大鼠心肌缺血再灌注损伤对心肌细胞膜钠泵表达的影响  

Changes of myocardial membrane gene expression of natrium pump isoforms in rat with myocardial ischemia reperfusion injury

作　　者：柯永胜[1] 储岳峰[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

出　　处：《中国临床药理学与治疗学》2007年第3期295-298,共4页Chinese Journal of Clinical Pharmacology and Therapeutics

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

摘　　要：目的观察心肌缺血再灌注(MIR)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,并观察钙通道阻滞剂维拉帕米对其影响,探讨内洋地黄素在MIR损伤细胞内钙超载中的可能作用及其机制。方法24只雄性SD大鼠随机分成3组,每组8只。假手术组丝线穿过左冠状动脉前降支,但不结扎;缺血再灌注组(MIR组)结扎左冠状动脉前降支30min,再灌注45min;维拉帕米组MIR模型+5mg/kg维拉帕米,维拉帕米于再灌注前5min经股静脉注射。取缺血区左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;免疫组化方法检测心肌Na+-K+-ATP酶α1、α2、α3和β1亚基蛋白水平表达的改变。结果MIR损伤时,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亚基蛋白水平表达均明显下降;维拉帕米除具有降低线粒体Ca2+浓度外,对缺血再灌注引起的其它各项异常指标无明显改善作用。结论MIR促进机体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。AIM： Changes of endoxin level, ATPase activities, intramitochondrial Ca^2＋ concentration, and gene expression of Na^＋ -K^＋ -ATPase isoforms in myocardium of rats with MIR and effect of verapamil were observed, in order to investigate mechanism of endoxin mediating intracellular calcium overload of myocytes. METHODS： Twenty four male Sprauge Dawley rats were randomized into 3 groups. Sham operation group： silk suture was threaded 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; verapamil group： MIR model was given 5 mg/kg verapamil. Verapamil was injected via femoral vein 5 min before reperfusion. Left ventricle myocardium samples were processed immediately after reperfusion in order to measure the activities of Na^＋ - K^＋ -ATPase and Ca^2＋ -Mg^2＋ -ATPase, endoxin level, and intramitochondrial Ca^2＋ concentration. The levels of α1, α2,α3 and β1 isoforms of Na^＋ -K^＋ -ATPase were measured by immunohistoehemieal assay. RESULTS： After MIR, the level of endoxin in myoeardium was substantially increased; the activities of Na^＋ -K^＋ -ATPase and Ca^2＋- Mg^2＋ -ATPase in myocardial membrane were significantly decreased while the concentration of intramitochondrial Ca^2＋ was increased; the levels of the α1, α2,α3 and β1 isoforms of Na^＋-K^＋-ATPase were reduced markedly. Verapamil had only effect on reducing the concemration of intramitochondrial Ca^2＋ . CONCLUSION： MIR increases endoxin secretion. The latter may 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, inducing intramitochondrial Ca^2＋ overload.

关 键 词：内洋地黄素 缺血再灌注损伤 心肌 腺苷三磷酸酶/亚基 免疫组化 

分 类 号：R965.2[医药卫生—药理学]