尼可地尔超极化心脏停搏心肌保护剂量-效应关系的实验研究

Experimental study on the dose-response relation of myocardial protection: hyperpolarized cardioplegic arrest with nicorandil

目的 :对不同浓度尼可地尔心肌麻痹液超极化心脏停搏心肌保护的剂量 -效应关系进行研究 ,选择最适心肌保护剂量。 方法 :实验分 6组 ,即对照组 (去极化心脏停搏组 )、5种不同浓度 (2 5、5 0、10 0、12 5和 15 0 μm ol/L)尼可地尔超极化心脏停搏组。 4℃心肌麻痹液 (40 ml/kg)诱停离体鼠心 ,每隔 30 min重复灌注心肌麻痹液 (2 0 m l/kg) ,(15± 1)℃心脏停搏 12 0 m in后再灌注 ,离体心工作 30 min。记录心脏机械停搏时间、再灌注后心脏复跳情况、心功能恢复 (左室发展压、主动脉流量及左室压力微分 )、冠状循环灌注平均流量、心肌丙二醛 (MDA )含量、心肌超微结构的改变。 结果 :尼可地尔心肌麻痹液心肌保护呈类似抛物线形的剂量 -效应关系。尼可地尔浓度为 10 0μmol/L时 ,L VDP的恢复率最佳 ,心肌保护效果最好。 结论 :尼可地尔超极化心脏停搏心肌保护的最适心肌保护剂量为 10 0μm ol/ L。

Objectives:Dose response effect of nicorandil cardioplegia at various concentrations was studied to optimize its myocardial protective effect. Methods: Forty eight isolated working rat hearts were divided into 6 groups randomly. They were group A: control (depolarized cardiac arrest with St. Thomas solution No.2), group B,C,E,F and G: hyperpolarized cardiac arrest (nicorandil concentration were 25,50,100,125 and 150μmol/L respectively). The hearts underwent a 120 minute hypothermic arrest (15±1)℃ with cardioplegia (40 ml/kg) and reinfused with cardioplegia (40 ml/kg) at interval of 30 minutes. Mechanical arrest time, cardiac functional recoveries, myocardial content of malondialdehyde (MDA) and ultrastructure were measured. Results:The protective effect of nicorandil cardioplegia was dose related. Conclusions:The optimal concentration of nicorandil in cardiplegia may be 100μmol/L for myocardial protection.