Objective: To investigate the time order of autophagy and apoptosis in human U251 cells injury after H2O2 treatment.
Methods: 4 groups in this study were set up, normal control group, 1 mmol/L H2O2 (6 h,12 h, 24 h) group. The viability of U251 cells treated with H2O2 was measured by MTT assay. Cell apoptotic ratio was determined by flow cytometry analysis. Autophagic vacuoles were stained with monodansylcadaverine. The protein level of Beclin 1 and cytosolic cyt c were assayed by using Western blot.
Results: Compared with the control group, cell viability decreased significantly under 1 mmol/L H2O2 treatment in time-dependent way. Autophagic vacuoles and the expression of autophagic protein Beclin 1 increased at 6 h, but cell apoptotic ratio and cytosolic cyt c protein did not change obviously, cell apoptotic ratio and cytosolic cyt c protein level increased at 12 h and 24 h (P < 0.05).
Conclusion: Oxidative stress induced autophagy and apoptosis in U251 glioma cells, and autophagy eventuated ahead of apoptosis.