Experiment Study Of Protective Effect Of Ischemic Precondition, Ischemic Postconditioning On Myocardial Reperfusion Injury Of Rabbit Living Body

Objective: To evaluate the cardioprotective effects offered by theischemic precondition and ischemic postconditioning and their superposition induced on rabbit's living body, discussing their mechanism by comparing biochemical indicator and ECG.Method thirty two rabbits randomly divided into fourgroups ( n=8 in each group). In anesthetized open-chest rabbits, the left anterior descending artery (LAD)was occluded for 30 minutes and reperfused for 3 hours. In controls(n=8), there was no intervention. In Pre-con(n=8), the LAD was occluded for 5 min and reperfused for 5 min (three cycles ) before the prolonged occlusion. In Post-con(n=8),at the start of reperfusion, three cycles of 30-s reperfusion and 30-s LAD reocclusion preceded the 3 hours of reperfusion. In superposition (n=8), 5 min and reperfused for 5 min (three cycles ),then preceded the 30min occlusion ,at the start of reperfusion, three cycles of 30-s reperfusion and 30-s LAD reocclusion,Results the comparing of vital sign in each groups is nodistinction(P<0.05); The levels of CK in the Pre-con,Post-con and superposition groups were significantly less than controls on the three points(P<0.05), The levels of CK in superposition group was significantly less than Pre-con,Post-con and control groups on the post three points(P<0.05). MDA was significantly lower at 3 hour of reperfusion versus controls in superposition group,Pre-con,Post-con (P<0.05).,superposition group was significantly less than Pre-con,Post-con and control groups(P<0.05);. The levels of SOD and ATP in the Pre-con,Post-con and superposition groups were significantly highter than controls(P<0.05), The levels of SOD and ATP in superposition group was significantly highter than Pre-con,Post-con,control (P<0.05) . ECG: raised extent of ST in V3 lead of the Pre-con,Post-con and superposition groups were significantly less than control (P<0.05);nodifference in Pre-con,Post-con,superposition groups on post three points (P>0. 05).Conclusion These data suggest that the superposition group ismore effective than Pre-con or Post-con.on myocardial reperfusion injury; energy metabolism of cadiocyte is associated with cell damage, this is ought to be a direction to study the mechanisms of Pre-con and Post-con.