活性氧在异烟肼诱导L-02细胞DNA损伤中的作用及槲皮素的保护效应

目的：探讨活性氧（ROS）在异烟肼（INH）诱导的L-02细胞DNA损伤中的作用及槲皮素的保护效应。方法：将L-02细胞分为空白对照组、INH组（10 mmol/L INH）；槲皮素低剂量组（10 mmol/L INH+25 μmol/L槲皮素）；槲皮素高剂量组（10 mmol/L INH+50 μmol/L槲皮素）。细胞处理24 h后，采用彗星试验检测细胞DNA损伤情况；分别应用荧光探针DCFH-DA和Rhodamine123检测细胞ROS水平及线粒体膜电位。结果：与空白对照组比较，L-02细胞经INH和槲皮素处理后，INH组细胞尾部DNA百分含量、尾长和尾矩均显著增加（P<0.01）；与INH组相比，低和高剂量槲皮素组细胞的尾部DNA百分含量、尾长和尾矩均明显减少（P<0.05或P<0.01）。INH组细胞线粒体ROS水平比空白对照组显著升高（P<0.01）；而低和高剂量槲皮素组细胞线粒体ROS水平比INH组明显降低（P<0.05或P<0.01）。INH组细胞线粒体膜电位显著低于空白对照组（P<0.01），而低和高剂量槲皮素组细胞线粒体膜电位明显高于INH组（P<0.05或P<0.01）。结论：INH能诱导L-02细胞DNA损伤，ROS介导的线粒体损伤在INH诱导L-02细胞DNA损伤的过程中发挥了重要作用；槲皮素对INH诱导L-02细胞DNA损伤具有保护效应，可能与其抑制ROS介导的线粒体损伤有关。

The role of reactive oxygen species in isoniazid-induced DNA damage in L-02 cells and the protective effect of quercetin

OBJECTIVE: To investigate the role of reactive oxygen species (ROS) in isoniazid (INH)-induced DNA damage in L-02 cells and the protection by quercetin. METHODS: L-02 cells were divided into several groups:blank control,INH (10 mmol/L),quercetin low dose (10 mmol/L INH +25 μmol/L quercetin) and high dose (10 mmol/L INH +50 μmol/L quercetin). After cells were treated for 24 hours,DNA damage was detected by using the Comet test;ROS generation and mitochondrial membrane potential were evaluated by application of fluorescent probes DCFH-DA and Rhodamine123. RESULTS: Compared with the blank control group,the percentages of tail DNA,tail length and tail moment (from the Comet assay) of the INH group were significantly increased (P<0.01). Compared with the INH group,the percentages of tail DNA,tail length and tail moment of the low and high dose quercetin groups were significantly reduced (P<0.05 and P<0.01,respectively). The levels of mitochondrial ROS in cells of the INH group were significantly increased over the blank control group (P<0.01);the levels of mitochondrial ROS in the low and high dose quercetin groups were significantly decreased than that of the INH group (P<0.05 and P<0.01,respectively). The mitochondrial membrane potential of the INH group was significantly lower than that of the blank control group (P<0.01). The mitochondrial membrane potential of the low and high dose quercetin groups were significantly higher than that of the INH group (P<0.05 and P<0.01,respectively). CONCLUSION: INH can induce DNA damage in the L-02 cells and the damage may involve ROS-mediated mitochondrial damage. Quercetin has a protective effect against the INH-induction of DNA damage and the effect may be related to its inhibition of ROS-mediated mitochondrial damage.