大鼠心肌缺血再灌注损伤对心肌细胞膜Na^+-K^+-ATP酶亚基基因表达的影响与意义  

The Significance and Effect of Myocardial Ischemia Reperfusion Injury on Gene Expression of Na^+-K^+-ATPase Isoforms in Rat

作　　者：储岳峰[1] 柯永胜[1] 俞国华[1] 杨浩[1] 

机构地区：[1]皖南医学院弋矶山医院心内科,安徽省芜湖市241001

出　　处：《中国动脉硬化杂志》2007年第3期173-177,共5页Chinese Journal of Arteriosclerosis

基　　金：安徽省自然科学基金资助(050430707);安徽省教育厅自然科学基金资助(2005kj299)

摘　　要：目的观察心肌缺血再灌注损伤大鼠心肌组织内洋地黄素水平、ATP酶活性、线粒体Ca2+浓度以及Na+-K+-ATP酶各亚基基因表达的改变,探讨内洋地黄素在心肌缺血再灌注损伤细胞内钙超载中的可能作用及其机制。方法32只雄性SD大鼠随机分成假手术组,心肌缺血再灌注组,生理盐水组,维拉帕米组4组,每组8只。取缺血区左心室心肌检测心肌匀浆内洋地黄素水平、心肌细胞膜Na+-K+-ATP酶和Ca2+-Mg2+-ATP酶活性、线粒体Ca2+浓度;分别采用RT-PCR及Westernbloting方法检测心肌Na+-K+-ATP酶α1、α2、α3和β1亚基mRNA及蛋白水平基因表达的改变。结果心肌缺血再灌注时,心肌组织内洋地黄素水平明显升高,心肌细胞膜Na+-K+-ATP酶和Ca2+-Mg2+-ATP酶活性显著下降,线粒体Ca2+浓度升高,Na+-K+-ATP酶α1、α2、α3和β1亚基mRNA及蛋白水平基因表达均明显下降;维拉帕米预处理除显示降低线粒体Ca2+浓度外,对其它各项指标无明显影响。结论心肌缺血再灌注能促进心肌内洋地黄素分泌增加,后者可能通过影响心肌细胞膜上的Na+-K+-ATP酶α1、α2、α3和β1亚基基因表达,抑制Na+-K+-ATP酶活性,导致线粒体内Ca2+超载,从而介导心肌缺血再灌注损伤。确切的作用机制有待于更深入研究。Aim To investigate the mechanism of intracellular calcium overload of endoxin mediating myocardial ischemia reperfusion(MIR) injury, the changes of endoxin level, ATPase activities, intramitochondrial Ca2+ concentration and gene expression of Na+-K+-ATPase isoforms in myocardium of rats with MIR were observed. Methods Thirty-two male Sprauge Dawley rats were randomly divided into 4 groups. Sham operation group (control group): silk suture threading the left anterior descending coronary artery without ligature; MIR group (MIR):left anterior descending coronary artery was subjected to 30 min ligation followed by 45 min reperfusion; normal saline group (NS):MIR model was given 5 mL/kg-1 normal saline; verapamil group (Ver): MIR model was given 5 mg/kg verapamil. Drug and NS were injected into vessel via femoral vein within 5 min before reperfusion. After reperfusion left ventricle myocardium samples were processed immediately in order to measure the activities of Na+-K+-ATPase and Ca2+-Mg2+-ATPase, endoxin level, intramitochondrial Ca2+ concentration and the changes of mRNA and protein levels of α1, α2, α3 and β1 isoforms of Na+-K+-ATPase were measured by RT-PCR and western-blot technology respectively. Results After MIR, the level of endoxin in myocardium was obviously increased, the activities of Na+-K+-ATPase and Ca2+-Mg2+-ATPase in myocardial membrane were significantly decreased while the concentration of intramitochondrial Ca2+ increased, the levels of mRNA and protein of the α1, α2, α3 and β1 isoforms of Na+-K+-ATPase were reduced markedly. Verapamil had only effect of reducing the concentration of intramitochondrial Ca2+. Conclusion MIR resulted in increase of myocardial endoxin secretion. The latter could depress the activity of Na+-K+-ATPase by changing the gene expression of α1, α2, α3 and β1 isoforms of Na+-K+-ATPase in myocardial membrane, and induce intramitochondrial Ca2+ overload, thereby mediate MIR injury.

关 键 词：病理学与病理生理学 缺血再灌注损伤 内洋地黄素 钠钾依赖式ATP酶 线粒体 钙超载 逆转录聚合酶链反应 蛋白质斑迹法 

分 类 号：R363[医药卫生—病理学]