缺血预处理对家兔缺血再灌注损伤心肌的延迟保护作用

目的　探讨缺血预处理对家兔缺血再灌注损伤心肌的延迟保护作用。方法　 2 4只健康家兔 ,随机分为假手术组(Sham)、缺血再灌注组 (I/R)和缺血预处理组 (IP) ,每组 8只 ,分别预处理 2 4h后行心肌缺血 60min ,再灌注 12 0min ,观察缺血心肌形态结构变化、缺血区面积和危险区面积、血清腺苷 (Adenosine)、降钙素基因相关肽 (CGRP)含量。结果　I/R家兔部分心肌纤维断裂 ,有灶性出血 ,心肌间质大量炎性细胞浸润 ,血清腺苷和CGRP含量显著下降 (P <0 0 1) ;缺血预处理组部分心肌纤维呈波浪状 ,肌浆分布不匀 ,心肌间质无出血 ,有数量不等炎性细胞浸润 ,但心肌结构基本正常 ,仅少数线粒体有轻度水肿 ;并能显著缩小缺血再灌注损伤家兔心肌梗死危险区面积和心肌缺血梗死 ,血清腺苷和CGRP含量升高 ,与Sham组和I/R组比较 ,差异均有显著性意义 ( P <0 0 1)。结论　缺血预处理对家兔缺血再灌注损伤心肌有明显的延迟保护作用 ,其机制与腺苷和降钙素基因相关肽作用有密切的关系。

Delayed Protection of Ischemic Preconditioning against Myocardial Ischemia-reperfusion Injury in Rabbits

Objective To explore the delayed protection of ischemic preconditioning against myocardial ischemia-reperfusion injury in rabbits. Methods Twenty four healthy rabbits were randomly into sham, ischemia-reperfusion(I/R) and ischemic preconditioning(IP) groups, each group containing 8 rabbits. After 24h IP, rabbits in IP group received 60 min coronary artery occlusion followed by 120 min reperfusion. Myocardial morphological changes were observed by optics microscope and electron microscope, infarction size and the area at risk were determined by triphenyltetrazolium chloride(TTC) and Evan's blue dye, and concentrations of adenosine and calcitonin gene-related peptide(CGRP) in serum were assayed. Results There were a few of cardial fibers ruptured, focus hemorrhage and a mass of inflammatory cell infiltration, and the concentrations of adenosine and CGRP in serum also decreased in rabbits of I/R group. Above changes were improved in rabbits of IP group, and infarction size and the area at risk markedly reduced compared with sham group and I/R group(P<0 01). Conclusions Ischemic preconditioning can induce delayed protection against myocardial ischemia-reperfusion injury in rabbit, the mechanism of which may be related to promoting the release of endogenous adenosine and CGRP.