Study On The Mechanism Of Yixintai Regulating The Expression Of CaN And NFAT₃ Protein In Myocardial Tissue Of Rabbits With Heart Failure After Myocardial Infarction

Objective:To investigate the mechanism of Yi Xin Tai on the expression of Ca N and NFAT₃proteins in myocardial tissue of rabbits with heart failure after myocardial infarction.Methods:The rabbit model of chronic heart failure was established by ligation of the anterior descending branch of the left coronary artery and intragastric administration of propyl thiouracil.The model rabbits were randomly divided into five groups:model group,low-dose Yi Xin Tai group,medium-dose Yi Xin Tai group,high-dose Yi Xin Tai group and losartan potassium group.In addition,there is another mock surgical group.After successful modeling,each group was gavaged with corresponding drugs,and the model group and the mock surgical group were gavaged with normal saline once a day for 4 weeks.After 4 weeks of administration,ANP and BNP were detected by ELISA,cardiac function indicators were detected by echocardiography,m RNA and protein expressions of Ca N,NFAT₃and?-MHC were detected by RT-PCR and Western blot,and the pathological structure of myocardium was observed by optical microscope.Results:1.After 4 weeks of medication,compared with the CHF model group,serum ANP and BNP levels in each medication group decreased significantly?P<0.01?.The levels of serum ANP and BNP in Yi Xin Tai middle and high dose groups and losartan potassium group were better than those in low dose group?P<0.05?.2.After 4 weeks of medication,compared with the CHF model group,the LVEF,LVFS,and E/A of each medication group were significantly increased?P<0.01?.The elevation levels of LVEF,LVFS,and E/A in the middle and high dose groups of Yi Xin Tai and the losartan potassium group were better than those in the low dose group?P<0.05?.3.After 4 weeks of medication,compared with the CHF model group,the degree of edema and necrosis of myocardial cells in each administration group under optical microscope was reduced,and the degree of inflammatory cell infiltration was improved.4.After 4 weeks of medication,compared with the CHF model group,the expression of Ca N,NFAT_3,?-MHC m RNA and protein in myocardium of each administration group was decreased?P<0.05?.The expression levels of Ca N,NFAT_3,?-MHC m RNA and protein in myocardium of Yi Xin Tai middle and high dose group and losartan potassium group were better than those of low dose group?P<0.05?.Conclusion:1.Yi Xin Tai can down-regulate serum ANP and BNP levels in CHF rabbits after myocardial infarction,and can increase LVEF,LVFS and E/A,indicating that Yi Xin Tai can improve cardiac function.2.Yi Xin Tai can improve the pathological changes of myocardial tissue in CHF rabbits after myocardial infarction,alleviate the degree of the edema and necrosis of myocardial cells,and reduce the inflammatory cell infiltration.3.Yi Xin Tai can reduce the expression of Ca N,NFAT₃,?-MHC m RNA and protein in CHF rabbit myocardium after myocardial infarction,indicating that Yi Xin Tai can improve myocardial remodeling by regulating Ca N/NFAT₃pathway and its downstream proteins.