Study On The Role Of Integrin ?3 In Hypoxia Induced Cardiomyocyte Apoptosis

Background: Apoptosis plays a very important role in the development of ischemic heart disease.Cardiomyocyte apoptosis is an important factor leading to heart failure and prognosis after myocardial infarction.Integrin ?3 plays an essential role in bidirectional regulation of cardiomyocyte proliferation and apoptosis,but its role in hypoxia-induced cardiomyocyte apoptosis is still unclear which needs to be further clarified.In this study,we provide a new and effective target for the future intervention of myocardial cell apoptosis by exploring the role of integrin?3 in cardiomyocyte apoptosis induced by hypoxia.Methods: H9C2 cardiomyocytes and rat primary cardiomyocytes were treated with cobalt chloride(Co Cl2)or hypoxia incubator(1% O2)to simulate the hypoxic environment of cardiomyocytes.Western blot and real-time PCR were used to detect the changes of integrin ?3 protein and m RNA expression in cardiomyocytes.TUNEL method and Annexin V flow cytometry were used to detect cardiomyocyte apoptosis.Rat models of acute myocardial infarction(AMI)were ligated by ligation of the coronary arteries and the expression of integrin ?3 and HIF1? in myocardial tissue was detected by immunohistochemistry.Results: We induced H9C2 cells hypoxic microenvironment by using Co Cl2 or hypoxia culture(1% O2).Hypoxia can inhibit the proliferation of H9C2 cells in a time-and dose-dependent manner.Alos the H9C2 cardiomyocyte apoptosis can be induced by hypoxia.The expression of integrin ?3 and HIF1-? were upregulated in H9C2 cardiomyocytes under hypoxic conditions.Interference with integrin ?3 expression could induce cardiomyocyte apoptosis,which promoted hypoxia-induced cardiomyocyte apoptosis.However,the overexpression of integrin ?3 in H9C2 cells could downregulated cardiomyocyte apoptosis.Myocardial apoptosis was significantly increased in myocardial tissue of AMI rats.Compared with the control rats,the expression of integrin ?3 and HIF1? protein in AMI rat heart tissue were significantly increased.Conclusion: Hypoxic microenvironment inhibits cardiomyocyte proliferation and induces apoptosis.Integrin ?3 inhibits hypoxia-induced cardiomyocytes apoptosis both in H9C2 cardiomyocytes and AMI rat heart tissues.Integrin ?3 plays a protective role in hypoxia-induced cardiomyocyte apoptosis.