活性氧清除剂保护心肌细胞对抗化学性缺氧损伤

摘要

目的 探讨活性氧(ROS)清除剂N-乙酰半胱氨酸(NAC)能否保护H9c2心肌细胞对抗化学性缺氧引起的损伤.方法 应用化学性低氧模拟物氯化钴(CoCl_2)处理H9c2心肌细胞,建立化学性缺氧损伤心肌细胞的实验模型.在CoCl_2处理H9c2心肌细胞前60min把NAC加入培养基中,作为预处理.应用CCK-8比色法检测细胞存活率;双氯荧光素(DCFH-DA)染色荧光显微镜照相检测细胞内ROS水平;罗丹明123(Rh123)染色荧光显微镜照相检测线粒体膜电位(MMP);谷胱甘肽试剂盒检测GSSG/(GSSG+GSH)的比值.结果 600 μmol/L CoCl_2明显地降低细胞存活率.在CoCl_2处理H9c2心肌细胞前60 min,应用500～2000μmol/L NAC能剂量依赖性地抑制CoCl_2对心肌细胞的损伤作用,使细胞存活率显著升高.2000/μmol/LNAC能明显地对抗CoCl_2引起的氧化应激反应,使H9c2心肌细胞内GSSG/(GSSG+GSH)的比值及ROS水平明显降低,并明显地对抗CoCl_2对MMP的抑制作用.结论 NAC能显著地对抗化学性缺氧诱导的心肌细胞损伤,此心肌细胞保护作用与其降低GSSG/(GSSG+GSH)的比值及ROS水平,改善MMP等机制有关.%Objective To investigate the protective effect of reactive oxygen species (ROS) scavenger, N-acetyl-L-cysteine (NAC), against H9c2 cardiomyocytes from injuries induced by chemical hypoxia. Methods H9c2 cells were treated with cobalt chloride (CoCl_2), a chemical hypoxia-mimetic agent, to establish the chemical hypoxia-induced cardiomyocyte injury model. NAC was added into the cell medium 60 min prior to CoCl_2 exposure. The cell viability was evaluated using cell counter kit (CCK-8), and the intercellular ROS level was measured by 2', 7'- dichlorfluorescein-diacetate (DCFH-DA) staining and photofluorography. Mitochondrial membrane potential (MMP) of the cells was observed by Rhodamine 123 (Rh123) staining and photofluorography, and the ratio of GSSG/ (GSSG+GSH) was calculated according to detection results of the GSSG kit.Results Exposure of H9c2 cardiomyocytes to 600 μmol/L CoCl_2 for 36 h resulted in significantly reduced cell viability. Pretreatment with NAC at the concentrations ranging from 500 to 2000 μmol/L 60 min before CoCl_2 exposure dose-dependently inhibited CoCl_2-induced H9c2 cell injuries, and obviously increased the cell viability. NAC at 2000 μmol/L obviously inhibited the oxidative stress induced by CoCl_2, decreased the ratio of GSSG/(GSSG+GSH), increased ROS level, and antagonized CoCl_2-induced inhibition on MMP. Conclusions NAC offers obvious protective effect on H9c2 cardiomyocytes against injuries induced by chemical hypoxia by decreasing in the ratio of GSSG/ (GSSG+GSH) and ROS level and ameliorating MMP.