Experimental Study Of Cardioprotection Of Remote Ischemic Postconditioning On Ischemia/reperfusion Injury In Insulin Resistant Rabbits

Objective:To observe the effect of cadioprotection of remote ischemic postconditioning with leg as a target organ on sulin resisitant rabbits.Metholds:Forty adult male rabbits, weight(1.3-1.5kg), had been fed 4 weeks with high sugger and oil fodder, in order to built up insulin resistant model. Then these rabbits were divided into four groups(each=10):①group sham(group sham):rabbits were underwent surgical procedures and passed the suture under the left anterior descending branch(LAD)but not tightened it;② ischemia/reperfusion group( group I/R): ischemia 45 min followed by reperfusion 3h;③remote ischemic postconditioning group(group RIP):the rabbits’ left arterial cruralis was occlusion 25 min and followed by 5 min reperfusion while LAD was ischemic 30 min and then reperfused 180 min;④ remote ischemic postconditioning and dimethyloxalylglycine(DMOG)group(group RIP+D): rabbits were injected with a 20mg/kg DMOG 24 hours before RIP,then we gave the same treatment as group RIP to them.Bloods were harvested from the right internal jugular vein at two time points(before ischemic and at the end of operation) respectively to analysis the concentration of creatine kinase(CK). Heart samples were collected to detect the myocardial infarct sizes by TTC method and also to detect the expression of HIF-1αby Western-blot method.Results:The levers of plasma concentration of glucose and insulin after feed are higher than the concentration before feed. So the insulin resistant index after feed is higher than that before feed.There are not significant differences in CK concentration of four groups beforeischemia(P>0.05). At the end of repufusion 180 min, in addition to the group sham,the concentrations of CK in the remaining three groups are higher than before ischemia. The CK concentration of group I/R was higher than it of group sham(P<0.01). The concentration of CK in group RIP was lower than it of group I/R(P<0.01). The CK concentration of group RIP+D was lower than it of group RIP(P<0.01).The myocardial infarct size of group sham is significantly smaller than group I/R(P<0.01).and the myocardial infarct size of group RIP+D is smaller than group I/R and group RIP(P<0.01). The myocardial infarct size of group RIP is smaller than group I/R(P<0.01).The expression of HIF-1α protein in group sham was lowest than other three groups. The expression of HIF-1α protein in group I/R was higher than it in group sham(P<0.05), and the expression of HIF-1α protein in group RIP was high than it in group I/R(P<0.05). The expression of HIF-1α protein in group RIP+D was higher than it in group RIP(P<0.05).Conclusions:1. Remote ischemic postconditioning reduced the myocardial ischemia reperfusion injury in insulin resistant rabbits.2. This cardiopretection of remote postcondition may be related to the upregulation of HIF.