Vildagliptin Improve Autophagy To Alleviate Diabetic Cardiomyopathy Through The MiR-21a-5p/PTEN/Akt/mTOR Pathway

Objective:Diabetic cardiomyopathy?DCM?is a specific cardiomyopathy independent of hypertension,coronary heart disease and other diseases,and is closely related to the high incidence and high mortality of heart failure in patients with diabetes?Diabetes Mellitus,DM?.At present,DCM lacks specific diagnosis and treatment methods.Vildagliptin belongs to the class of dipeptidyl Peptidase IV?DPP4?inhibitors,whether this drug has a role in diabetic cardiomyopathy and its mechanism of action has not been elucidated.In this study,STZ/HFD-induced C57BL/6J mice,miR-21^-/-mice,and rat cardiomyocyte cell line?H9C2?were used as research objects,through in vivo experiments and cell experiments to explore:1.The effect and safety of vildagliptin on STZ/HFD-induced diabetic cardiomyopathy in C57 mice;2.microRNA-21 improves the role of autophagy in diabetic myocardium;3.The pathway of Vildagliptin prevents diabetic cardiomyopathy by acting miR-21.Methods:1.In vivo:C57/BL6J mice and miR-21^-/-mice were raised.C57 mice were randomly divided into normal control group?NC?,diabetic group?DM?,and vildagliptin intervention group?DM+Vild?,intervened with vildagliptin and injected the miR-21 adeno-associated virus group?DM+AVV9+Vild?,and vildagliptin with the no-load virus group?DM+AAV9 NC+Vild?group.MiR-21^-/-mice were randomly divided into miR-21^-/-NC group and miR-21^-/-DM group.After 10 weeks of vildagliptin intervention,the cardiac function of mice was detected by echocardiography.HE staining and Masson staining were performed to analyze the histopathological changes of heart tissue;immunohistochemical staining and Western Blot were used to analyze the changes of electrophysiological factors,autophagy marker protein and related regulatory factor proteins in diabetic hearts.2.In vitro:H9C2 was divided into normal glucose concentration group?5.5mM?,25 mM group,33 mM group and osmotic pressure control group were cultured for 24 h,48 h,and 72 h,respectively.And the expression of miR-21 was detected by qRT-PCR.The expression of PTEN/AKT/mTOR protein was analyzed by Western Blot;the cells were transfected with miR-21 Mimics and Inhibitors to detect the possible role of miR-21.Results:The effect of vildagliptin on diabetic cardiomyopathy in the STZ/HFD-induced diabetes mice;1.The fasting and random blood glucose levels in the DM group were significantly higher than those in the NC group?P<0.05?.The cardiac function of the DM group was significantly lower than that of the NC group.2.Vildagliptin can reduce the blood glucose level of diabetic mice?P<0.05?.And the echocardiographic results showed that the cardiac function was restored in DM+Vild group.MicroRNA-21 knockout improves the autophagy level in diabetic myocardium;1.The random blood glucose of mice in miR-21^-/-NC group was lower than that in C57 NC group?P<0.05?.The fasting and random blood glucose of mice in miR-21^-/-DM group were lower than those in C57 DM group?P<0.05?.Echocardiography showed that the cardiac function of mice in miR-21^-/-DM group was better than that in C57 DM group?P<0.05?.4.Immunohistochemistry and Western Blot showed that the expression of cx43in the miR-21^-/-DM group was higher than that in the C57 DM group,P62 was decreased,and LC3 expression was increased?P<0.05?.The mechanism of vildagliptin acting on miR-21 to alleviate diabetic cardiomyopathy1.After transfection of miR-21 mimics into H9C2 cells,the results of Western Blot showed that PTEN expression was decreased and p-AKT and p-mTOR expression were increased?P<0.05?.After H9C2 cells were transfected with miR-21mimics,the results of Western Blot showed that PTEN expression was increased and p-AKT and p-mTOR expression were decreased?P<0.05?..2.Western blot analysis showed that the expression of P62 in the DM+Vild+AAV9 group was significantly higher than that in the DM+Vild group,and the expression of LC3II/LC3I and PTEN were significantly decreased?P<0.05?.The expression of p-AKT and p-mTOR was significantly increased?P<0.05?.Conclusion:1.Vildagliptin can alleviate diabetic cardiomyopathy,reduce fibrosis and enhance cardiac function.2.miR-21 knockdown can alleviate myocardial disease under high blood glucose and enhance cardiac function by enhancing myocardial autophagy and increasing the expression of cx43.3.Vildagliptin can activate the PTEN/AKT/mTOR pathway by inhibiting the expression of miR-21,thereby increasing the level of autophagy in cardiac tissue, increasing the expression of connexin 43 and improving diabetic cardiomyopathy.