HSP70过表达对紫外线C致DNA损伤的影响

[目的]研究HSP70过表达对紫外线致DNA损伤的影响.[方法]设A549、A549/pcDNA、A549/HSP70 3个组,分别用不同紫外线照射剂量(0、10、20、40、80 J/m2)照射HSP70表达正常和过表达的A549细胞株,用Western-blot检测HSP70的水平,用碱性单细胞凝胶电泳检测DNA损伤情况.[结果]DNA损伤的彗星率随紫外线照射的剂量增加而逐渐加重.当在相同剂量40J/m2时,A549/HSP70组的彗星率为24 %、尾矩为14.31±1.60,A549相应为40 %、18.83±0.41,A549/pcDNA为40%、18.67±0.81.在40 J/m2照射所致的Olive尾矩明显减少,与对照组比较差异有显著性(P＜0.01).[结论]HSP70能保护细胞免受一定剂量范围内的紫外线引起的DNA损伤.

Overexpression HSP70 Protects A549 Cells Against DNA Damage Caused by Ultraviolet C Irradiation

[Objective] To study the protective role of HSP70 against DNA damage caused by ultraviolet C. [Methods] A549 cells transfected by HSP70 gene were irradiated by different strength of Ultraviolet C(0, 10, 20, 40, 80 J/m2), with A549 cells as normal control and A549 cells trasfected by pcDNA3.0 vector as a blank control. HSP70 expression was detected using western-blot assay. DNA damage was detected using single cell gel electrophoresis(SCGE). [Results] The results showed that the levels of DNA damage increased with the increasing strength of Ultraviolet C in A549 and transfected A549 cells. The protection against UVC-induced DNA damage in cells with overexpressed HSP70 was observed at UVC dose 20J/m2 and 40J/m2. Compared with A549 cells, the values of the Olive tail moment in cells with overexpressed HSP70 decreased significantly(P < 0.01). [Conclusion] These results suggested that overexpressed 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 by UVC irradiation.