【摘要】 目的研究热休克蛋白70(HSP70)在紫外线C致DNA损伤中的保护作用。方法用254 nm紫外线不同照射剂量(10,20,40,80 J/m2)照射槲皮素(quercetin)抑制HSP70表达的A549细胞株(A549/quercetin),用Western-blot检测HSP70的水平,用碱性单细胞凝胶电泳检测DNA损伤,用彗星细胞率和Olive尾矩评价DNA损伤情况。A549细胞作为正常对照组,DMSO处理作为溶剂对照组(A549/DMSO)。结果无论在A549组、A549/DMSO组,还是在A549/quercetin组,DNA损伤的彗星细胞率随着紫外照射的剂量增加而逐渐增加,在10 J/m2时,未观察到HSP70的保护作用,3组的彗星细胞率差异无统计学意义;在20 J/m2照射时,可以观察到HSP70的保护作用,但不明显;40 J/m2照射时,观察到HSP70对DNA有很明显的保护作用;80 J/m2照射时,HSP70的保护作用又逐渐地消失了。进一步分析40 J/m2照射的Olive尾矩显示,与A549组或A549/DMSO组相比,A549/quercetin组Olive尾矩明显增加,差异有统计学意义(P<0.01)。结论HSP70能保护细胞免受一定剂量范围内的紫外线C照射引起的DNA损伤。更多还原

【Abstract】 Objective To study the protective role of HSP70 against DNA damage caused by ultraviolet C.Methods A549 cells inhibited by quercetin were irradiated by different ultraviolet C(0,10,20,40,80 J/m2),A549 cells as normal control and A549 cells treated by DMSO(≤1‰)as a solvent control.HSP70 expression was detected using western-blot assay.DNA damage was detected by single cell gel electrophoresis(SCGE).Results The results showed that the levels of DNA damage in A549 cells of both normal and inhibited HSP70 increased after exposed to an incident dose of 0,10,20,40,and 80 J/m2.The protection against UVC-induced DNA damage in cells with normal HSP70 was observed at UVC dose 20 J/m2 and maximized at 40 J/m2,but this protection gradually disappeared up to 80 J/m2 compared with cells with inhibited HSP70.Conclusions The results suggest that HSP70 may play a role in protecting A549 cells from DNA damage caused by UVC irradiation and that there is a threshold of protection of HSP70 from DNA damage at UVC irradiation.更多还原