家兔心脏短期缺血后再灌流时心功能的变化及SOD的影响

The changes of cardiac function during the shortly ischemic-reperfusion and the effect of superoxide dismutase

本实验利用家兔急性心肌缺血后早期再灌流动物模型,观察早期再灌流对心功能的影响,并利用自由基清除剂(超氧化物歧化酶,s0D)探索自由基在其中的可能作用。实验过程中测取心功能指标;观察结束后,分别从缺血区与非缺血区心内膜下取心肌电镜标本。实验发现,单纯再灌流组的心功能指标明显低于持续结扎组,SOD再灌流组的心功能比单纯再灌流组恢复得早、恢复程度高;缺血区心肌超微结构的损伤程度,依次为持续结扎组>单纯再灌流组>SOD再灌流组,非缺血区心肌超微结构只是单纯再灌流组变化较明显。结果表明,自由基对短期缺血后再灌流过程中心功能损伤起着一定的作用,其损伤范围随着再灌流的发生扩散到非缺血区。

This study was performed to assess the effect of myocardial ischemicreperfusion on cardiac function and research the action of free radicals in the reperfusion injury by observing the effect of free radical scavenger (superoxide dismutase, SOD) in the shortly ischemic-reperfused rabbits. Three groups were studied: Group Ⅰ (SOD 300u/kg, n= 10) and Group Ⅱ (control, n= 8) were subjected to 15 rain of total occlusion of the left ventricular branch of coronary artery (LVB) followed by 10 min of reperfusion; in Group Ⅲ (n= 8), rabbits underwent continuous occlusion of LVB for 25 min. Cardiac index (CI), left ventricutar systolic peak pressure (LVSP), maximum rate of left ventricular pressure development (+dp/dr max), and maximum rate of fall of left ventricular pressure (-dp/dr max) in the Group Ⅱ were significantly lower than those in the Group Ⅰ and Group Ⅲ during reperfusion. According to the Sunamori's method with which the myocardial ultrastructure can be analysed quantitatively, the most serious injury in the ischemic area was found in Group Ⅲ, then Group Ⅱ and Group Ⅰ; in the non-ischemic area, obvious injury was only found in Group Ⅱ. The results suggested that the cardiac function was obviously suppressed during reperfusion after short period of regional ischemia and that the oxygen free radicals might play an important role in this reperfusion injury. The features of myocardial ultrastructure indicated that ultrastructural damage implicated not only ischemic area but also non-ischemic area during reperfusion. was obviously suppressed during reperfusion after short period of regional ischemia and that the oxygen free radicals might play an important role in this reperfusion injury. The features of myocardial ultrastructure indicated that ultrastructural damage implicated not only ischemic area but also non-ischemic area during reperfusion.