摘要
目的探讨不同剂量^60Coγ射线对EJ细胞DNA损伤的情况，不同剂量^60Coγ射线照射EJ细胞后诱导磷酸化组蛋白H2AX焦点形成，以及与γH2AX表达量的关系。方法单细胞凝胶电泳检测DNA链断裂损伤情况。免疫荧光法检测不同剂量γ射线照射后立即、以及2Gyγ射线照射后不同时间的EJ细胞中γH2AX焦点的数量。流式细胞分析法检测不同剂量γ射线照射后EJ细胞中γH2AX蛋白表达量的变化。结果单细胞凝胶电泳结果显示，γ射线照射后DNA损伤情况明显加重，随照射剂量的增加，细胞尾矩不断加大，0 Gy组尾矩为0．24，4Gy照射组尾矩为5．26；免疫荧光结果显示，随着照射剂量的增加，γH2AX焦点数目及大小均明显增加，照射的剂量范围从0．1～4Gy均可检测，且照射剂量和焦点形成数目之间存在剂量-效应关系，0．1Gy照射组每个细胞中的焦点数平均达12．37个，4Gy照射组每个细胞中的焦点数平均达46个；2Gy7射线照射后24h仍可检测到γH2AX焦点，随时间延长焦点数目减少、强度减弱，具有时间依赖性。流式细胞检测结果表明，γ射线照射后γH2AX蛋白表达量明显增加，呈现明显量效关系，0．1和4Gy照射组γH2AX阳性细胞表达率分别为7．4％和29．2％。结论免疫荧光法检测照射后γH2AX焦点数目比其他实验方法更能敏感、直观的反映DNA损伤及修复情况，有望成为检测辐射损伤的理想生物指标。
Objective To investigate ^60 Coγ-rays induced DNA damage of human bladder cancer cell line EJ cells and the relationship between different doses of ^60 Coγ-rays, γH2AX foci number and γH2AX expression level. Methods EJ cells were exposed to different doses of ^60 Coγ-rays and the oliver tail moment （TM） of EJ ceils were analyzed with single cell gel electrophoresis （SCGE）. Immunofluorescent microscopy was used to analysis γH2AX foci formation in EJ cells after exposure to different doses of γ-ray irradiation and timecourse after exposure to 2 Gy γ-ray irradiation. FACSAria was used to detect the changes of γH2AX protein expression in EJ cells. Results The TMs of EJ cells were increased with the irradiation dose. The TM of 0 Gy group and 4 Gy group was 0.24 and 5.26, respectively. Inmmnofluorescent analysis demonstrated that yH2AX foci could be induced by y-ray irradiation in dose-dependent and time-dependent manners. The foci number and size in nuclei of EJ ceils was significantly increased after exposed to different doses of γ-ray irradiation and the foci remained detectable at 24 h after exposed to irradiation. The dose range in which foci could be clearly detected was from 0.1 to 4 Gy. FACSDiva showed that γH2AX protein expression was increased after exposure to different doses of γ-ray irradiation. γH2AX protein expression level of 0.1 Gy group and 4 Gy group was 7.4% and 29.2 %, respectively. Conclusions γH2AX foci could be the most sensitive indicator for DNA damage and repair in mammalian cells, and it might be a new biomarker for radiological emergency.
出处
《中华放射医学与防护杂志》
CAS
CSCD
北大核心
2009年第6期586-589,共4页
Chinese Journal of Radiological Medicine and Protection
