MicroRNA-128 Regulates Myocardial Ischemia Reperfusion Injury Mainly By Targeting NRF2

Objective:Myocardial infarction is the leading cause of death in patients with coronary heart disease.At present,thrombolytic therapy or early intervention in the ischemic site,can effectively improve myocardial ischemia or necrosis.However,it still leads to the loss of some of the myocardial cells and the reduction of cardiac function,that is,ischemia reperfusion injury.MicroRNA?miRNA,miR?is a class of small non coding RNA molecules.Recent studies have shown that miRNA plays an important role in myocardial ischemia reperfusion injury.The transcription factor NF-E2 related factor 2?Nuclear factor erythroid2-related factor 2,Nrf2?-antioxidant response element?antioxidant response,element,ARE?is a kind of important endogenous antioxidant stress pathway.Enhanced expression of Nrf2 is demonstrated to effectively reduce the damage of myocardial cells and improve the cardiac function.Therefore,how to effectively regulate the Nrf2-ARE signaling pathway plays an important role in the prevention and treatment of oxidative stress related diseases.In this study,we mainly focused on the role of miR-128 in the prevention of myocardial ischemia reperfusion injury.By actively exploring the role and mechanism of miR-128 injury in myocardial ischemia reperfusion,it may provide new therapeutic strategies for the treatment of ischemic heart function and myocardial cell damage.Methods:1.We collected 40 patients with acute myocardial ischemia and 30 healthy controls,and collected the peripheral blood from the elbow vein.2.Meanwhile,the rat models of myocardial ischemia were established.The m RNA levels of miR-128 and Nrf2 were detected by immunohistochemistry and real-time quantitative PCR.3.Dual luciferase reporter assay was performed to determine whether Nrf2 is the target gene of miR-128.4.The adenovirus vectors expressing or silencing miR-128 were established and then transfected it into the myocardial tissue of rats.Myocardial tissue was collected to detect the level of ROS,apoptosis and the improvement of cardiac function?+dp/dtmax,LVSP,LVEDP?.Hoechst staining,flow cytometry and TUNEL staining were used to detect the apoptosis of myocardial cells in rats.5.Mitochondrial damage was observed by transmission electron microscope.Results:1.The expression level of miR-128 was increased in the patients with acute ischemic myocardium.2.The level of miR-128 increased in the model of ischemia reperfusion injury in rats and the level of Nrf2 decreased.3.In addition,H₂O₂ stimulation significantly increased the level of miR-128 in vitro.Bioinformatics analysis demonstrated a conserved binding site in the UTR '3' region of Nrf2.The results of dual luciferase reporter gene analysis showed that miR-128 could effectively inhibit the relative luciferase activity.4.In vivo studies showed that overexpression of miR-128 could effectively inhibit the expression of Nrf2,and the inhibition of miR-128 could increase the expression of Nrf2 in myocardial cells.The expression of HO1,NQO1 and SOD1 increased with the increase of the expression level of NRF2 in myocardial cells.The inhibition of miR-128 in rat myocardial tissue significantly increased the expression of antioxidant enzymes,while the level of ROS in myocardial tissue was significantly reduced.At the same time,inhibition of miR-128 can effectively reduce the apoptosis of myocardial cells and improve myocardial function after ischemia reperfusion injury.5.Transmission electron microscopy analysis showed that in the ischemia/reperfusion injury group,the mitochondria of the myocardial tissue were severely swollen,vacuolar,and the inner and outer membrane structures were not complete.On the contrary,after the inhibition of miR-128 in myocardial tissue,the swelling of mitochondria in myocardial cells was relieved.Conclusion:1.The expression level of miR-128 was increased in the patients with acute ischemic myocardium.2.The level of miR-128 increased in the model of ischemia reperfusion injury in rats. Mi R-128 regulates cell apoptosis by regulating Nrf2.3.The expression of miR-128 in myocardial ischemia-reperfusion injury model increased.By inhibiting the miR-128 affect the level of ROS to reduce the number of apoptotic cells in myocardial tissue,thus affecting myocardial injury.