中文摘要：

目的：观察^60 Coγ射线照射对血管内皮细胞生物学作用的影响。方法用不同剂量^60 Coγ射线照射人脐静脉血管内皮细胞（ HUVEC），通过细胞生长曲线和克隆形成实验观察细胞增殖存活情况；流式细胞术检测照射后细胞周期的变化；中性单细胞凝胶电泳及蛋白印迹法（ Western blot ）观察细胞照射后DNA分子损伤及修复情况。结果^60 Coγ射线照射后， HUVEC细胞生长速度及增殖率降低，降低程度与照射剂量呈正相关；HUVEC细胞周期出现G2／M期阻滞；HUVEC细胞出现明显的DNA双链断裂，γH2AX和DNA－PKcs表达增加。结论^60 Coγ射线照射抑制血管内皮细胞增殖，导致G2／M期阻滞，促进DNA断裂，相关修复蛋白表达增加。

英文摘要：

Objective To determine the effect of ^60 Coγ-ray irradiation on biological behaviors in cultured vascular endothelial cells in vitro.Methods Human umbilical vein endothelial cells （ HUVECs） were exposed to ^60 Coγ-ray irradiation at different doses .After irradiation , the proliferation of HUVECs was evaluated by cell growth curve and colony formation assay .Cell cycle was detected by flow cytometry.DNA damage and repair were analyzed by neutral single-cell gel electrophoresis , and the expression of related proteins was detected by Western blotting .Results After γ-ray irradiation , the proliferation of HUVECs was significantly inhibited in a dose-dependent manner.The cells were arrested at G 2/M stage after irradiation exposure .Obvious DNA double-strand breaks and enhanced expression of γH2AX and DNA-PKcs were observed in the HUVECs after irradiation .Conclusion ^60 Co γ-ray irradiation inhibits the proliferation of HUVECs, induces the cells arrested at G 2/M stage, promotes DNA break, and enhances the expression of repair-related proteins in endothelial cells .