高剂量X射线对人离体外周血中有核细胞DNA的损伤及其修复

The DNA Damage and Repair of High Doses of X-Ray on Human Peripheral Blood Nucreated Cells

目的:应用单细胞凝胶电泳技术检测X射线对离体外周血中有核细胞的DNA的损伤及损伤修复。方法:采用血常规正常的离体人外周血,用能量为6MV的X射线给予0Gy、2Gy、4Gy、6Gy、8Gy、10Gy的剂量照射,分别在0.5h、1h、2h用单细胞凝胶电泳技术检测全血中有核细胞的彗星率、慧尾长度和尾部DNA含量。结果:0Gy的假照组彗星率1%,2Gy时彗星率到达27.10%,4Gy时彗星率达到76.32%,6Gy、8Gy、10Gy时彗星率在90%以上,接近100%。2Gy、4Gy时经2h修复彗星率下降有统计学意义(P<0.05);6Gy、8Gy、10G时彗星率下降无统计学意义(P<0.05)。DNA修复在1h内最快,在1h～2h间修复较1h内减慢。结论:在2Gy以上的X射线照射下全血中有核细胞的DNA均受到不同程度的损伤。6Gy以上DNA损伤接近100%,且修复明显减慢或消失,推测:6Gy的X射线可能是全血细胞所能承受的极限。

Objective To investigate the damage and repair of high doses of X-ray on human peripheral blood nucleated cells DNA by Single Cell Gel Electrophoresis（SCGE）.Methods Using human peripheral blood with normal blood routine,give the dose of 0Gy,2Gy,4Gy,6Gy,8Gy,10Gy X-ray radiation with energy of 6MU.Detect the percentage of comet-like tail,tail length and content of DNA in tail of whole blood cell＇s DNA by SCGE technique in 0.5h,1h,2h.Results The comet rate is 1% in 0Gy group,27.10% in 2Gy group,76.32% in 4Gy group,above 90%,nearly 100% in 6Gy,8Gy,10Gy.The comet rate has reduced experience 2h repair in 2Gy,4Gy,have statistical significance,the comet rate has no significantly reduce in 6Gy,8Gy,10Gy,have no statistical significance.DNA repair fast in 1h,slower in 1h-2h.Conclusion The DNA of whole blood cell would damage by above 2Gy X-ray.Nearly 100% damaged would happen over 6Gy X-ray,with repairing decreased even disappeared.It＇s suggested that 6Gy is possibly the maximum dose the human whole blood cell can withstand.