^(125)I籽源连续照射诱导人乳腺癌细胞凋亡的研究

Research on apoptosis of MCF-7 cells induced by continuous irradiation by ^(125)I seeds

目的探讨^(125)I籽源低剂量率γ射线持续照射诱导MCF7人乳腺癌细胞凋亡过程中Bcl2Bax的变化情况。方法用9粒表面放射活度为2775MBq的6711型^(125)I籽源连续照射MCF7细胞72h后,采用RTPCR和Westernblot法检测Bcl2和BaxmRNA和蛋白表达。常规细胞流式法和AnnexinV标记法直接检测MCF7细胞凋亡率。结果MCF7细胞经125I籽源照射后较对照组Bcl2mRNA的表达降低,BaxmRNA的表达升高;Westernblot检测Bcl2Bax比值,结果对照组为189±009,125I籽源照射组为062±008,两者差异有统计学意义(P<005)。常规细胞流式法检测照射组(n=10)和对照组(n=12)细胞凋亡率分别为(2361±727)%和(281±168)%,P<005。AnnexinV标记法检测两组细胞早期凋亡率分别为(2146±829)%和(194±138)%,P<005。结论125I籽源连续照射能够诱导Bcl2Bax比值的降低,促进MCF7细胞的凋亡。

Objective To detect the apoptotic rate and the changes of expressions of Bcl-2 and Bax in MCF-7 cells continuously irradiated with low dose rate γ-rays from ~ ~125 I seeds. Methods MCF-7 cells were exposed to the radiation for 72 hours from model 6711 ~ ~125 I seeds with an apparent activity of 27.75 MBq. Then, RT-PCR and Western blot were used to detect the expressions of Bcl-2 and Bax in MCF-7 cells. FCM and Annexin V assay were performed to detect the apoptotic rate of MCF-7 cells. Results Higher expression of Bcl-2 and lower expression of Bax in irradiated MCF-7 cells compared to those in the control cells were detected. FCM and Annexin V assay showed a significant increase of apoptotic rate in MCF-7 cells after continuous irradiation by ^(125)I seeds. Conclusion Continuous irradiation with ^(125)I increases the apoptotic rate of MCF-7 cells, and this increase may be induced by decreased ratio of Bcl-2/Bax.;