Study On Effect Of MiR-497-5p Mediated By Mesenchymal Stem Cell-derived Exosomes On Apoptosis Of Myocardial Infarction Cells

Objective:This study aimed to detect the effects of miR-497-5p mediated by exosomes of bone marrow mesenchymal stem cells(BMSC)on apoptotic factors of rat cardiomyocytes were detected by constructing cardiomyocyte hypoxia and reoxygenation model,so as to explore the internal relationship between BMSCs and myocardial apoptosisbone marrow mesenchymal stem cell.Methods:1.Primary bone marrow mesenchymal stem cells were extracted from rats for isolation and culture.2.The miR-497-5p mimic and mimic NC were transfected into BMSC respectively,and then exosomes were extracted from the BMSC culture medium.3.The experiment was conducted with H9C2 cells and divided into five groups:(1)Cardiomyocytes were cultured normally;(2)Myocardial cell injury modeling(OGD/R);(3)Cardiomyocytes were co-cultured with exosomes of normal BMSCs and then hypoxic and reoxygenated;(4)Cardiomyocytes were co-cultured with exosomes which transfected with NC mimic,and then treated with hypoxia and reoxygenation;(5)Cardiomyocytes were co-cultured with exosomes which transfected with miR-497-5p,and then subjected to hypoxia and reoxygenation treatment.4.The apoptosis rate of each group was detected by flow cytometry,and the protein expression levels of Bax,Bcl-2,NF2 and PAK1 in cells were detected by WB.Results:1.The apoptosis rate of H9C2 cells in the myocardial injury model group was higher than that in the normal culture group.2.Compared with the cardiomyocyte hypoxia model group,there was no significant difference in the apoptosis rate of normal BMSC treated with exosomes,while the apoptosis rate of OGD/R cells in the BMSC transfected with NC mimic and miR-497-5p mimic increased.3.The apoptosis rate of H9C2 cells in the exosome group transfected with miR-497-5p mimic was higher than that in the exosome group transfected with mimic NC.4.WB test results showed that compared with the myocardial injury model group,the expressions of Bax,Bcl-2,Nf2 and PAK1 in cells of other groups were significantly decreased except for the normal culture group,with statistical significance(P < 0.05).In addition,compared with the OGD/R cells treated with mimic NC exosomes,the expression of Bcl-2,NF2 and PAK1 in OGD/R cells transfected with miR-497-5p exosomes decreased significantly(P < 0.05).Conclusion:The exosomes of BMSC transfected with miR-497-5p could inhibit the expression of NF2 and PAK1 proteins and promote the apoptosis of H9C2 cells after co-culture with cardiomyocytes.