Objective:To investigate the protective effects of proanthocyanidin on radiation-induced injury of AHH-1 and HIEC cells,and to explore the possible molecular mechanism.Methods: CCK-8 assay was applied to examine the survival of AHH-1,HIEC cells after γ-ray irradiation with or without proanthocyanidin pretreatment.Annexin-Ⅴ/PI staining and flow cytometry analysis were used to evaluate the apoptosis and cell cycle of AHH-1 and HIEC cells.The expression of Bcl-2 protein was analyzed by Western blotting assay.Results: Pretreatment with proanthocyanidin significantly increased the cell survival rate after radiation(P<0.01).The apoptosis rates of cells in the proanthocyanidin+radiation group were (11.78% at 4 Gy\[AHH-1\] and 5.32% at 8 Gy\[HIEC\],respectively) greatly lower than those of the single radiation group (26.38% at 4 Gy\[AHH-1\] and 12.45% at 8 Gy\[HIEC\],respectively,P<0.01).Moreover,the inhibition of Bcl-2 protein expression in AHH-1,HIEC cells was attenuated in the proanthocyanidin+radiation group.Conclusion: Proanthocyanidin has satisfactory protective effect on radiation-induced cellular injury; the mechanism may be related to the attenuation of Bcl-2 protein inhibition.