Exosomal miR-301 derived from mesenchymal stem cells protects myocardial infarction by inhibiting myocardial autophagy

Abstract Purpose To investigate the protective effects of miR-301 in exosomes secreted by bone mesenchymal stem cells (BMSCs) on rats' myocardial infarction (MI). Methods After isolation and culture, BMSCs were identified using flow cytometry. Then exosomes were then isolated. Rats MI models were established and they were divided into 4 groups: Sham group, Model group (injected with PBS), BMSC-Exos group (injected with exosomes secreted by BMSCs), BMSC-301-Exos group (injected with exosomes secreted by BMSCs transfected with miR-301 mimics). Cardiac function was assessed by cardiac echocardiography. Myocardial infarct area was measured by Masson trichrome staining mRNA and proteins expression were measured by qRT-PCR and western blot. Exosome morphology and myocardial cells autophagy were observed by transmission electron microscopy. Results BMSCs were obtained. Rat MI models were successfully established. After rats were injected with exosomes secreted by BMSCs transfected with miR-301 mimics, MI tissues were found to have much higher miR-301 expression, LVEF, LVFS, P62 expression, and remarkably lower LVESD, LVEDD, MI area, LC3-II/LC3-I ratio and autophagosomes numbers compared with BMSC-Exos group (all P Conclusion miR-301 in exosomes secreted by BMSCs protected MI by inhibiting myocardial autophagy.