OBJECTIVE: Myocardial ischemia-reperfusion injury (IRI) is common in myocardial infarction and is the leading cause of death. Therefore, we investigated the effect of miR-486 on myocardial IRI to explore new targets for clinical treatment of IRI. MATERIALS AND METHODS: We made a rat myocardial IRI model by obstructing the coronary arteries and detected the change of miR-486 expression in rat myocardial tissue. In addition, we induced injury of rat cardiomyocytes (H9c2 cells) by hypoxia/reoxygenation and transfected H9c2 cells with agomir-miR-486 and antagomir-miR-486 to detect the effects of miR-486 on the viability, inflammation and apoptosis of cardiomyocytes. We also used the Targetscan system to predict the direct target of miR-486 and verified the effect of miR-486 on downstream targets through the Dual-Luciferase reporter assay. RESULTS: HE staining and the detection of myocardial injury markers and inflammatory factors verified the effectiveness of IRI rat model. The expression of miR-486 in myocardium of IRI rats was significantly lower than that of the control group. The overexpression of miR-486 in H9c2 cells increased the viability of H9c2 cells and reduced the levels of inflammation and apoptosis. MiR-486 is predicted to have a potential binding site to forkhead box D3 (FOXD3). The Dual-Luciferase reporter assay proved that miR-486 can bind and degrade FOXD3 mRNA. In addition, the overexpression of FOXD3 was found to attenuate the protective effect of miR-486 on H9c2 cells. CONCLUSIONS: MiR-486 protects cardiomyocytes and reduces the levels of inflammation and apoptosis by binding and inhibiting FOXD3 activity. Therefore, miR-486 may become a new target for myocardial IRI therapy.