Abstract: ObjectiveTo investigate the changes of expression of intercellular adhesion molecule 1 (ICAM-1) on myocardial ischemic reperfusion injury(IRI) in old rats and the cardiac protective effect of Esmolol(ES). Methods116 rats were divided into three groups: IR group, IR+ES group and Sham group. The ischemic samples were observed in ischemia and 3,6,12,24 hours after IR. The myocardial levels of expression of ICAM-1 mRNA were evaluated by method of IN Situ Hybridization and the protein were evaluated by immunocytochemistry. The content of infiltration of polymorphonuclear neutrophils(PMNs), malomdialdehyde(MDA), superoxides dismutase(SOD) and the myocardial infarction area were measured too. ResultsAfter IR, myocardial levels of expression of ICAM-1 mRNA, protein,MDA and PMNs were increased significantly; SOD was decreased significantly. Between the levels of expression of ICAM-1 protein and PMNs, infarction area of myocardium, a close correlation were observed(P<0.05). In IR+ES group, all of the indicators were increased after IR, but the levels of increase in IR+ES group were more significantly modification as compared with IR group(P<0.05-0.01).Conclusions The findings indicate that PMNs could induce myocardial IRI after IR, which result from the ICAM-1 mediated PMNs adhesion.ES is able to decrease myocardial IRI by blocking the expression of ICAM-1 partially.

Key words: cell adhesion molecules, myocardial ischemia, reperfusion injury, Esmolol