The Profective Effect Of Long Non-coding RNA-DQ402472 ShRNA Interference On High Fat-Diet Induced Myocardial Ischaemia/Reperfusion Injury

Background and ObjectiveMyocardial infarction is a type of acute myocardial ischemic necrosis with high disabling mortality caused by acute coronary occlusion.Recovering coronary blood flow as soon as possible is the most important method to reduce the area of myocardial infarction and improve cardiac function and reduce mortality.However,myocardial damage induced by reperfusion itself,namely myocardial ischemiareperfusion injury(IRI),is a bottleneck that restricts the efficacy of coronary heart disease.Excessive intake of dietary fat can cause many health problems such as obesity,hypercholesterolemia and cardiovascular diseases,and it is an important risk factor for myocardial IRI vulnerability.Dietary high fat may cause cardiomyocyte apoptosis and cardiac function damage and increase the susceptibility of the myocardium to IR injury,thereby aggravating ischemic heart disease.In recent years,with the rapid development of ln RNA researches,it has been found that lnc RNA is involved in many disease processes including cardiovascular diseases.Numerous studies have shown that lnc RNA can regulate apoptosis and affect the occurrence and development of diseases.We aimed to explore the role of DQ402472,a long noncoding RNA found to be associated with myocardial IRI vulnerability to high-fat diet based on our previous study on lnc RNA chip,in high fat-diet induced myocardial IRI.It may provide the clues and new targets for prevention and treatment of myocardial IRI in response to high-fat diet.Methods1)8 weeks,12 weeks and 16 weeks of high-fat diet rat models were established.Ligation and restoration of blood flow in the left anterior descending coronary artery were performed to establish a high-fat diet myocardial IRI animal model.Hemodynamic parameters,myocardial infarct size,serum myocardial enzyme CK and LDH activity,and apoptosis were assessed to assess cardiac function and myocardial injury.Western blot was used to detect GSK-3β and its phosphorylation and cytoplasmic cytochrome C in IRI myocardium.The expression of lnc RNADQ402472 in IRI myocardium was analyzed by Real-time PCR.The role of DQ402472 in myocardial IRI vulnerability to high-fat diet was thus investigated.2)The DQ402472 sh RNA plasmid was transfected in IRI m of high-fat dietary rats.Hemodynamic parameters,myocardial infarct size,serum myocardial enzyme CK and LDH activity,and apoptosis were assessed to study the impairment of cardiac function and myocardial injury.Western blotting was performed to analyze the levels of GSK-3β and its phosphorylation and cytoplasmic cytochrome C in IRI myocardium.Real-time PCR was used to DQ402472 to investigate the effect of DQ402472 expression in IRI myocardium.In situ hybridization(ISH)was used to detect the subcellular localization of DQ402472.Bioinformatics analysis was applied to analyze the interaction between DQ402472 and GSK-3β protein.The role of DQ402472 sh RNA was thus studied in high fat-diet induced myocardial IRI.Results1)8 weeks,12 weeks and 16 weeks high-fat diet time-dependently induced the increase of myocardial infarct size and serum CK and LDH activity,impaired left ventricular function,increased myocardial cell apoptosis and caspase 3 activity;Meanwhile,high-fat diet time-dependently induced the expression of DQ402472 and decreased the phosphorylation of GSK-3β in IRI myocardium(all p < 0.05).2)DQ402472-sh RNA interference inhibited high-fat diet induced DQ402472 expression in IRI myocardium.DQ402472-sh RNA interference suppressed the increment of myocardial infarction area and serum CK and LDH activity,enhanced the impaired left ventricular function and GSK-3β phosphorylation level,attenuated the increased caspase 3 activity and myocardial apoptosis induced by high-fat diet(all p < 0.05).The results of in situ hybridization(ISH)suggested that DQ402472 was expressed in myocardial cytoplasm.Bioinformatics analysis showed that DQ402472 may interact with 250-400 amino acids of GSK-3β protein.Conclusion:DQ402472 sh RNA inhibits the decrease level of GSK-3β phosphorylation and the increment of cell apoptosis in IRI myocardium caused by long-term high-fat diet,which protects IRI myocardium from high-fat diet.