促分裂原活化蛋白激酶磷酸酶1对肿瘤坏死因子-α介导的心肌损伤的保护作用

Protective effect of mitogen-activated protein kinase phosphatase 1 on tumor necrosis factor-α-mediated myocardial injury

目的探讨促分裂原活化蛋白激酶磷酸酶1(MKP1)对肿瘤坏死因子-α(TNF-α)诱导心肌损伤的影响及其机制。方法将野生型(WT)和MKP1转基因(MKP1)小鼠(购自武汉华联科生物技术有限公司)各自随机分为两组:WT、WT+TNF-α组和MKP1、MKP1+TNF-α组。WT+TNF-α组和MKP1+TNF-α组的小鼠按6 mg/kg的剂量腹腔注射TNF-α;WT组和MKP1组的小鼠腹腔注射等量的生理盐水。检测各组小鼠心肌MKP1表达、心肌损伤标志物水平、心肌细胞线粒体分裂相关蛋白、抗氧化剂和呼吸复合物表达以及线粒体凋亡情况,采用t检验分析组间差异。结果与WT+TNF-α组比较,MKP1+TNF-α组的小鼠心肌线粒体分裂动力蛋白相关蛋白1(Drp1)和线粒体分裂因子(Mff)相对表达下调(Drp1:1.80±0.20比1.00±0.30、t=-10.134、P<0.05;Mff:2.80±0.20比1.10±0.30、t=-8.313、P<0.05),差异有统计学意义,还原型谷胱甘肽(GSH)、超氧化物歧化酶(SOD)及谷胱甘肽过氧化物酶(GPX)水平升高[GSH:(29±2)nmol/mg比(49±3)nmol/mg、t=12.127、P<0.05;SOD:(2.2±0.1)U/mg比(8.1±0.2)U/mg、t=10.301、P<0.05;GPX:(50±4)U/mg比(172±6)U/mg、t=11.136、P<0.05],差异有统计学意义,线粒体呼吸复合物(complex)Ⅲ和ⅢⅡ相对表达上调(complexⅢ:1.00±0.20比2.20±0.12、t=10.715、P<0.05;complexⅡ:1.10±0.09比1.90±0.08、t=8.312、P<0.05),差异有统计学意义,天冬氨酸蛋白水解酶-9(Caspase-9)和B细胞淋巴瘤/白血病-2相关X蛋白(bax)相对表达下调(Caspase-9:2.20±0.11比1.15±0.09、t=-5.210、P<0.05;bax:2.30±0.12比1.42±0.09、t=-6.006、P<0.05),差异有统计学意义。结论TNF-α诱导心肌损伤的机制涉及线粒体的过度分裂、线粒体氧化还原平衡和能量代谢的破坏以及线粒体凋亡。而MKP1过表达可明显抑制这些不良反应的发生发展,保护线粒体功能,抑制心肌损伤。

Objective To investigate the effect of mitogen-activated protein kinase phosphatase 1(MKP1)on tumor necrosis factor-α(TNF-α)-induced myocardial injury.Methods Wild type(WT)and MKP1 transgene(MKP1)mice were randomly divided into 2 groups separately:WT group,WT+TNF-αgroup and MKP1 group,MKP1+TNF-αgroup.Mice in the WT+TNF-αgroup and the MKP1+TNF-αgroup were intraperitoneally injected with TNF-αat a dose of 6 mg/kg.Mice in the WT group and the MKP1 group were intraperitoneally injected with an equal amount of physiological saline.The MKP1 expression,myocardial injury marker level,myocardial mitochondrial division-associated protein 1(Drp1),antioxidant and respiratory complex expression and mitochondrial apoptosis were measured,and t-test was used to analyze differences between groups.Results As compared with WT+TNF-αgroup,MKP1+TNF-αgroup showed down-regulation of Drp1 and Mff expression(Drp1:1.80±0.20 vs.1.00±0.30,t=-10.134,P<0.05;Mff:2.80±0.20 vs.1.10±0.30,t=-8.313,P<0.05),increased expression of glutathione(GSH),superoxide dismutase(SOD)and glutathione peroxidase(GPX)[GSH:(29±2)vs.(49±3)nmol/mg,t=12.127,P<0.05;SOD:(2.2±0.1)vs.(8.1±0.2)U/mg,t=10.301,P<0.05;GPX:(50±4)vs.(172±6)U/mg,t=11.136,P<0.05],increased expression of mitochondrial respiratory recombinationⅢandⅡ(complexⅢ:1.00±0.20 vs.2.20±0.12,t=10.715,P<0.05;complexⅡ:1.10±0.09 vs.1.90±0.08,t=8.312,P<0.05),down-regulation of Caspase-9 and bax expression(Caspase-9:2.20±0.11 vs.1.15±0.09,t=-5.210,P<0.05;bax:2.30±0.12 vs.1.42±0.09,t=-6.006,P<0.05).Conclusion The mechanism of TNF-α-induced myocardial injury involves excessive division of mitochondria,mitochondrial redox balance,destruction of energy metabolism and mitochondrial apoptosis.MKP1 overexpression can significantly inhibit the development of these adverse reactions,protect mitochondrial function and inhibit myocardial damage.