Adaptive protection of H_2O_2 preconditioning against dopamine-induced damage in PC12 cells

Aim To study the adaptive protection of H_2O_2 preconditioning against dopamine-induced damage in PC12 cells.Methods The apoptosis of PC12 cells was observed by electron microscope, PI stain flow cytometry (FCM) and Hoechst stain. The mitochondrial energy redox state was measured by MTT assay. The mitochondrial membrane potential(△Ψm) was investigated by the fluorescent probe of rhodamine 123.Results PC12 cells exposed to 50 μmol·L -1 DA showed chromatin condensation and nucleus fragmentation observed by electron microscope. Exposure to DA (50 μmol·L -1) for 24 h, the apoptosis of PC12 cells preconditioned by 10 μmol·L -1 H_2O_2 for 90 min as measured by Hoechst stain was significantly decreased,compared with no-preconditioned cells. Exposure to 50,100,and 200 μmol·L -1 H_2O_2 for 24 h, the proportion of apoptosis of PC12 cells was decreased from (20.9±1.8)%, (40.5±6.4)% and (88.1±3.9)% to (4.9±2.9)%, (12.0±1.4)%, (61.5±3.4)% after H_2O_2 preconditioning, respectively. By exposuring PC12 cells to 20,40,and 80 μmol·L -1 DA for 24 h, the rates of MTT metabolism were reduced and the effect was prevented by H_2O_2 preconditioning. After 50 μmol·L -1 DA exposure for 24 h,the mean fluorescence intensity of rhodamine 123 in no-preconditioned PC12 cells was decreased from (46.87±0.33) to (4.39±2.93),and that of preconditioned PC12 cells was decreased from (46.87±0.33) to (10.50±0.28). Conclusion H_2O_2 preconditioning possesses adaptive protection against dopamine-induced damage in PC12 cells.