X射线对小鼠脾细胞内P16、cyclin D1和CDK4表达的影响

目的:探讨X射线对小鼠脾细胞内P16、cyclin D1和CDK4表达的影响.方法:采用细胞间接荧光标记法、FACScan流式细胞仪检测不同剂量X射线全身照射后小鼠脾细胞内P16、cyclin D1和CDK4三种蛋白表达的时程变化和量效关系.结果:2.0 Gy X射线照后24 h小鼠脾细胞P16表达明显高于假照组;CDK4表达水平在照后8 h明显降低,持续至照后72 h仍低于正常水平.周期蛋白cyclin D1表达轻度下调.不同剂量照射后P16蛋白表达呈剂量依赖性增加,1.0～4.0 Gy组与假照射组相比显著增多(P＜0.05,P＜0.01);cyclin D1蛋白表达随剂量升高有降低趋势;CDK4亦呈剂量依赖性降低,0.5～6.0 Gy组与假照组比较差异具有显著性(P＜0.05,P＜0.01).结论:P16/cyclin D1/CDK4/pRb通路在电离辐射诱导脾细胞G1期阻滞中可能起十分重要作用.

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 ( P<0.05, 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 ( P<0.05, 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.