The Effect of X-ray Irradiation on Proliferation of in Vitro Cultured Astrocytes and the Mechanism

Objective:To investigate the effect of X-ray on proliferation of cultured astrocytes(AS) and the action mechanism.Methods: The 80% confluent cultured AS were irradiated by different doses of X-ray,and effects of irradiation on cell cycle and apoptosis were analyzed by flow cytometry.The 80% confluent cultured AS were synchronized by serum deprivation for 48 h,then the cultured AS were randomly divided into 2 groups: control group(10% FBS) and irradiation group(10% FBS+irradiation).Western bolt was used to detect the expression of PCNA,p53 and cyclin E.Results:X-ray irradiation could reduce the percentage of cells in S phase in a dose-dependent manner,but not increase the apoptosis rate of AS.After the culture was serum-starved for 24 h,almost confluent AS remained at G0 phase.As a response to FBS,the percent of S phase cells and the expression levels of PCNA and cyclin E were increased in control group;In irradiation group,the percent of S phase cells was decreased dose-dependently.The expression of PCNA and cyclin E was also inhibited significantly,and the expression of p53 increased significantly in irradiation group as compared with control group.Conclusion: X-ray can effectively inhibit proliferation of AS by regulating cell cycle of AS.