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本研究探讨了顺铂对人体胃腺癌M_(85)细胞放射敏感性的影响。实验证实顺铂对有氧M_(85)细胞有放射增敏作用,增敏比为1.19。用中性滤膜洗脱方法检测了顺铂对辐射所致的DNA双链断裂(dsb)及其修复的影响。低浓度(1μg/ml)顺铂引起的DNA交联对洗脱率无显著影响。未经顺铂处理的细胞,DNA dsb修复动力学表现为双相,即快、慢修复相,快修复相在10min内完成,半修复时间为5min;但经顺铂处理的细胞,其DNA dsb修复能力受到明显损害。结果提示,细胞DNA dsb修复抑制可能是顺铂放射增敏作用的分子机制。
This study investigated the effect of cisplatin on radiosensitivity of gastric adenocarcinoma M_(85) cells. Experiments confirmed that cisplatin had radiosensitization on aerobic M_(85) cells with a sensitization ratio of 1.19. The effects of cisplatin on DNA double-stranded breaks (dsb) and their repair were examined using a neutral filter elution method. DNA cross-linking caused by low concentrations (1 μg/ml) of cisplatin had no significant effect on the elution rate. In cells not treated with cisplatin, the kinetics of DNA dsb repair was biphasic, ie, fast and slow repair phases. The fast repair phase was completed within 10 minutes, and the half-repair time was 5 minutes; however, DNA dsb was treated with cisplatin-treated cells. Repair capacity has been significantly damaged. The results suggest that the inhibition of DNA dsb repair may be the molecular mechanism of cisplatin radiosensitization.