尼可地尔超极化心脏停搏心肌保护的实验研究

Experimental study on myocardial protection: Hyperpolarized cardioplegic arrest with nicorandil

目的：评估尼可地尔（Ｎｉｃｏｒａｄｉｌ）超极化心脏停搏心肌保护的有效性，并与高钾心肌麻痹液去极化心脏停搏的心肌保护效果进行比较。方法：实验分３组，即对照组、去极化心脏停搏组、超极化心脏停搏组。１０ｍｌ４℃心肌麻痹液诱停离体鼠心，每３０ｍｉｎ重复灌注心肌麻痹液５ｍｌ，在（１５±１）℃下心脏停搏１２０ｍｉｎ，再灌注后离体心工作３０ｍｉｎ。记录心脏机械停搏时间、再灌注后心脏复跳情况、心功能指标恢复（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、电镜下心肌超微结构的改变。结果：超极化心脏停搏组对心功能恢复、冠状循环灌注平均流量及心肌组织超微结构的保护效果优于去极化心脏停搏组（Ｐ＜０．０５），心肌ＭＤＡ含量低于去极化心脏停搏组（Ｐ＜０．０１）。

Objectives: To evaluate myocardial protective effect of hyperpolarized cardioplegic arrest, its myocardial protective efficiency was compared with traditional depolarized cardiac arrest with St. Thomas No.2 solution in isolated working rat heart. Methods: Twenty four isolated working rat hearts were divided into 3 groups randomly. There were group A: control, group B: depolarized cardiac arrest with St. Thomas solution No.2, group C: hyperpolarized cardiac arrest ( nicorandil 100 μmol/L). The hearts underwent a 120 minute hypothermic arrest (15±1℃) with induction of 10 ml cardioplegia and reinfusion of 5 ml cardioplegia every 30 minutes. Mechanical arrest time, cardiac functional recoveries, myocardial content of malondialdehyde (MDA) and ultrastructure were measured. Results: There were statistically significant differences between B and C group in the recovery of cardiac function, myocardial content of MDA, and ultrastucture of mitochondrial membranes and cristae. Conclusions : The effect of myocardial protection with nicorandil is superior to that with St. Thomas No.2 solution.