Objective        To determine the protective effect of proanthocyanidins on oxidative damage and cell cycle arresting in PC12 cells induced by hydrogen peroxide

and to investigate the role of cell cycle regulatory genes cellular-Abelson gene (c-Abl) and polo-like kinase-1 (plk1) in the protection.         Methods        PC12 cells were incubated with different concentrations of proanthocyanidins and induced by 100  μmol/L hydrogen peroxide for 6 h

and then the cell viability was measured by MTT assay

and the distribution of cell cycle was measured by flow cytometry

and the protein expression of c-Abl and plk1 was detected by Western blotting.         Results        Compared with the PC12 cells in control group

hydrogen peroxide significantly decreased cell viability and increased S phase distribution in PC12 cells (P0.01)

and the protein expression level of c-Abl and plk1 gene in PC12 cells was also increased significantly by hydrogen peroxide (P0.01); Compared with the group of PC12 cells induced by hydrogen peroxide

proanthocyanidins significantly increased cell viability of PC12 cells in the range of experimental doses (P0.01). Proanthocyanidins relieved the S phase arrest induced by hydrogen peroxide (P0.01)

and the protein levels of c-Abl and plk1 in PC12 cells was also decreased by proanthocyanidins in a dose- dependent manner (P0.01).          Conclusion        Proanthocyanidins can protect PC12 cells from the cytotoxic stresses induced by hydrogen peroxide

and the protective mechanism may be mediated by relieving the S phase arrest and decreasing the protein expressional level of c-Abl and plk1 gene.