视神经萎缩症蛋白1通过抑制氧化应激减少高糖高脂诱导的心肌细胞凋亡

OPA1 ameliorates cardiomyocyte apoptosis induced by high fat and high glucose via inhibiting oxidative stress

目的研究高糖高脂对心肌细胞的影响及视神经萎缩症蛋白1(optical atrophy-1,OPA1)在其中的具体作用。方法将高糖培养基培养的小鼠心肌细胞分为3组:高糖+0、200、400μmol/L软脂酸钠组,并分别干预8 h和16 h。采用si RNA敲低心肌OPA1表达,进一步将400μmol/L软脂酸钠组分为对照组、OPA1 si RNA干预组、Scra si RNA干预组、OPA1 si RNA+NAC干预组。通过流式细胞仪检测各组心肌细胞在不同时间点的凋亡水平,q-PCR法检测心肌细胞中OPA1m RNA的表达情况,DHE染色法与ELISA试剂盒测定心肌细胞中活性氧簇(reactive oxygen species,ROS)水平。结果心肌细胞凋亡水平随着软脂酸钠的浓度和干预时间逐渐增加(P<0.05)。与对照组相比,高脂干预明显抑制心肌细胞中OPA1的表达,同时显著地促进ROS生成(P<0.05)。通过OPA1 si RNA干扰OPA1的表达水平后,高脂诱导的心肌细胞凋亡与ROS生成进一步增加(P<0.05);相反地,抗氧化剂N-乙酰半胱氨酸(N-acetyl-L-cysteine,NAC)逆转了上述OPA1抑制所导致的心肌细胞凋亡。结论高脂血症会进一步增加糖尿病心肌细胞的易损性,OPA1可以通过抑制氧化应激反应促进伴有高脂血症糖尿病条件下的心肌细胞存活。

Objective To investigate the effect of high fat and high glucose on cardiomyocytes and explore the role of optical atrophy-1 （OPAl） in the process. Methods Cardiomyocytes cultured with high- glucose medium underwent sodium palmitate intervention for 8 and 16 h, and were divided into 3 groups： high glucose ＋0 μmol/L sodium palmitate group, high glucose ＋ 200 μmol/L sodium palmitate group, and high glucose ＋ 400 μmol/L sodium palmitate group. Then, high glucose ＋ 400 μmol/L sodium palmitate group was further divided into 4 subgroups： control subgroup, OPAl siRNA subgroup, Scra siRNA subgroup, and OPAl siRNA ＋ N-acetyl-L-cysteine （NAC） subgroup. The apoptosis of cardiomyocytes was measured by flow cytometry at given time points. The mRNA expression of OPAl was determined by q-PCR, and the levels of reactive oxygen species （ROS） were detected by DHE staining and ELISA. Results The apoptotic ratio of cardiomyocytes was gradually increased in a dose- and time-dependent manner （P 〈 0. 05 ）. Moreover, compared with the control subgroup, high fat obviously inhibited the expression of OPAl in the cardiomyocytes and significantly aggravated the generation of ROS （P 〈 0. 05 ）. Most importantly, the knockdown of OPAl further aggravated the cardiomyocyte apoptosis and the level of ROS induced by high fat （P 〈 0. 05 ）. In contrast, these effects mentioned above were reversed by the application of antioxidant NAC （P 〈 0. 05 ）. Conclusion Hyperlipidmia increases the vulnerability of diabetic cardiomyocytes, and OPAl can improve cardiomyocyte survival in diabetic hyperlipidmia via inhibiting oxidative stress.