葫芦素B对压力负荷诱导的心肌纤维化的作用机制

Mechanism of cucurbitacin B underlying pressure overload-induced myocardial fibrosis

目的探讨葫芦素B对压力负荷诱导的心肌纤维化的作用机制。方法选择C57小鼠60只,随机分为假手术组、葫芦素B组、结扎术组(主动脉结扎术)、联合组(葫芦素B+主动脉结扎术),每组15只。术后1周给予葫芦素B灌胃处理[0.2mg/(kg·2d),持续到术后4周],主动脉结扎术诱导心肌纤维化模型。用免疫组织化学方法检测心脏微血管密度;免疫荧光检测α-平滑肌肌动蛋白(α-SMA)表达;运用免疫荧光染色和蛋白免疫印迹法检测CD31、CD34、α-SMA和波形蛋白表达和内皮间质转化程度。结果假手术组和葫芦素B组术后4周心脏微血管密度、α-SMA,波形蛋白、CD31、CD34表达无明显变化(P>0.05)。与假手术组比较,结扎术组术后4周心脏微血管密度、CD31、CD34表达明显下调,α-SMA、波形蛋白表达明显增加(P<0.05)。联合组术后4周心脏微血管密度、CD31、CD34表达明显高于结扎术组(4.31±1.06 vs 2.24±0.78,0.22±0.04 vs 0.05±0.02,0.12±0.02 vs0.04±0.01,P<0.05),α-SMA、波形蛋白表达明显低于结扎术组(0.31±0.03 vs 0.98±0.04,0.05±0.02 vs 0.53±0.07,P<0.05)。结论葫芦素B可以通过抑制内皮向间质转化改善压力负荷诱导的心肌纤维化。

Objective To study the mechanism of cucurbitacin B （CUB） underlying pressure over- load-induced myocardial fibrosis. Methods Sixty C57 mice were divided into sham operation group,CuB treatment group,aorta ligation group,CuB＋aorta ligation group （15 in each group）. The animals received intragastric gavage （0.2 mg/kg · 2 d） one week after operation and a myocardial fibrosis model of mice was induced by aorta ligation 4 weeks after operation. Microvascular density （MVD） was detected with immunohistochemical staining. Expressions of a-SMA, CD31, CD34,vimentin and endothelial-mesenchymal transition （EndMT） were detected by Western blot with immunofluorescence staining. Results No significant difference was found in cardiac MVD, and expression level of a-SMA,vimentin,CD31 and CD34 between sham operation group and CuB group 4 weeks after operation （P〉0.05）. The cardiac MVD and expression level of CD31 and CD34 were significantly lower while the expression level of a-SMA and vimentin was significantly higher in aorta ligation group than in sham operation group 4 weeks after operation （P〈0.05）. The cardiac MVD and expression level of CD31 and CD34 were significantly higher while the expression level of a-SMA and vimentin was significantly lower in CuB＋aorta ligation group than in aorta ligation group 4 weeks after operation （P〈0.05）. Conclusion CuB can attenuate cardiac fibrosis by regulating EndMT.