Assessment of antioxidant defense system responses in the hepatopancreas of the freshwater crab Sinopotamon henanense exposed to lead

Lead (Pb) is a common pollutant in aquatic ecosystems, which produces a wide range of toxic biochemical effects in different organisms. The aim of the present study was to explore the mechanisms of acute toxicity and antioxidant defenses in freshwater crab Sinopotamon henanense induced by Pb. Hepatopancreas was collected from S. henanense exposed for 96 h to Pb (0, 9.188, 18.375, 36.75, 73.5, and 147 mg/l). Oxidative stress was examined using a suite of assays in crabs, including contents of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA), activities of antioxidative enzymes such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), and glutathione system-related parameters such as glutathione (GSH), glutathione S-transferase (GST), and glutathione reductase (GR). A dose-dependent increase of H₂O₂ and MDA was observed in the crabs after Pb exposure, while antioxidative enzymes activities were suppressed significantly (P < 0.05) at higher concentrations of Pb. The ratios of CAT/SOD, GPx/SOD, and GR/GPx were also suppressed. Our results suggested that acute exposure of Pb causes lipid peroxidation and harmful lessened antioxidant defenses of crabs. The above parameters were evaluated as potential biomarkers for Pb pollution monitoring and health assessment of crabs which is also important for the aquaculture of crabs.