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目的探索氢醌对人支气管上皮细胞遗传毒性的分子机制,并研究X线修复交叉互补基因1(XRCC1)对氢醌致人支气管上皮细胞DNA损伤是否有保护作用。方法通过RNA干扰敲除XRCC1基因,通过转染重组质粒pEGFP-C1-pU6-dsRNA建立XRCC1缺陷细胞;正常人支气管上皮细胞和转染空载体pEGFP-C1的细胞分别作为正常对照组和载体对照组;3种细胞用不同浓度(10 ～100 μmol.L-1)的氢醌作用4 h,分别进行MTT实验和彗星实验来检测氢醌的毒性。结果 MTT结果显示,不同浓度(10 ～100μmol.L-1)氢醌作用的XRCC1缺陷细胞,490 nm波长处吸光度值低于对照组细胞,提示缺陷细胞的细胞存活率比正常细胞低;彗星实验结果显示,不同浓度的氢醌对XRCC1缺陷细胞DNA损伤比对照组细胞更严重,而2个对照组细胞之间没有明显差异。结论 XRCC1基因在氢醌导致的细胞损伤的修复方面起着重要的作用。
Objective To explore the molecular mechanism of hydroquinone genotoxicity on human bronchial epithelial cells and to investigate whether XRCC1 can protect against DNA damage induced by hydroquinone in human bronchial epithelial cells. Methods XRCC1 gene was knocked down by RNA interference and XRCC1-deficient cells were constructed by transfecting the recombinant plasmid pEGFP-C1-pU6-dsRNA. Normal human bronchial epithelial cells and cells transfected with empty vector pEGFP-C1 were used as normal control group and vehicle control group ; 3 kinds of cells with different concentrations (10 ~ 100 μmol.L-1) of hydroquinone for 4 h, respectively MTT test and comet assay to detect the hydroquinone toxicity. Results The results of MTT assay showed that the XRCC1-deficient cells treated with 10-100 μmol·L-1 hydroquinone had lower absorbance at 490 nm than that of the control cells, suggesting that the cell viability of defective cells was lower than that of normal cells. The comet assay The results showed that different concentrations of hydroquinone had more severe DNA damage in XRCC1-deficient cells than that in control cells, but there was no significant difference between the two control cells. Conclusion The XRCC1 gene plays an important role in the repair of hydroquinone induced cell injury.