【摘要】 目的 观察不同类型ATP敏感性钾通道开放对高钾停跳离体兔心缺血再灌注损伤的保护作用，并探讨可能的保护机制。方法 采用离体兔心Langendorff灌注实验模型，离体兔心40只随机等分成五组(n=8)：对照组(C组)、Pinacidil组(P组)、Diazoxide组(D组)、5-HD+Pinacidil组(HP组)、5-HD+Diazoxide组(HD组)。离体兔心4℃标准St.Thomas停搏液(K+16mmol/L)至心脏停跳，45min后再灌注20min，药物于心脏停跳前灌注15min。对比观察Pinacidil、Diazoxide及其与5-HD合用时心脏的功能指标、冠脉血流量以及再灌注末心肌组织中腺苷酸含量、丙二醛(MDA)含量、超氧化物歧化酶(SOD) 活性和心肌酶的变化。结果 P组、D组、HP组再灌注后复跳时间、心功能的恢复率、心肌能量保存、SOD活性均显著高于C组，心肌酶、MDA的含量显著低于C组，HP组心功能的恢复、能量保存差于P组，心肌酶、MDA的含量高于P组。结论 肌纤维膜型(sarcKATP通道)和线粒体型(mitoKATP通道) KATP通道共同参与对心肌缺血再灌注损伤的保护作用,其中mitoKATP通道起主导作用。

    【关键词】 mitoKATP通道；缺血再灌注损伤；离体家兔；心脏

    The role of mitochondrial ATP sensitive potassium channel during ischemia-reperfusion in rabbit heart

    YE Ying,XU Tie,LV Jian-nong.

    The Center of Emergency,Affiliated Hospital of Xuzhou Medical College,Jiangsu 221002,China

    【Abstract】 Objective To investigate the protective effects of different ATP-sensitive potassium (KATP) channel opens, Pinacidil and Diazoxide , on myocardium injury in isolated rabbit hearts caused by ischemia/reperfusion and possible changes after application of ATP-sensitive potassium channel blocker,5-HD. Methods Observation was made on rabbit hearts perfused with a Langendorff apparatus. 40 rabbits were randomly divided into four selected groups: 1. Pinacidil;2. Diazoxide;3. 5-HD+Pinacidil;4. 5-HD+Diazoxide. All groups were subjected to 40 minutes occlusion, then followed by 20 minutes reperfusion as cardiac stopped functioning by cold cardioplegia. Any one of Pinacidil, Diazoxide , Pinacidil or Diazoxide mixed with 5-HD was infused 15 minutes before cardioplegic heart rested in experimental group.Hemodynamics variables, levels of adenine nucleotides and lipid peroxide of the myocardium were measured. Results (1)In Group P, Group D and Group HP, the recovery of myocardial contractility and heart rate were faster and MDA level of myocardium and had much lower levels of activities of cretinkinase (CK) and lactate dehydrogenase (LDH). Moreover levels of myocardial adenosine triphosphate (ATP)(P<0.05 or 0.01)were much higher.(2)In Group HP, however, the recovery of myocardial contractility and heart rate could not be as good as Group P, MDA level of myocardium and release amount of albumen was higher than P group. Conclusion The ATP-sensitive potassium channel openes may enhance myocardial protection against ischmia /reperfusion injury. The above effect of myocardial protection was only partially closed down by ATP-sensitive potassium channel blocker: 5-HD. These results shows that selective pharmacological agents implicate mitochondria and sarcolemmal KATP channels are not important in ischemic cardioprotection. ......