后适应在兔心肌缺血再灌注损伤中的实验研究

目的：观察缺血后适应对兔心肌缺血再灌注损伤（IRI）的保护作用。方法将30只新西兰大白兔随机分为缺血-再灌注组（IR组），缺血后适应组，后适应加5-羟基癸酸盐（5-HD）组，延迟后适应组及假手术组5组，每组6只。采用硫代巴比妥酸比色法检测5组大白兔心肌组织丙二醛含量，依文思兰加氯化四氮唑兰双重染色法及称重法测定心肌梗死范围大小。结果丙二醛含量缺血后适应组显著低于IR组和延迟后适应组（均P＜0.01），与后适应加5-HD组相近，但显著高于假手术组（P＜0.05）。心肌梗死面积在IR组、后适应加5-HD组、延迟后适应组之差异无统计学意义（P＞0.05），但大于缺血后适应组，差异均有显著统计学意义（均P＜0.01）。结论缺血后适应在兔心肌IRI模型中有明显的心肌保护作用；特异性线粒体ATP敏感钾通道抑制剂5-HD可完全取消后适应的心肌保护作用；延迟5min后实行后适应操作其保护作用完全消失。

Protection effects of postconditioning on myocardial ischemia-reperfusion injury in rabbits

Objective To investigate the protection effects of ischemic postconditioning on myocardial ischemi-a-reperfusion injury in rabbits. Methods 30 male New Zealand rabbits were randomly divided into ischemia-reperfusion （IR） group, postconditioning group, postconditioning＋5-hydroxydecanoate （5-HD） group, delayed postconditioning group and sham group. The content of malondialdehyde （MDA） was measured by thiobarbituric acid colorimetry and myocardial infarct size was determined by Evans blue and tetranitroblue tetrazolium chloride and weighting method. Results The content of MDA in postconditioning group was significantly lower than that of IR and delayed postconditioning groups （al P＆lt;0.01）, similar to that of postconditioning＋5-HD group, but significantly higher than that of sham group（P＆lt;0.05）. The my-ocardial infarct size was significantly larger in IR, postconditioing＋5-HD and delayed postconditioning groups than in post-conditioning group （P＆lt;0.01）. There was no significant difference among the former 3 groups. Conclusion Ischemic post-conditioning may protect rabbit myocardium from IR injury. This cardioprotective effect wil disappear when postconditioning begins 5 minutes later after onset of reperfusion, or wil be abolished by specific mitochondrial ATP-sensitive potassium channel blocker 5-HD 5.