Effect of ionizing radiation on expression of P16 cyclin D1 and CDK4 in splenocyctes in mice

Objective: To determine and analyze the changes in expression in different doses and different time intervals of P16? cyclin D1 and CDK4, respectively, in splenocytes in mice after whole body irradiation. Methods: Indirect fluorescence labble technique and flow cytometry (FCM) was used in the examing. Results: The results showed that protein P16 of splenocytes elevated significantly at 24 h after 2.0 Gy X irradiation in compared with that of sham irradiation. CDK4 protein expression was dramatically decreased at 8 h lasted to 72 h, after 2.0 Gy X rays. cyclinD1 protein showed a little reduction after 2.0 Gy X irradiation. Overexpression of P16 depended on the doses of radiation. The expressions of P16 in 1.0~4.0 Gy group were significantly increased in comparison with that in sham irradiated group ( P0.05, P 0.01 ). cyclin D1 expression showed declining tendency after different doses X irradiation. The reduction of CDK4 expression was significant in 0.5~6.0 Gy group ( P0.05, P 0.01), and CDK4 was decreasing with X rays doses increasing. Conclusion:These results suggeste that P16/cyclin D1/CDK4/pRb pathway may play an important role in G 1 arrest of splenocytes induced by ionizing radiation.