猪缺血再灌注损伤与心肌细胞凋亡的实验研究

目的探讨猪心肌梗死不同区域细胞凋亡的分布。方法滇南小耳猪10只,随机分为两组,每组5只。(1)假手术组(S组),在X线的监控下,经右股动脉置入冠状动脉球囊导管至左前降支,不行冠脉封堵心肌缺血;(2)缺血再灌注组(I/R组),冠脉球囊扩张阻断冠脉血流60min致心肌缺血,撤除球囊恢复冠脉灌注。再灌注72h,行猪心肌末端标记法(TUNEL法)检测凋亡细胞及免疫组化法检测Bcl-2和Bax的蛋白表达。结果再灌注后72h,S组未发生心肌梗死及心肌细胞凋亡,I/R组在心肌梗死区、边缘区、非梗死区的心肌组织均存在细胞凋亡现象,梗死区和边缘区的心肌细胞凋亡指数(AI)明显高于非梗死区,且相应区域的Bax蛋白表达及Bax/Bcl-2比值均较非梗死区增加(P<0.05)。结论猪心肌缺血再灌注损伤后心肌梗死区、梗死边缘区、非梗死区均存在心肌细胞凋亡现象,细胞凋亡主要分布在梗死区和边缘区。

The experimental research of ischemia-reperfusion injury and myocardial apoptosis in swine

Objective To investigate the distribution of apoptosis on different area in pigs with myocardial infarction.Methods Ten Diannan small-ear pigs were divided into two groups(n=5) randomly: Sham-operated(S) group and ischemia-reperfusion(I/R) group.In S group,balloon catheter was positioned in the mid-distal left anterior descending(LAD) via right femoral artery under fluoroscopic guidance,without ischemia.In I/R group,the balloon was inflated and occluded the LAD for 60 minutes.At 72h after reperfusion,infarction size were measured by 2,3,5-triphenyltetrazolium chloride(TTC) staining.The apoptotic cells in the myocardium were determined with terminal deoxynucleotidyl transferase-mediated dUTP-fluorescence in nick end(TUNEL) method,and protein expression of Bcl-2 and Bax were detected by immunohistochemical analysis.Results At 72h after reperfusion,there was no myocardial infarction and apoptosis in S group.In I/R group,apoptotic index(AI) of infarcted zone and border zone were significantly higher than those in non-infarcted zone,as well as Bax protein expressions and Bax/Bcl-2 ratio increased greatly compared with that in non-infarcted zone(P<0.05).Conclusion There were apoptotic cells in infarcted zone,border zone and non-infarcted zone after I/R injury.Most of these apoptotic cells were in infarcted zone and border zone.