Objective To investigate the role and mechanism of miR-494 in doxorubicin(DOX)induced cardiomyocyteinjury in rats.Methods H9C2 cells were divided into four groups:control group,DOX group,DOX+negative control(NC)mimics group,and DOX+miR-494 mimics group.Except for the control group,the remaining three groups wereexposed to 5 μmol/L DOX to establish a cardiomyocyte injury model,the latter two groups were transfected with NC mimics and miR-494 mimics,respectively.Cell viability was detected using the cell counting kit-8.Quantitative real-time polymerase chain reaction was used to detect the mRNA expression levels of miR-494,phosphatase and tensin homolog(PTEN).Terminal-deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling was used to detect cell apoptosis rate.Western blot was used to detect the expression levels of B-cell lymphoma-2(Bcl-2),Bcl-2 associated X protein(Bax),PTEN,phosphorylated PI3K(p-PI3K),and phosphorylated Akt(p-Akt).Enzyme-linked immunosorbent assay was used to detect the levels of lactate dehydrogenase(LDH)and creatine kinase-MB(CK-MB).Verify the interaction between miR-494 and PTEN using dual-luciferase reporter assay.Results Compared with the control group,the apoptosis rate,Bax protein expression level,LDH and CK-MB content of H9C2 cells in the DOX group were significantly increased(all P＜0.01),while cell viability and Bcl-2 protein expression level were significantly reduced(all P＜0.01).Compared with the DOX+NC mimetic group,the apoptosis rate,Bax protein expression level,LDH and CK-MB content of H9C2 cells in the DOX+miR-494 mimetic group were significantly reduced(all P＜0.01),while cell viability and Bcl-2 protein expression level were significantly increased(all P＜0.01).PTEN has binding sites with miR-494.The luciferase activity of PTEN-WT was significantly reduced by the miR-494 mimetic(P=0.010),while the luciferase activity of PTEN-MUT was not affected by the miR-494 mimetic(P=0.707).Compared with the control group,the expression levels of p-PI3K and p-Akt proteins in H9C2 cells in the DOX group were significantly reduced(all P＜0.01).Compared with the DOX+NC mimetic group,the expression levels of p-PI3K and p-Akt proteins in H9C2 cells in the DOX+miR-494 mimetic group were significantly increased(all P＜0.01).Conclusion miR-494 may regulate the PI3K/Akt signaling pathway by targeting and inhibiting PTEN expression,thus ameliorating DOX induced cardiomyocyte injury.
DoxorubicinmiRNA-494CardiomyocytesPhosphatase and tensin homologPhosphatidylinositol 3-kinase/protein kinase B signal pathway
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