The Effect Of Adenosine Postconditioning On HSP70and Cardiomyocyte Apoptosis After Myocardial Ischemia-reperfusion Injury In Rats

Objective:The purpose of the article explores protective effect of adenosine(AD) postcon-ditioning on ischemia-reperfusion injury which induces reperfusion arrhythmia, levels changes of LDH and CK in Serum, pathological appearance changes, cardiomyocyte apoptosis and expression of HSP70protein on myocardial ischemia-reperfusion injury rats models,and studies possible mechanism of adenosine postconditioning in ischemia-reperfusion(I/R) and provides a theoretical evidence for clinical application.Methods:I/R model in vivo rats were established(deligating left anterior descending).24healthy male wistar rats were divided randomly into:Sham operation group (Sham)(n=8): don’t deligate the blood vessel;Ischemia-reperfusion group(I/R)(n=8):left anterior descending (LAD) occlusion for30min and reperfusion for120min;Adenosine postconditioning group (AD)(n=8):left anterior descending(LAD) occlusion for30min and reperfusion for120min,the group was given adenosine305μg/kg·min for5min through femoral vein before reperfusion. Reperfusion arrhythmia was observed for30min at the beginning of reperfusion; The levels of LDH and CK in Serum were determined; HE stain method was used to observe cardiomyocyte pathomorphology appearance by light microscope;TUNEL method was used to measure the rate of cardiomyocyte apoptosis of each group; Immunohistochemical SABC technique was used to measure the expression of HSP70.Result:①Reperfusion arrhythmia:within30minutes of reperfusion:Compared with the sham group, the rate of VT、 VF and arrhythmia score were considerably increased in I/R group (P<0.05),and compared with I/R group,they were considerably decreased in AD group (P<0.05).②The levels of LDH (U/L)and CK(U/mL) in Serum:The levels of LDH and CK were considerably increased in I/R group(13293.14±1366.99;107.18±8.77),and compared with I/R group,they were considerably decreased in AD group(7632.65±594.85;84.81±9.05)(P<0.05).③Pathological changes of myocardial tissue:the degree of myocardial damage of AD group is much litter than that of I/R group.④Cardiomyocyte apoptosis rate(%):the I/R group (38.533±2.056)has a higher rate of cardiomyocyte apoptosis than that of the sham group (0.703±0.056)(P<0.05);Compared with the I/R group,AD group(26.375±2.073) has a consi-derably lower rate of cardiomyocyte apoptosis(P<0.05).⑤The results of HSP70expression by immunohistochemical SABC technique(mean optical density value):Compared with sham group (0.185±0.019),HSP70expression level in I/R group(0.222±0.014)was considerably increased (p<0.05);Compared with I/R group,HSP70expression level in AD group(0.243±0.022)was much higher(p<0.05).Conclusion:Adenosine postconditioning can reduce myocardial ischemical reperfusion injury and protect myocardial tissue. Adenosine postconditioning can increase the expression of HSP70and inhibit cardiomyocytes apoptosis, and then protect cardiomyocytes from ischemical reperfusion injury.