大鼠心肌缺血再灌注后心肌梗死面积和无复流面积的动态变化及其相关性的初步研究

Dynamic Changes of Myocardial Infarction Area and Non-reflow Area and Their Correlation in Rats Suffering from Myocardial Ischemia and Reperfusion

目的研究大鼠心肌缺血再灌注后无复流现象中心肌梗死面积和无复流面积的动态变化及其相关性。方法采用健康雄性Wistar大鼠,分两批进行实验。第1批实验,固定再灌注时间为2 h,将大鼠随机分为4组:①缺血2 h组,②缺血3 h组,③缺血4 h组,④假手术组。第2批实验,固定缺血时间为4 h,大鼠随机分为6组:①再灌注2 h组,②再灌注4 h组,③再灌注8 h组,④再灌注24 h组,⑤再灌注3 d组,⑥假手术组。缺血再灌注组结扎冠状动脉左前降支一定时间后再灌注,假手术组只穿线不结扎。分别用硫磺素S和硝基四氮唑蓝(N-BT)染色评估心肌无复流面积和梗死面积。结果所有缺血再灌注组均出现明显的心肌无复流现象。心肌梗死面积和无复流面积随缺血时间的延长而扩大,缺血2 h,即可见明显的心肌无复流现象,无复流区与血液灌注区界限明确;缺血3 h,可见明显心肌梗死,但界限不清;缺血4 h梗死区与未梗死区界限清晰。再灌注8 h内,心肌梗死面积和无复流面积随再灌注时间的延长明显扩大、延展,无复流面积略大于梗死面积;再灌注8 h后,心肌梗死的扩展速度进入平台期,而无复流面积则呈逐渐减少趋势;再灌注3 d后,心肌梗死和无复流区域基本重合,二者面积趋于一致。结论在本研究选定的缺血时间和再灌注时间的条件下,心肌缺血再灌注模型大鼠的心肌无复流发生率是100%,可作为心肌无复流模型使用。心肌梗死面积和无复流面积随缺血时间和再灌注时间的延长而扩大,并均在再灌注8 h达峰值;此后梗死面积基本固定,而无复流现象出现部分恢复和改善。

Objective To investigate the dynamic changes of myocardial infarction area and non-reflow area and their correlation in rats suffering from myocardial isehemia and reperfusion. Methods Healthy male Wistar rats were used for 2 independent experiments. In the first experiment, 2-hour reperfusion was fixed, and rats were randomly divided into 4 groups, namely 2-hour myocardial ischemia group, 3-hour myocardial ischemia group, 4-hour myocardial ischemia group, and sham operation group. In the second experiment, 4-hour ischemia was fixed, and rats were randomly divided into 6 groups, namely 2-hour repedusion group, 4-hour reperfusion group, 8-hour tperfusion group, 24-hour reperfusion group, 3-day reperfusion group, and sham operation group. Myocardial ischemia was induced byligation of left anterior descending coronary artery, and the rats were subjected to ischemia for a certain time followed by reperfusion. The rats in the sham operation group did not undergo occlusion of the coronary artery. The myocardial non-reflow area and infarction area were assessed by thioflavin S and nitrotetrazolium blue chloride, respectively. Results All the ischemia/reperfusion groups showed significant myocardial non-reflow phenomenon. The myocardial infarction area and no-reflow area extended with ischemic duration. After ischemia for 2 hours, myocardial non-reflow phenomenon was obvious, and the boundary between non-reflow area and blood perfusion area was clear. After ischemia for 3 hours, myocardial infarction was obvious, but the boundary was not clear, and the limit became clear until ischemia lasted for 8 hours. During the reperfusion for 8 hours, myocardial infarction area and non-reflow area extended with the prolongation of reperfusion, and the non-reflow area was slightly larger than the infarction area. After reperfusion for $ hours, infarct expansion sped into the platform, and non- reflow area gradually reduced. And after reperfusion for 3 days, myocardial infarction area and non-reflow area basically overlapped, and the two areas almost became the same. Conclusion After appropriate ischemia time and reperfusion time, the occurrence rate of no reflow is 100 % in myocardial ischemia/reperfusion rat model, and the model can be used as myocardial non-reflow model. The myocardial infarction area and non-reflow area extend with the prolongation of ischemia/reperfusion time, and reach the peak after reperfusion for 8 hours. And then, the infarction area basically becomes steady, and non-reflow area is reduced and improved partly.