激活K阿片受体与远程预处理诱导心肌缺血耐受的作用

目的:比较K阿片受体激动剂U50488H预处理与远程预处理诱导心肌缺血耐受对心肌梗塞(MI)范围与心肌酶的影响。方法:32只雄性新西兰大白兔随机分成四组(各组8例):对照组、U50488H组、远程缺血预处理(RPC)组和选择性K阿片受体阻断剂(Nor-BNI)+U50488H组。对照组心肌缺血前1.5h静脉给予戊巴比妥钠30mg/kg;RPC组在心肌缺血前1.5h静脉给予戊巴比妥钠30mg/kg麻醉动物后,行双后肢短暂缺血预处理2次(充气式压力止血带环扎双后肢腘窝上1/3,压力26.6kPa,每次10min,间隔10min);U50488H组在心肌缺血前105min静脉注射U50488H1.5mg/kg,余同RPC组;Nor-BNI+U50488H组在预处理前15min给予Nor-BNI2mg/kg,余同U50488H组。各组最后制作急性心肌缺血模型:冠状动脉左前降支完全闭塞45min,松开结扎圈再灌注2h。依据美蓝、TTC组织染色,观察各实验组MI质量比、肌钙蛋白T、心肌酶的变化。结果:U50488H可模拟RPC对心肌的保护作用,较对照组明显减少心肌缺血-再灌注损伤所致的MI(0.15±0.11)g∶(0.29±0.11)g],肌钙蛋白T冠脉阻闭45min(3.86±1.19)ng/ml∶(9.16±2.82)ng/ml],心肌酶的含量,P均0.01。该作用可被选择性K阿片受体阻断剂Nor-BNI所阻断。结论:RPC诱导心肌缺血耐受与K阿片受体激活具有密切关系,激活K阿片受体是RPC诱导心肌缺血耐受的机制之一。

Effect of activated K-opioid receptor and remote preconditioning on myocardium ischemia tolerance

Objective:To study the effects of U50488H (a selective K-opioid receptor agonist) on the size of myocardial ischemic-reperfusion and the plasma contents of myocardium enzyme compared with the protection of remote ischemic preconditioning from myocardial ischemia in rabbits.Methods:A total of 32 male New Zealand white rabbits were randomly divided into four groups:remote preconditioning group(RPC),ischemia-reperfusion group(control),U50488H group and K-opioid receptor blocking agent (Nor-BNI)+U50488H group r...