Effects of microRNA-139 on myocardial cell injury induced by oxidative stress.

Objective: This study aims to explore the effects of miR-139 on myocardial cell injury induced by oxidative stress and its mechanisms. Methods: H9c2 cells were used in this study. They were divided into control group, H2O2 group, H2O2+miR-139-5-p NC group and H2O2+miR-139-5-p mimics group. Cell activity was detected by MTT method. ROS level was detected by DCFH-DA probe method. MDA and SOD levels and Caspase 3 activity were detected by spectrophotometry. The cell apoptosis was detected by Hoechst 33342 and Annexin V-FITC/PI staining methods. The expression levels of AKT, GSK-3β, Bax and Bcl-2 were determined by Western blotting methods. Results: It showed that the activity of H9c2 cells decreased with the increase of the dose of H2O2. The activity of miR-139-5-p in H9c2 cells decreased after treatment of H2O2 for 6 h (P<0.01). Compared with control group, cell activity in H2O2 group and H2O2+miR-139-5-p NC group decreased (P<0.01), ROS fluorescence intensity increased (P<0.01), MDA content increased (P<0.01), SOD content decreased (P<0.01), apoptosis degree, Caspase 3 activity and Bax levels increased (P<0.01), Bcl-2, AKT and GSK-3β decreased (P<0.01). However, they were opposite in H2O2+miR-139-5-p mimics compared with H2O2 group and H2O2+miR-139-5-p NC group. Conclusions: miR-139-5-p expressed low in oxidative stress of H9c2 cells induced by H2O2 and the oxidative stress injury could be inhibited after increasing the expression of miR-139-5-p, which could be related with the elimination of intracellular oxidative stress products and the resistance to apoptosis through AKT/GSK-3β signaling pathway.