Xinfuli Granule improves post-myocardial infarction ventricular remodelingand myocardial fibrosis in rats by regulating TGF-β/Smads signaling pathway

摘要

Background Recent clinical and experimental studies have confirmed the effects of Xinfuli Granule （XG）, a compound Chinesemedicine in the prevention and treatment of heart failure （HF）. This study aimed to investigate the effects and the mechanisms of XG onventricular reconstruction in rats with acute myocardial infarction （AMI）. Methods Sprague-Dawley rats were subjected to left anteriordescending branch ligation. The rats that survived 24 h were randomly assigned to five groups： medium-dose of XG group （MI＋XGM）,high-dose of XG group （MI＋XGH）, carvedilol group （MI＋C）, medium-dose of XG ＋ carvedilol group （MI＋C＋XGM）. Fourteen rats under-went identical surgical procedures without artery ligation, serving as sham controls. At 28 days, left ventricular weight to body weight（LVW/BW） and heart weight to body weight （HW/BW） were calculated; left ventricular ejection fraction （LVEF）, left ventricular shorteningfraction （LVFS）, left ventricular internal diameter at systole （LVIDS） were measured by ultrasound; HE staining, Masson staining, and Siriusred staining were used to assess the myocardial pathological and physiological changes as well as myocardial fibrosis area and non-infarctzone Ⅰ/Ⅲ collagen ratio. Expression of Smad3 were detected and analyzed by Western blot, immunohistochemistry and immunofluorescenceP-Smad3, Smad2 and Smad7 in the TGF-13/Smads signaling pathway were also analyzed by Western blot. Results The LVIDS （P 〈 0.01）,HW/BW （P 〈 0.05）, type UIII collagen ratio （P 〈 0.01） and myocardial collagen （P 〈 0.01） decreased significantly while the LVW/BW,LVFS （P 〈 0.05） increased significantly in MI＋XGM group as compared with those in other groups. The expression of key signal moleculesof the TGF-β/Smads signaling pathway, including Smad3, P-Smad3 and Smad2 protein were decreased, while the expression of Smad7 in-creased in both XG and carvedilol treatment groups as compared to those of the MI group （all P 〈 0.01）. Immunohistochemistry and im-munofluorescence further confirmed the down-regulated Smad3 expression. Conclusion XG can improve ventricular reconstruction andinhibit myocardial fibrosis in rats with AMI by regulating TGF-β/Smads signaling pathway.