缺血后处理对大鼠缺血再灌注心肌细胞凋亡的影响

Effect of ischemic postconditioning on myocardial apoptosis in rats with ischemic reperfusion

目的:观察缺血后处理对大鼠缺血再灌注心肌细胞凋亡的影响。方法:实验于2006-02/05在首都医科大学附属朝阳医院心脏中心实验室完成。选择健康SD大鼠48只,随机数字表法分为3组:假手术组、缺血再灌注组和缺血后处理组,每组16只。制备大鼠心肌缺血再灌注模型。缺血再灌注组,收紧结扎线缺血40min,放松结扎线再灌注240min;缺血后处理组,缺血40min后,再灌注10s,缺血10s,连续3个循环,然后再灌注239min;假手术组,开胸后穿线做套环,但不收紧结扎线。采用TUNEL技术检测心肌细胞凋亡率,同时测定血清肌酸激酶活性和心肌梗死范围。结果:纳入动物48只,均进入结果分析。①血清中肌酸激酶活性的测定:再灌注结束后缺血后处理组和缺血再灌注组肌酸激酶活性明显高于假手术组[分别为(13.54±1.50),(20.72±1.58),(2.90±0.28)μkat/L,P<0.01],缺血后处理组明显低于缺血再灌注组(P<0.01)。②心肌梗死范围:再灌注结束后缺血后处理组和缺血再灌注组心肌缺血区与左室面积比值无明显差异,缺血后处理组心肌坏死区与缺血区比值显著低于缺血再灌注组(分别为26.1±6.7,40.2±7.2,P<0.01)。③心肌凋亡细胞计数:再灌注结束后假手术组未见明显细胞凋亡(<5%),缺血后处理组心肌细胞凋亡率明显低于缺血再灌注组[分别为(12.5±2.9)%,(21.3±3.8)%,P<0.01]。结论:缺血后处理可减轻缺血再灌注损伤、其机制可能与减少心肌细胞凋亡有关。

AIM： To study the effect of ischemic postconditioning on myocyte apoptosis in rats with myocardial ischemia reperfusion （MIR）. METHODS： The experiment was conducted in the Central Laboratory of Heart, Chaoyang Hospital Affiliated to Capital University of Medical Sciences from February to May 2006. Forty-eight healthy SD rats were selected and randomly divided into 3 groups： Sham-operation group, ischemic reperfusion group and ischemic postconditioning group with 16 rats in each group, and rats were made into MIR models. Rats in the ischemic reperfusion group were ligated for 40-minute ischemia, and then reperfused for 240 minutes. Rats in the ischemic postconditioning group were treated for 40-minute ischemia, reperfused for 10 s and 10 s ischemia for three cycles, and then reperfused for 239 minutes. Rats in the sham-operation group were opened the chest to braid for ringer without deligation. The presence of apoptotic myocytes was detected by the method of terminal Deoxynucleotidyl transferase-mediated dUTP nick end labeling （TUNEL）. Meanwhile, the serum creatine kinase activity and myocardial infarct size were measured. RESULTS： A total of 48 animals were involved in the analysis of results. ①Determination of serum creatine kinase activity： it was obviously higher in the ischemic postconditioning group and ischemic reperfusion group after reperfusion than that in the sham-operation group [which were respectively （13.54±1.50）,（20.72±1.58）, （2.90±0.28） p, kat/L, P 〈 0.01], and it was significantly lower in the ischemic postconditioning group than that in the ischemic reperfusion group （P 〈 0.01）. ② Myocardial infarction size： The ratio of myocardial ischemic size and left ventricle after reperfusion in the ischemic postconditioning group and ischemic reperfusion group were fundamentally the same without significant differences, and it was lower in the ischemic postconditioning group than that in the ischemic reperfusion group （which were respectively 26.1±6.7,40.2±7.2,P 〈 0.01）. ③Number of apoptotic myocardial cells： There was no significant apoptosis found after the reperfusion in the sham-operation group （〈 5%）, and the apoptotic rate in the ischemic postconditioning group was remarkably lower than that in the ischemic reperfusion group [which were respectively （12.5±2.9）%, （21.3±3.8）%, P 〈 0.01]. CONCLUSION： Ischemic postconditioning can relieve the ischemic reperfusion injury, the mechanism of which may be related with the decreased myocardial apoptosis.