丹参素对压力负荷后小鼠心功能和心肌纤维化的影响

Effects of danshensu on cardiac function and myocardial fibrosis in pressure-overloaded mice

目的 观察丹参素（DSS）对压力负荷后小鼠心功能和心肌纤维化的影响.方法 40只C57BL/6雄性小鼠,随机分为Sham-Saline、Sham-DSS、TAC-Saline和TAC-DSS组,每组10只.主动脉缩窄术（TAC）制备小鼠心室重构模型,术后1周根据分组给予不同处理7周.心脏超声检测心功能,苏木素-伊红（HE）染色检测心肌细胞横截面积和Masson染色检测心肌纤维化程度;Westernblot检测转化生长因子-β1 （TGF-β1）信号通路相关蛋白表达.结果 心脏超声提示TAC术后小鼠左室射血分数（LVEF）和左室缩短分数（LVFS）降低[LVEF：（48.19±1.11）％和（80.78±1.30）％;LVFS：（24.36±0.63）％和（42.87 ±1.09）％;P＜0.05],DSS能改善TAC引起的心功能的降低[LVEF：（57.35±1.09）％和（48.19±1.11）％;LVFS：（29.88 ±0.68）％和（24.36 ±0.63）％;P＜0.05];HE染色提示TAC术后心肌细胞横截面积增加[（379±25） μm2和（192±12） μm2,P＜0.05],而DSS能够降低TAC引起的心肌细胞横截面积的增大[（264±18） μm2和（379±25） μm2,P＜0.05;Masson染色提示TAC术后心肌纤维化程度增加[（11.34±1.43）％和（2.18±0.14）％,P＜0.05],而DSS能够降低TAC引起的心肌纤维化[（5.26±1.17）％和（11.34 ±1.43）％,P＜0.05];Western blot提示TAC术后TGF-β1、p-Smad2和p-Smad3蛋白表达增加,Smad7蛋白表达下降（TGF-β1：3.07 ±0.43和1.02±0.29;p-Smad2：2.74±0.22和0.98 ±0.18;p-Smad3：2.21 ±0.16和1.01±0.11;Smad7：0.45±0.16和0.96±0.23;P＜ 0.05）;DSS能够抑制TGF-β1、p-Smad2和p-Smad3蛋白表达,上调Smad7蛋白表达（TGF-β1：1.47±0.31和3.07±0.43;p-Smad2：1.88±0.27和2.74 ±0.22;p-Smad3：1.27 ±0.17和2.21 ±0.16;Smad7：0.91 ±0.24和0.45 ±0.16,P＜0.05）.结论 丹参素可能通过抑制TGF-β1/Smad信号通路来改善压力负荷后心肌纤维化,从而改善心脏功能,抑制心室重构.

Objective To observe the effect of Danshensu （DSS） on cardiac function and myocardial fibrosis in pressure-overloaded mice.Methods C57BL/6 male mice were randomly divided into four groups：Sham-Saline,Sham-DSS,TAC-Saline and TAC-DSS.Mice ventricular remodeling model were established by transverse aortic constriction （TAC） operation.One week later,the mice were fed with DSS or Saline for 7 weeks.After echocardiographic evaluation,cardiomyocyte cross-sectional area and myocardial fibrosis were determined by hematoxylin and eosin （HE） and Masson staining,respectively.Western blotting analysis was performed to detect the expression of transforming growth factor-β1 （TGF-β1）/Smad signaling pathway related proteins.Results Compared with Sham-Saline group,the left ventricular ejection fraction and fraction shortening in TAC-Saline group were reduced [（48.19 ± 1.ll）% vs.（80.78±1.30）%;（24.36±0.63）% vs.（42.87±l.09）%,P〈0.05],whichcouldbe improved by DSS [（57.35 ± 1.09） % and （29.88 ± 0.68） %,respectively,P 〈 0.05].HE staining indicated an enlargement in cardiomyocyte cross-sectional area after TAC [（379 ± 25） μm2 vs.（192 ±12） μm2,P 〈 0.05],which could be ameliorated by DSS [（264 ± 18） μm2,P 〈 0.05].Masson staining demonstrated that the degree of myocardial fibrosis was increased following TAC [（11.34 ± 1.43） % vs.（2.18 ± 0.14） %,P 〈 0.05],which could be mitigated by DSS intervention [（5.26 ± 1.17） %,P 〈0.05].In addition to a reduction in Smad7 protein content,an increase in the protein level of p-Smad2,p-Smad3 and TGF-β1 were also observed in TAC-Saline group compared to Sham-Saline group （P 〈 0.05）;compared with TAC-Saline group,TAC-DSS group showed a reduced expression of p-Smad2,p-Smad3 and TGF-β1 and an increased expression of Smad7 （P 〈 0.05）.Conclusion DSS may ameliorate myocardial fibrosis via TGF-β1/Smad signaling pathway,thus improving the cardiac function and ventricular remodeling after pressure overload.