间充质干细胞条件培养基激活Nrf2/ARE通路对抗H_2O_2致H9c2细胞的氧化应激损伤

目的:探讨间充质干细胞(MSC)条件培养基(MSCCM)对氧化应激损伤的心肌细胞的保护作用及机制。方法:用流式细胞术对MSC进行鉴定,再用MTT实验确定MSCCM对抗H2O2氧化应激损伤的最佳孵育时间。将H9c2细胞分为正常组、模型组、模型+MSCCM组和MSCCM组。模型+MSCCM组和MSCCM组均用MSCCM进行预孵育24 h,模型组和模型+MSCCM组用浓度为300μmol/L的H2O2作用4 h模拟心肌细胞的氧化应激损伤。利用流式细胞术检测损伤后心肌细胞的线粒体膜电位变化、凋亡比率等指标,通过荧光显微镜检测细胞ROS产生的变化,Western blot检测Nrf2/ARE通路的相关蛋白表达。结果:MSCCM组心肌细胞的线粒体膜电位、凋亡比率和ROS产生与正常组相比均无显著差异(P0.05);模型+MSCCM组的线粒体膜电位、凋亡比例和ROS产生与模型组相比差异显著(P0.01);在0 h到24 h这段时间内,心肌细胞Nrf2/ARE通路中的Nrf2核转位与HO-1表达均随着MSCCM孵育时间延长而增加。结论:MSCCM可以保护心肌细胞,对抗H2O2诱导的氧化应激损伤,其机制可能与激活Nrf2/ARE通路有关。

MSC-conditioned medium activates Nrf2/ARE pathway to protect H9c2 cells against oxidative stress

AIM: To investigate the protective effect of mesenchymal stem cell (MSC)-conditioned medium (MSCCM) on myocardial cell line H9c2 and its mechanism. METHODS: Verification of MSC was performed by flow cytometry analysis, followed by MTT assay to determine the optimal incubation time of MSCCM with myocardial cells. The cells were divided into 4 groups: normal (N) group, model (M) group, M+MSCCM group and MSCCM group. The cells in M+MSCCM group and MSCCM group were pre-incubated with MSCCM for 24 h. The cells in M group and M+MSCCM group were treated with 300 μmol/L H₂O₂ for 4 h to imitate oxidative injury of myocardial cells. Mitochondrial membrane potential and apoptotic rate of injured myocardial cells were detected by flow cytometry. The ROS production was measured by fluorescence microscopy. The nuclear translocation of Nrf2 and expression of HO-1 was examined by Western blot. RESULTS: No difference of mitochondrial membrane potential, apoptotic rate or ROS production between MSCCM group and N group was observed (P>0.05). The mitochondrial membrane potential depolarization, apoptotic rate and ROS production in M+MSCCM group were significantly lower than those in M group (P<0.01). The nuclear translocation of Nrf2 and expression of HO-1 in the myocardial cells were increased with MSCCM incubation time prolonged. CONCLUSION: MSCCM protects the myocardial cells against oxidative injury induced by H₂O₂. The anti-oxidative mechanism would be associated with the activation of Nrf2/ARE pathway.