Diosmetin alleviates hypoxia-induced myocardial apoptosis by inducing autophagy through AMPK activation

Diosmetin has shown great potential in the control of several diseases. The aim of the present study was to evaluate the role of diosmetin as a candidate agent for the treatment of myocardial infarction which was mainly caused by hypoxia. The model of hypoxia-injured myocardial cells was established using the H9c2 cell line. Cell viability was determined using Cell Counting Kit-8, cell apoptosis was determined by Annexin V-FITC Apoptosis Detection Kit and cleaved caspase-3 level was assessed by western blot analysis. Autophagy was monitored using a commercial kit, and a well-established reporter system was used to confirm the role of diosmetin in autophagy. The activity of adenosine 5′-monophosphate-activated protein kinase (AMPK) signaling was detected by western blot analysis. Cell viability assay indicated that diosmetin alleviated hypoxia-induced cell death of H9c2 cells in a dose-dependent manner. Data of the apoptosis assay revealed that diosmetin reduced the proportion of apoptotic cells in the hypoxia-injured H9c2 cells. It was also found that the occurrence of autophagy was promoted when hypoxia-injured cells were treated with diosmetin alone, and results of the western blot analysis revealed that AMPK signaling was activated by diosmetin. Administration of diosmetin together with an inhibitor of autophagy (3-methyladenine, 3-MA) or AMPK (Compound C) was able to decrease the diosmetin-induced autophagy as well as the cytoprotective effects in the hypoxia-injured cells. Our study concluded that diosmetin exhibits a cytoprotective effect on hypoxia-injured myocardial cells by inducing autophagy and alleviating apoptosis. AMPK was demonstrated to regulate the observed effects caused by diosmetin. This investigation confirmed diosmetin as a promising drug candidate for myocardial infarction treatment. The present findings regarding the inherent molecular mechanisms involved in the protective effects of diosmetin promote the clinical application of diosmetin.