目的:研究心肌缺血-再灌注所致单相动作电位振幅(MAPA)改变与心肌损伤程度的相关性.方法:选择新西兰家兔作为实验动物并随机分为对照组和缺血再灌注组(I/R组),建立心肌缺血再灌注损伤模型后分离心脏并在Langendorff灌流系统内测定心肌内膜层、中膜层、外膜层的MAPA;另取血清标本及心肌组织,测定心肌损伤分子的含量.结果:I/R组动物心肌内膜层、中膜层、外膜层的MA-PA水平均显著高低于对照组;I/R组动物血清中CK-MB、cTnI、cTnT、MDA的含量以及心肌组织中Bax、Caspase-3、Caspase-9的mRNA表达量均显著高于对照组且与心肌内膜层、中膜层、外膜层的MAPA水平呈负相关,血清中SOD、GSH-Px、HO-1的含量以及心肌组织中Bcl-2、Bcl-xL的mRNA表达量显著低于对照组且与心肌内膜层、中膜层、外膜层的MAPA水平呈正相关.结论:心肌缺血-再灌注会引起MAPA降低且与心肌氧化应激损伤及凋亡密切相关.%Objective:To study the correlation between myocardial ischemia - reperfusion-induced monophasic action potential amplitude (MAPA)change and myocardial damage.Methods:New Zealand rabbits were selected as experimental ani-mals and randomly divided into control group and ischemia-reperfusion group (I/R group),myocardial ischemia-reperfusion injury models were established,then the heart was separated and the MAPA of myocardial intima layer,media layer and outer layer were determined in Langendorff perfusion system;serum samples and myocardial tissue were collected to determine the contents of myocardial injury molecules.Results:MAPA levels of myocardial intima layer,media layer and outer layer of I/R group were significantly lower than those of control group;CK-MB,cTnI,cTnT and MDA contents in serum as well as Bax, Caspase-3 and Caspase-9 mRNA expression in myocardial tissue of I/R group were significantly higher than those of control group and negatively correlated with MAPA levels of myocardial intima layer,media layer and outer layer while SOD,GSH-Px and HO-1 contents in serum as well as Bcl-2 and Bcl-xL mRNA expression in myocardial tissue were significantly lower than those of control group and positively correlated with MAPA levels of myocardial intima layer,media layer and outer layer.Con-clusion:Myocardial ischemia-reperfusion can induce the decrease of MAPA and is closely related to myocardial oxidative stress injury and apoptosis.
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