ARC Expression On Myocardial Protection Of ATP-Postconditioning In Isolated Rat Hearts

Objective To investigate ARC expression on myocardial protection of ATP-postconditioning in isolated rat hearts.Metheds Thirty-two Wistar rats were randomly divided into four groups(n=8):control group(Con group),ischemia reperfusion group(I/R group),ATP-postconditioning group(ATP-Post group) and antisense oligonucleotide administration+ATP-postconditioning group(AS+Post group).Con group:rats were anaesthetized with heart explosion,and then The left ventricular samples of the rats through thoracotomy under anaesthesia were collected.I/R group:Langendorff and Neely perfusion models were steadily established for 30min,then the rats hearts were arrested by cardioplegia St.Thomas No.2 solution(STH-2),these arrested hearts were remainded for 30min and then underwent reperfusion for 60min. ATP-Post group:At the start of reperfusion,the rat hearts were perfused ATP (4mg/kg) under the same procedure as Group I/R,and then the left ventricular samples were collected.AS+Post group:Each rat was administered intravenously 5μmol/L of antisense oligonucleotide,other procedure as Group ATP-Post.The content change of myocardial ARC and cytosolic cytochrome C were detected by Western Blot(WB),and the apoptosis index(AI) of cardiocyte was detected by TUNEL.Results The ARC expressions detected by WB were 243.11±8.57% in group Con, 76.26±2.71% in group I/R, 218.59±7.43% in group ATP-Post and 42.52±1.90% in group AS+Post.The cytosolic Cyt-C expressions detected by WB were 1.30±0.11% in group Con, 46.67±3.92% in group I/R, 28.73±2.46% in group ATP-Post and 45.52±3.83% in group AS+Post. The expressions of ARC in I/R group,ATP-Post group and AS+Post group were decreased significantly compared with Con group(P<0.05);the content of ARC in ATP-Post group was higher significantly than those in I/R group and AS+Post group(P<0.05).The expressions of cytosolic Cyt-C in I/R group,ATP-Post group and AS+Post group were increased significantly compared with Con group(P<0.05);the content of cytosolic Cyt-C in ATP-Post group was lower significantly than those in I/R group and AS+Post group (P<0.05).The expression of ARC had a negative correlation with the expression of cytosolic Cyt-c (r=﹣0.768,P<0.05).AI in Group I/R(18.46±1.55%),Group ATP-Post (6.78±(6.78±0.57%) and Group AS+Post(16.78±1.41%) was higher than that (4.88±0.41%) in Group Control(P<0.05);AI in Group ATP-Post was lower than that in Group I/R(P<0.05);treated with AS, AI in Group AS+Post was higher than that in Group ATP-Post(P<0.05).The expression of ARC had a negative correlation with the change of AI(r=﹣0.908,P<0.05).Conclusion It was suggested that ARC played an important role in myocardial protection of ATP-postconditioning in rat hearts.The possible mechanism could be that ARC expression increased after ATP-postcongditioning,and it let to alleviate myocardial ischemia/ reperfusion injury by inhibiting of cytochrome c release and reducing apoptotic cardiomyocytes.