed to Cd2 for 96 h. There were evident reduction in the ratio of GSH/GSSG in both hepatopancreas and gills. The results demonstrated that the changes in the studied indicators of oxidative stress (GSH, GSSG, GPx, GST, GR and GSH/GSSG ratio) may sensibly reflect the oxidative stress to aquatic animal induced by Cd2+ and the GSH/GSSG ratio could be considered as a biological monitoring index of the pollution induced by Cd2+ in aquatic ecosystems.