含钾通道开放剂的HTK液对大鼠心功能以及线粒体结构和功能的影响

Prolonged donor hearts preservation with pinacidil ： the role of mitochondria and mitochondrial adenosine triphosphate-sensitive potassium channels

目的观察含钾通道开放剂的供心保存液对心功能以及能量代谢、线粒体呼吸酶活性及超微结构的影响。方法将SD大鼠分为HTK组、Pi组、5HD组、1098组和5HD＋1098组。切取SD大鼠心脏，建立Langendorff灌注模型，平衡10min，然后按分组进行如下处理：HTK组心脏以Histidine-Tryptophan—Ketoglutarate液（HTK液）停搏；Pi组心脏以含0．5mmol／L吡那地尔（Pi）的HTK液停搏；1098组心脏以含0．5mmol／L Pi和100μmol／L HMR1098的HTK液停搏；5HD组心脏以含0．5mmol／L Pi和100μmol／L五羟葵酸（5HD）的HTK液停搏；5HD＋1098组心脏以含0．5mmol／LPi、100μmol／L 5HD和100μmol／L HMR1098的HTK液停搏。停搏后，将心脏置于各组相应的液体（4℃）中保存8h，然后用含氧的37℃克亨液（K-H液）再灌注60min。观察各组平衡末、保存末、再灌注末时的心功能、线粒体呼吸酶活性、心肌ATP含量及心肌细胞线粒体超微结构的改变。结果R组保存末、再灌注末的心功能（心率、左心室舒张末压、左心室发展压和冠状动脉流量）、心肌线粒体呼吸酶（NADH氧化酶、琥珀酸氧化酶、细胞色素C氧化酶）活性及ATP含量均优于其他各组（P〈0．01或P〈0．05），同时线粒体的结构改变也最轻。结论含Pi的HTK液能改善大鼠心脏保存效果；Pi对能量状态的维持以及对线粒体结构与功能的保护可能是其心肌保护的重要机制。

Objective To investigate the effects of pinacidil on isolated rat hearts preservation, and evaluate the roles of myocardial mitochondrial KATe channel （mitoKAwp） and the effects on mitochondria. Methods 120 SD rats were randomly divided into five groups （n = 24, 8 at every moment of stabilization,storage and reperfusion） as follows： （1） the group of HTK solution as the control group, （2） the group of HTK solution containing pinacidil （the Pi group）, （3） the group of HTK solution containing pinacidil and 5-hydroxydecanote （5HD, a selective mitochondrial KATP channel blocker, the 5HD group）, （4） the group of HTK solution containing pinacidil, Hoechst- Marion Roussel 1098 （HMR1098, a selective sarcolemmal KATP channel blocker, the 1098 group）, and （5） the group of HTK solution containing pinacidil, 5HD and HMR1098 （the 5HD ＋ 1098 group）. The Langendorff perfusion models were established. All hearts were arrested with the abovementioned five preservation solutions in a Langendorff apparatus respectively and subsequently dipped into the same solution for 8 h at 4 ℃ followed by 60 min of reperfusion. The hemodynamics, mitochondrial respiratory function, ATP levels, cardiac troponin I release and myocardial ultrastructure were examined. Results Compared with the other groups, heart performance parameters, mitochondrial respiratory enzyme activity and myocardial ATP contents in the Pi group were significantly improved as well as the myocardial mitochondria Flameng score. The protection was almost abolished by the addition of 5HD and moderately decreased by HMR1098. Conclusion Pinacidil may further improve the myocardial protection efficacy of donor heart preservation. Energy status preservation is one of important mechanisms of pinacidil and the effect depends more on mitoehondrial than on sarcolemmal potassium adenosine triphosphate channels.