不同缺血时间对中国小型猪心肌缺血再灌注损伤的影响研究

Effects of various ischemia times on myocardial ischemia-reperfusion injury in the Chinese miniature swine model

目的探讨不同缺血时间对中国小型猪急性心肌缺血再灌注损伤的影响,为建立适合的小型猪心肌缺血再灌注模型提供依据。方法中国小型猪29只,随机分为假手术组(6只)、缺血30 min组(7只)、缺血60 min组(7只)及缺血90 min组(9只)。各组戊巴比妥钠麻醉后行左冠状动脉造影,后将球囊经导丝交换入冠脉左前降支中部,术中连续心电监护记录ST段改变情况、室颤及除颤次数,再灌注3 h后处死。于缺血前、再灌即刻、再灌后1 h、2 h及3 h采集超声心动图,描记心脏收缩功能左心室射血分数(left ventricular ejection fraction,EF)及左心室短轴缩短率(left ventricular fractional shortening,FS);检测血清肌酸激酶同工酶(creatine kinase isoenzyme,CKMB)、乳酸脱氢酶(lactate dehydrogenase,LDH)及超氧化物歧化酶(superoxide dismutase,SOD)活性,丙二醛(malondialdehyde,MDA)含量。TTC/伊文思蓝双重染色观察心肌梗死面积,硫磺素S染色法观察再灌后无复流面积。结果缺血90 min组动物死亡率较缺血30 min组、缺血60 min组高;随缺血时间增长,室颤及除颤次数明显增加(P<0.05,P<0.01);缺血90 min组再灌注3 h时EF值、FS值较其他组明显降低(P<0.05,P<0.01);模型组动物在心电图缺血性改变、心肌梗死及无复流面积、心肌组织染色及血清CK-MB、LDH、SOD、MDA含量方面无显著性差异。结论心肌缺血90 min再灌注小型猪模型的恶性心律失常及死亡率高,缺血30 min再灌注3 h条件建立的模型能复制临床疾病的特征性病变且死亡率低,适合于发病机制及药物作用研究。

Objective To investigate various ischemia times of myocardial ischemia-reperfusion injury(MI/RI)in Chinese miniature swine and provide the basis to establish the optimal model of MI/RI in Chinese miniature swine.Methods Twenty-nine Chinese miniature swine were randomly divided into a sham group(n=6),30 min ischemia group(n=7),60 min ischemia group(n=7),and 90 min ischemia group(n=9).After pentobarbital sodium anesthesia,left coronary angiography was performed in each model group,and a balloon was exchanged into the middle of the left anterior descending branch through a wire.We elevated the ST segment on a body surface electrocardiogram and the numbers of ventricular fibrillations and defibrillations during the operation.Left ventricular ejection fraction(EF)and left ventricular fractional shortening(FS)were recorded before the operation,before reperfusion,and at 1,2 and 3 h of reperfusion.Serum levels of creatine kinase isoenzyme(CK-MB),lactate dehydrogenase(LDH),superoxide dismutase(SOD)and malondialdehyde(MDA)were measured at the same time.The area of myocardial infarction was observed by double staining with TTC/Evans blue.The non-reflowed area after reperfusion was observed by thioflavin S staining.Results Mortality was the highest in the 90 min ischemia group.The numbers of ventricular fibrillations and defibrillations were increased significantly with increasing ischemia time(P<0.05,P<0.01).Ejection fraction and fractional shortening were obviously lower after 90 min of ischemia and ay 3 h of reperfusion compared with those in the other groups(P<0.05,P<0.01).No significant differences were found in the electrocardiogram,areas of myocardial infarction and non-reflow,myocardial tissue staining,or serum levels of CK-MB,LDH,SOD,and MDA among model groups.Conclusions A swine model of MI/RI with 90 min of ischemia had strong arrhythmias and high mortality,whereas models established under ischemia for 30 min with reperfusion for 3 h replicated the characteristic lesions of clinical disease with low mortality and are suitable for studies of pathogenesis and drug actions.