甘蔗叶多糖对大鼠心肌梗死后心肌纤维化的影响

Effects of sugarcane leaf polysaccharide on myocardial fibrosis after myocardial infarction in rats

目的:探讨甘蔗叶多糖对心肌梗死后心肌纤维化的影响及可能调控机制。方法:采用结扎大鼠冠状动脉左前降支建立大鼠心肌梗死模型,造模成功后将26只大鼠按随机数字表法分为模型组(MI组,n=13)和处理组(SLP组,n=13),另设只穿线未予结扎的假手术组(Sham组,n=8)。造模成功后第1天开始连续灌胃4周,SLP组灌入甘蔗叶多糖溶液(4 g/L),按1 m L/100 g大鼠体重给药,MI组及Sham组灌入等量的0.9%生理盐水。4周后,梗死周边区心肌组织分别采用实时荧光定量PCR(RT-qPCR)检测TGF-β1、NF-κB mRNA表达;western blotting检测p-ERK1/2/ERK1/2蛋白表达;Masson染色及免疫组化检测Ⅰ型、Ⅲ型胶原蛋白的表达。结果:MI组、SLP组TGF-β1、NF-κB mRNA表达较Sham组均明显升高,SLP组较MI组明显抑制TGF-β1、NF-κB mRNA表达(P<0.05);p-ERK1/2/ERK1/2/蛋白检测结果显示,MI组、SLP组表达高于Sham组,而SLP组表达低于MI组(P<0.05);仅MI组、SLP组梗死周边区有纤维化,MI组与SLP组的CVF明显高于Sham组,而SLP组纤维化、CVF明显低于MI组(P<0.05);Ⅰ型、Ⅲ型胶原蛋白检测结果显示,MI组、SLP组胶原蛋白的MIOD较Sham组明显升高(P<0.05),而SLP组较MI组明显减少(P<0.05)。结论:甘蔗叶多糖能减轻大鼠心肌梗死后梗死周边区心肌间质纤维化,其机制可能与下调pERK1/2/ERK1/2蛋白的表达,抑制促纤维化基因TGF-β1、NF-κB的mRNA表达有关。

Objective:To investigate the effect and mechanism of sugarcane leaf polysaccharide(SLP)on myocardial fibrosis after myocardial infarction(MI)in rats.Methods:The rat MI modelwas established by ligation of the left anterior descending(LAD)coronary artery.A total of 26 rats were randomly divided into MI group and SLP group,with 13 rats in each group.Eight rats in the sham-operated group were subjected to surgical manipulation without ligation of the LAD coronary artery.On day 1 post-modeling,the rats in SLP group were given 4 g/L SLP(1 m L/100 g body weight)for 4 weeks by gavage.MI group and sham-operated group rats were administrated equal volume of normal saline.The mRNA expressions of TGF-β1 and NF-κB in the infarcted area of myocardial tissuess were detected by RT-qPCR.The protein expressions of p-ERK1/2 and ERK1/2 were detected by western blotting.The content of collagen in myocardial tissues of the infarcted area of left ventricle was measured by Masson staining and immunohistochemistry.Results:The mRNA expressions of TGF-β1 and NF-κB,the protein levels of p-ERK1/2 and collagen,myocardial fibrosis and collagen volume fraction(CVF)in MI group and SLP group were significantly increased compared with sham-operated group(P<0.05).Compared with MI group,the mRNA expressions of TGF-β1 and NF-κB,the protein levels of p-ERK1/2 and collagen,myocardial fibrosis and CVF in SLP group was significantly decreased(P<0.05).Conclusion:SLP could alleviate myocardial interstitial fibrosis in the peripheral myocardial infarction area after myocardial infarction in rats,and its mechanism may be related to down-regulation the expression of p-ERK1/2/ERK1/2 protein,inhibition the mRNA expression of pro-fibrotic gene TGF-β1 and NF-κB.