Effect And Its Mechanism Of Sugarcane Leaf Polysaccharide On Left Ventricular Function In Myocardial Infarction Rats

Objective : To investigate the effect of sugarcane leaf polysaccharide on left ventricular function after myocardial infarction in rats as well as mechanisms involved in.Provide the basis for the development and utilization of sugarcane leaf polysaccharide.Methods : A rat model of AMI was established via permanent ligation of the left anterior descending coronary artery,and then 30 rats were randomly divided into model group(MI group),sugarcane leaf polysaccharide group(SLP group),in addition,Sham operation group was added,however,the rat in Sham group were only wearlined without ligation.From the first day after modeling,the rats were intragastrically administered for 4 consecutive weeks.The SLP group was infused with a concentration of 4 mg/mL and the dose was 100 g/mL sugarcane leaf polysaccharide solution.The MI group and Sham group were infused with the same dose of physiological saline.After 4 weeks,echocardiography was performed to evaluate the cardiac function in rats.Blood was collected from the apex by open thoracotomy,and the plasma BNP concentration was measured by ELISA.Then,the rat's heart was obtained,HE staining and TUNEL was used to detect apoptosis of myocardial tissue in the peripheral area of infarction,we also detected the mRNA expression of BCL-2,BAX,Caspase3,TGF-?1 and NF-?Bby Real-time PCR and detected the protein expression of p-AKT/AKT,pPI3K/PI3 K,p-ERK1/2/ERK1/2 by Western blot.In addition,Masson staining and immunohistochemistry were used to detect the expression of Type I and Type III collagen protein in area of myocardial tissue around the infarction.Results1.EF were obviously decreased in the MI group and SLP group than those in the Sham group,the EDV was significantly higher in the SLP group and MI group than in the Sham group.Compared with the MI group,the EF in the SLP group were significantly increased than those in the MI group,and the EDV was obviously lower than the MI group(p<0.05).2.Compared with the Sham group,the concentrations of BNP in plasma of MI group and SLP group were significantly increased,whereas,compared with the MI group,the concentrations of BNP in plasma of SLP group were obviously lower than those of MI group(p<0.05).3.The myocardial cells of Sham group were arranged neatly,and the cell lines were clear,showing the morphology of normal myocardial cells.After myocardial infarction,myocardial cells was observed in MI group arranged disorder,intercellular space is not clear,the nucleus was large and darkly stained,Peripheral inflammatory cell infiltration,and the myocardium fibers were thickened and prolonged,a typical performance in fibrosis after myocardial infarction.And sugarcane leaf polysaccharide processed,SLP group myocardial cell were arranged more neatly in the myocardial infarction area,intercellular space more clear than the MI group,inflammatory cells infiltrating was decreased,and a small amount of myocardial hypertrophic hypertrophy was observed.4.There was no cardiomyocyte apoptosis in the Sham group.Myocardialapoptosis was observed in the MI group and the SLP group in the infarct marginal zone.However,the apoptosis of myocardial cells of SLP group was significantly decreased than that of MI group(p<0.05).5.Compared with Sham group,the expression of BCL-2,BAX,Caspase3,TGF-?1,NF-?B mRNA in MI group and SLP group were significantly increased than Sham group,while the expression of BCL-2 mRNA in SLP group was further increased,and the expression of BAX,Caspase3,TGF-?1and NF-?B mRNA was obviously inhibited(p<0.05).6.The expression of p-AKT/AKT,p-PI3K/PI3 K protein in the MI group and SLP group was decreased than the Sham group,the expression of pERK1/2/ERK1/2 protein in the MI group and SLP group increased than the Sham group,however,the expression of p-AKT/AKT,p-PI3K/PI3 K protein in the SLP group increased than the MI group,the expression of pERK1/2/ERK1/2 protein in the SLP group significantly decreased than the MI group(p < 0.05).7.There was no fibrosis in the peripheral infarction area of Sham group.There were fibrosis in the peripheral infarction region of MI group and SLP group,the CVF of MI group and SLP group was obviously higher than that of Sham group,however,compared with MI group,SLP group fibrosis is significantly lower than MI group around the Infarction area,the CVF of SLP group was obviously lower than MI group(p < 0.05).8.The expression of ?type and ? type collagen protein of Sham group were not detected,myocardial matrix around the area of infarction of MI group and SLP group had the expression of ?type and ? type collagen protein,the MIOD of ?type and ? type collagen protein in MI group and SLP group significantly increased than that of Sham group,whereas compared with the MIgroup,the expression of ?type and ? type collagen protein of SLP group is decreased significantly than MI group,the MIOD of ?type and ? type collagen protein in SLP group is lower obviously than that of MI group(p <0.05).Conclusion: Sugarcane leaf polysaccharide can improve left ventricular function after myocardial infarction in rats for 4 weeks.The mechanism may be related to the reduction of myocardial cell apoptosis and myocardial fibrosis after myocardial infarction in rats.