论文部分内容阅读
目的 研究X射线全身照射对小鼠骨髓细胞CyclinD、CDK4表达的影响 ,以探讨电离辐射诱导小鼠骨髓细胞G1 阻滞的分子机理。方法 采用Northernblot和半定量RT PCR方法分别检测CDK4、CyclinD基因转录水平变化 ;流式细胞仪检测了X射线全身照射小鼠骨髓细胞CyclinD、CDK4的表达及周期时程的变化。结果 2GyX射线全身照射后 12h骨髓细胞出现G1 期细胞百分数升高 (P <0 0 5 ) ,G2 +M期细胞百分数于照后 4h及 12h升高 (P <0 0 5 ) ;CyclinD基因转录水平从2h开始下降 ,48h达到最低 ,照后 72h恢复至正常水平 ,CDK4的变化趋势与CyclinD相似 ,只是从 8h开始下降 ,48h达到最低 ,照后 72h恢复假照组水平 ;CyclinD蛋白表达在照射后 2、4、2 4、48h显著降低 (P <0 0 1) ,CDK4蛋白表达在照射后 2h开始急剧下降 ,持续至照射后 48h仍未恢复到对照水平 (P <0 0 1)。结论 2GyX射线全身照射可诱导小鼠骨髓细胞发生G1 、G2 阻滞 ;CyclinD、CDK4基因及其蛋白产物可能在电离辐射诱导的小鼠骨髓细胞周期阻滞中起重要作用。
Objective To study the effects of X-ray irradiation on the expression of CyclinD and CDK4 in bone marrow cells of mice and explore the molecular mechanism of G1 arrest in mouse bone marrow cells induced by ionizing radiation. Methods The changes of CDK4 and CyclinD gene transcription were detected by Northern blot and semi-quantitative RT-PCR. The expression of CyclinD and CDK4 in bone marrow cells were detected by flow cytometry. Results The percentage of cells in G1 phase increased (P <0.05), the percentage of cells in G2 + M phase increased at 4h and 12h (P <0.05), the level of CyclinD gene transcripts The expression of CyclinD protein was up-regulated from 2h to the lowest at 48h and returned to the normal level at 72h after irradiation. The trend of CDK4 was similar to that of CyclinD, but decreased from 8h to 48h, 2,4,2,48h (P <0.01). The expression of CDK4 protein decreased sharply at 2h after irradiation, and remained unchanged to the control level 48h after irradiation (P <0.01). Conclusion 2Gy X-ray can induce G1 and G2 arrest in mouse bone marrow cells. CyclinD, CDK4 gene and their protein products may play an important role in ionizing radiation-induced mouse bone marrow cell cycle arrest.