| Objective : The effect of exosomes on AMI repair has been demonstrated in many researches. However,the mechanism of microRNA in AMI repair is still uncertain.The purpose of this study is to investigate the mechanism of microRNA in exosomes repair of myocardial infarction, and provide new therapeutic targets for the treatment of acute myocardial infarction.Methods : Exosomes were separated and purified through ultrafiltration and density gradient ultracentrifugation,and identified by nanoparticle tracking analysis.AMI models of SD rat were accomplished successfully by ligating the left anterior descending(LAD) of coronary artery in vivo;In vitro,cardiomyocytes were cultured with no oxygen to gain hypoxia model,and determined by echocardiograph and western blot.On the basis of constructing successfully the exosomes-repaired model of cardiac hypoxia in vivo and in vitro,the levels of relavant microRNAs were determined by fluorescence quantitative PCR.Targets were predicted via bioinformatics.Afer miR-92 b mimics and inhibitor were transfected into cardiomyocytes,Smad7 mRNA and protein were tested to investigate the possible mechanism of microRNA in exosomes-mediated repair effect of AMI.Results: Exosomes were separated successfully.The hypoxia-induced model of cardiomyocytes in vivo and in vitro were accomplished and passed the test of echocardiograph and western blot.The leve of mi R-92 b in exosomes is very high determined by fluorescence quantitative PCR;Meanwhile,serum level of mi R-92 b of AMI rat model is also high.Protein and mRNA of Smad7 in exosomestreated and miR-92 b mimics transfected cardiomyocytes are upregulated together.Conclusion: In the process of exosomes repairing AMI,exosomes filled with mi R-92 b is possible to upregulated Smad7,then improve cardiac function. |
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