金丝桃苷预处理对心肌缺血再灌注性心律失常大鼠心肌ATP酶活性和Cx43、Kir2.1表达的影响

摘要

目的 金丝桃苷具有抗脑缺血、降低心肌梗死面积等作用,通过构建大鼠心肌缺血再灌注(I/R)模型,进行金丝桃苷预处理对I/R大鼠室性心律的影响以及相应作用机制的研究.方法 选择雄性SD大鼠,随机分为假手术组、模型组、金丝桃苷(50 mg/kg)组(n=15),结扎冠状动脉左前降支缺血30 min恢复灌注构建I/R模型,金丝桃苷组于缺血前10 min腹腔注射金丝桃苷50 mg/kg,记录缺血前10 min、后30 min,再灌注30、60、120 min (To、T1、T2、T3、T4)大鼠心率(HR)、平均动脉压(MAP)、心率收缩压乘积(RPP),观察心律失常情况,ELISA法测定血清肌酸激酶-同工酶(CK-MB)和肌钙蛋白(cTnI)水平,分光光度法测定Na+-K+-ATP酶和Ca2+-Mg2+-ATP酶水平,HE染色观察心肌组织变化,免疫组化法测定心肌缝隙连接蛋白(Cx43)表达,Western blot测定Kir2.1蛋白表达.结果 在T1、T2、T3、T4,模型组HR、MAP、RPP显著低于假手术组,金丝桃苷组HR、MAP、RPP高于模型组(P＜0.05);模型组、金丝桃苷组心律失常评分、CK-MB、cTnI高于假手术组,Na+-K+-ATP酶和Ca2+-Mg2+-ATP酶活性、Cx43和Kir2.1蛋白表达低于假手术组(P＜0.05),金丝桃苷组心律失常评分、CK-MB和cTnI水平低于模型组,Na+-K+-ATP酶和Ca2+-Mg2+-ATP酶水平、Cx43和Kir2.1蛋白表达高于模型组(P＜0.05).结论 金丝桃苷有减轻I/R大鼠室性心律失常的作用,其作用可能与增加Na+-K+-ATP酶和Ca2+-Mg2+-ATP酶活性,上调Cx43和Kir2.1蛋白表达有关.%AIM To investigate the effects of hyperoside,an anti-arrhythmic agent capable of reducing myocardial infarct size,on arrhythmic rats induced by ischemia-reperfusion (I/R) and the corresponding mechanism.METHODS Male SD rats were randomly assigned to sham operation group,model group and hyperoside group (50 mg/kg,n =15).The I/R model was reconstructed by the ligation of left anterior descending coronary artery for 30 min ischemia.Rats in the hyperoside group were injected with 50 mg/kg hyperoside intraperitoneally 10 min before ischemia.Heart rate,mean arterial pressure (MAP) and heart rate systolic blood pressure product (RPP) at time points of 10 min before ischemia (T0),30 min after ischemia (T1),30 min (T2),60 min (T3),120 min (T4) after reperfusion were recorded.ELISA method was used to determine serum CK-MB and cTnI,spectrophotometry to measure Na+-K+-ATPase and Ca2+-Mg2+-ATPase levels,HE staining to observe myocardial tissue changes,immunohistochemistry to investigate Cx43 protein,and Western blot to detect Kir2.1 protein expression.RESULTS At T1,T2,T3 and T4,the model group demonstrated significantly lower HR,MAP and RPP than those in the sham operation group (P ＜ 0.05),whereas the hyperoside group had higher HR,MAP and RPP than the model group.Both hyperoside group and the model group shared significantly higher arrhythmia score,levels of CK-MB and cTnI than the sham operation group (P ＜ 0.05) while their lower activities of Na +-K +-ATPase and Ca2+-Mg2+-ATPase,protein expressions of Cx43 and Kir2.1 than the sham operation group were noticed as well.But the hyperoside group displayed its lower arrhythmia score,levels of CK-MB and cTnI,and yet higher activities of Na +-K +-ATPase and Ca2 +-Mg2 +-ATPase,protein expressions of Cx43 and Kir2.1 than the model group (P ＜0.05).CONCLUSION Hyperoside in improving ventricular arrhythmia of I/R rats may contribute to the activity restoration of Na +-K +-ATPase and Ca2 +-Mg2 +-ATPase,and the up-regulation of Cx43 and Kir2.1 protein expressions.