Protective effects of protopine on hydrogen peroxide-induced oxidative injury of PC12 cells via Ca2+ antagonism and antioxidant mechanisms

Calcium and lipid peroxidation play important roles in oxidative stress-induced cellular injury and apoptosis, which ultimately cause cell death. In this study we examined whether protopine had a neuroprotection against H2O2-induced injury in PC12 cells. Pretreatment of PC12 cells with protopine improved the cell viability, enhanced activities of superoxide dismutase, glutathione peroxidase and catalase, and decreased malondialdehyde level in the H2O2 injured cells. Protopine also reversed the increased intracellular Ca2+ concentration and the reduced mitochondrial membrane potential caused by H2O2 in the cells. Furthermore, protopine was able to inhibit caspase-3 expression and cell apoptosis induced by H2O2. In summary, this study demonstrates that protopine is able to relieve H2O2-induced oxidative stress and apoptosis in PC12 cells, at least in part, by Ca2+ antagonism and antioxidant mechanisms.