摘要
目的比较G1期检测点和G2期检测点两种检测点的放射敏感性及细胞凋亡发生规律。方法野生型p53功能正常的人类急性淋巴细胞性白血病(MOLT4)细胞株在体外对数生长期给予不同剂量(2、5、10、20GY)的X射线照射后,继续培养0、3、6、9h,随后分成两组:一组细胞收获并固定,用Cyclins/DNA流式细胞术对CyclinE,CyclinA和CyclinB1分别进行标记,Cellquest软件分析;另一组同步采用膜联蛋白V/碘化丙锭(API技术)和AnnexinV/PI技术分析细胞凋亡。结果小剂量X射线(2、5GY)照射后,MOLT4细胞G2期检测点被激活,表现为:照射后3～9h,G2期Cyclins(CyclinA和CyclinB1)迅速升高并累积于G2期,G1期Cyclins(CyclinE)含量逐渐减少;9h时G2期细胞出现明显凋亡(凋亡率为9.5%)。大剂量X射线(10、20GY)照射后,细胞G1期检测点被激活,表现为:照射后3～9h,G1期Cyclins(CyclinE)持续性升高并累积于G1期,G2期Cyclins(CyclinA和CyclinB1)含量下降;且3h时G1期细胞便出现明显凋亡(凋亡率为10.28%)。结论不同剂量X射线可激活不同的细胞周期检测点,并诱导相应周期时相内的细胞凋亡,细胞凋亡率的高低及诱导速度呈现剂量依赖性。
Objective To analyze the influence on cell cycle checkpoints and apoptosis induced by different dosage of X-ray.[WT5”HZ]Methods MOLT-4 cells (wide-type p53) after being irradiated by different dosage of X-ray (2,5,10,20 Gy) were gathered at 0,3,6,9 h,then divided into two groups:in one group,cells were fixed and Cyclin E,A,and B1 expression was detected by cyclins/DNA flow cytometry;in the other group,cell apoptosis was detected by API and Annexin/PI assay.Results After MOLT-4 cells were irradiated by low dosage of X-ray (2,5 Gy),the content of G_1 cyclins (cyclin E) was decreased,but G_2 cyclins (Cyclin A,B1) increased quickly and accumulated distinctly in G_2 phase,indicating that G_2 checkpoint was activated.Simultaneously,apoptotic rate of MOLT-4 cells was increased slowly (reached 9.5% at 9th h) and cell cycle specific apoptosis happened in G_2 phase.However,after being irradiated by high dosage of X-ray(10,20 Gy),the content of G_1 cyclin (cyclin E) was increased quickly and accumulated distinctly in G_1/S phase,while G_2 cyclins (Cyclin A,B1) decreased gradually,indicating that G_1 checkpoint was activated.Synchronously,apoptotic rate was increased quickly (reached 15.06% at 3rd h) and cell cycle specific apoptosis happened in G_1 phase.Conclusion Different doses of X-ray can activate different cell cycle checkpoints and then induce apoptosis in the same cell cycle specific phase.Apoptotic rate and the inducing time are related to the dosage of X-ray in a dosage-dependent manner.
出处
《中华实验外科杂志》
CAS
CSCD
北大核心
2005年第7期798-800,共3页
Chinese Journal of Experimental Surgery
基金
国家自然科学基金资助项目(39730270
39670365)
国家杰出青年基金资助项目(39725027)
国家973肿瘤计划(G1998051212)
卫生部临床重点学科资助项目(20012537)
