吡那地尔预处理对缺血心肌的保护效果

目的观察心肺转流(cardiopulmonory bypass,CPB)下,ATP敏感性钾通道开放剂(KCOs)吡那地尔(pinacidil)预处理分别对常温和低温高钾停跳心肌的保护作用.方法18只犬均分为三组,CPB心脏高钾停跳,全心缺血60 min,恢复灌注30 min.常温吡那地尔组(NP组)、低温吡那地尔组(HP组)CPB前主动脉根部灌注浓度为10 μmol/L的吡那地尔5 min.对比观察阻断主动脉前、后心肌超微结构、丙二醛(MDA)含量、血清心肌酶含量以及血液动力学的变化.结果(1)电镜:HP组除阻断60min外的其他时点心肌的正常线粒体及糖原含量均接近缺血前水平,明显高于C组和NP组;(2)心肌MDA的含量:HP组阻断30 min和开放20 min以及NP组开放20 min与C组有显著性差异;(3)血清心肌酶:HP组,除阻断30 min,CK-MB均明显低于同期C组;(4)血液动力学变化:HP组开放循环后心输出量(CO)、左室搏出功(LVSW)恢复比C组迅速.结论吡那地尔明显增强低温CPB心肌缺血-再灌注期超微结构的保护效果.

Effects of ATP-sensitive potassium channel openers on myocardial protection during normothermic or hypothermic cardiopulmonory bypass

Objective To study whether pinacidil,an ATP-sensitive potassium channel opener,could enhance protection of the myocardium from ischemia reperfusion injury during normothermic or hypothermic cardiopulmonory bypass(CPB).Methods Eighteen dogs were randomly divided into control group(group C),normothermia pinacidil group(group NP )and hypothermia pinacidil group( group HP).After CPB and cardioplegic arrest,glodal ischemia of the hearts was sustained for 60 min and then followed by reperfusion 30 min.In group HP and group NP,pinacidil was infused 15 min before cardioplegic heart arrest.Group C and group HP were arrested with cold cardioplegia during hypothermic CPB and group NP with normothermic cardioplegia during normothermic CPB.Ultrastucture and lipid peroxide of the myocardium,serum levels of the enzymeand hemodynamics were measured.Results In group HP,the percentage of normal mitochondria and glycogen level were not changed significantly after ischemia at all time points except for the time of clamping 60 min,and was higher markedly than those in group C.MDA level of group C was obviously higher than that of group HP during ischemic 30 min and reperfusion 20 min and that of group NP after reperfusion for 20 min.The levels of CK-MB were obviously higher in group HP than the values in group C at all time points except for the time of 30 min clamping.The recovery of CO and LVSW after clamp releasing in group HP was quicker than that.Conclusion pinacidil may enhance myocardial protection of cold cardioplegia during hypothermic CPB.