中文摘要：

目的探讨核苷酸切除修复交叉互补基因2（excision repair crosscomplementation group2／Xeroderma pigmentosumD，ERCC2／XPD）在短波紫外线（UVC）所致细胞DNA损伤与修复过程中的作用。方法采用中国仓鼠卵巢细胞系（CHO）野生型AA8及ERCC2蛋白表达缺失型UV5构建细胞对照模型。MTT法比较两种细胞经UVC处理后细胞抑制率的差别；彗星试验与Rad51免疫荧光试验检测经不同照射强度的UVC处理后修复1、3、6和24h，不同细胞对UVC所致DNA损伤修复能力的差异。结果与野生型AA8相比，UV5对UVC所致DNA损伤更加敏感，细胞存活率降低（P〈0．05）。彗星试验和Rad51免疫荧光试验结果显示，UV5细胞DNA损伤程度较AA8严重，并且修复UVC所致DNA损伤的能力降低（P〈0．05）。结论ERCC2／XPD基因缺失细胞DNA损伤修复能力下降，说明ERCC2／XPD修复酶在UVC所致DNA损伤的切除修复过程中发挥重要作用。

英文摘要：

Objective To explore the function of ERCC2/XPD in the repair of DNA damage induced by UVC. Methods Chinese hamster ovary （CHO） cell line including AA8 （wild-type） and UV5 （mutant type, ERCC2/XPD defective）, was selected as a cell control model. The cell inhibition rate of AA8 and UV5 after UVC treatment was estimated by MTT assay, and DNA repair capacity to difference irradiation intensity of UVC in cells after 1 h, 3 h, 6 h, 24 h incubation were measured by the Comet Assay and Rad51 immunofluorescenee test. Results As compared to AAS, UV5 was more sensitive to UVC, and whose cell viability decreased. Comet assay and RadS1 immunofluorescence test results show, DNA damage level of UV5 was more serious than AA8. In addition, the DNA damage repair capacity reduced obviously compared with AA8. Conclusion DNA damage repair capacity of UV5 cells reduced due to ERCC2/XPD defective, indicating us that ERCC2/XPD play a critical role in the repair process of DNA damage induced by UVC.