Abstract

OBJECTIVE: The incidence of acute myocardial infarction (AMI) has increased significantly in recent years, seriously threatening human life and health. This paper focused on the role of microRNA-802-5p (miR-802-5p) in myocardial infarction (MI) and its underlying mechanisms.MATERIALS AND METHODS: Quantitative Real-Time Polymerase Chain Reaction (RT-PCR) was employed to detect miR-802-5p expression. Western blot was performed to detect protein expression. Flow cytometry and terminal dexynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) staining were performed to observe myocardial apoptosis. Hematoxylin-eosin (HE) staining was used to observe the morphology of myocardial tissue. The cardiac function of rats was detected using echocardiography.RESULTS: The expression of miR-802-5p was increased in hypoxic-treated H9c2 cells and infarcted myocardium in MI rats. Hypoxia treatment reduced the viability of cardiomyocytes and increased the level of lactate dehydrogenase (LDH) in the cell supernatant. Hypoxia treatment increased Bax expression in myocardial cells while Bcl-2 expression decreased, and the number of apoptotic cells increased. MiR-802-5p silencing reversed these effects. Moreover, miR-802-5p silencing reduced myocardial damage in MI rats, and significantly improved cardiac function. Through the Luciferase activity assay, we proved that miR-802-5p could directly target PTCH1. The knockdown of PTCH1 reversed the protective effect of miR-802-5p silencing on hypoxic myocardium.CONCLUSIONS: MiR-802-5p expression was increased in hypoxia-treated H9c2 cells and infarcted myocardium in MI rats. MiR-802-5p silencing could inhibit apoptosis after MI via activating Sonic Hedgehog signaling pathway by targeting PTCH1, thereby reducing myocardial injury and improving cardiac function of MI rats.