外源性硫化氢调节TGF-β1/Smad7信号通路改善高同型半胱氨酸血症所致的大鼠心肌纤维化

Exogenous hydrogen sulfide alleviates hyperhomocysteinemia-induced myocardial fibrosis in rats by regulating TGF-β1/Smad7 signaling pathway

摘要:

目的：观察外源性硫化氢（hydrogen suifide，H2S）对高同型半胱氨酸血症（hyperhomocysteinemia，HHcy）诱导的大鼠心肌纤维化及转化生长因子-β1（transforming growth factor-β1，TGF-β1）和Smad7蛋白表达的影响。方法：将40只成年雄性SD大鼠随机均分为对照（Control）组、模型（HHcy）组、H2S干预模型（HHcy+H2S）组和H2S对照（H2S）组，每组10只。本实验模型大鼠的建立通过将L-蛋氨酸（10 g/L）加入大鼠的饮用水，持续10周喂养建立。建模成功后，HHcy+H2S组及H2S组大鼠每日经腹内注射硫氢化钠（sodium hydrosulfide，NaHS）溶液，持续干预4周。各组大鼠心肌胶原纤维沉积情况由Masson染色法观察，心肌组织中Ⅲ型胶原的表达情况由免疫组织化学染色法检测，CBS、TGF-β1和Smad7蛋白的表达情况通过Western blot检测。结果：与对照组相比，模型组心肌细胞排列紊乱、胶原沉积明显增加，心肌组织中Ⅲ型胶原沉积明显增加（P=0.000），TGF-β1蛋白表达明显升高（P=0.004），CBS（P=0.006）及Smad7（P=0.001）蛋白表达水平明显下调；与模型组相比，HHcy+H2S组大鼠心肌细胞排列相对整齐、胶原沉积相对减轻，组织中Ⅲ型胶原沉积减轻（P=0.003），TGF-β1蛋白表达相对下调（P=0.006），CBS（P=0.005）及 Smad7（P=0.000）蛋白表达水平增加。结论：外源性硫化氢可以改善HHcy诱导的大鼠心肌纤维化，其调节机制可能与TGF-β1/Smad7信号通路有关。

Abstract:

Objective：To observe the effect of exogenous hydrogen suifide（H2S） on myocardial fibrosis and expression of transforming growth factor-β1（TGF-β1） and Smad7 in hyperhomocysteinemia（HHcy）-induced rats. Methods：A total of 40 adult male SD rats were randomly assigned into 4 groups（n=10）：the control group（Control），the model group（HHcy），the H2S-intervention model group（HHcy+H2S） and the H2S-intervention normal group（H2S）. L-methionine（10 g/L） was added into the drinking water for consecutive ten weeks to establish the model. After successful modeling，sodium hydrosulfide（NaHS） was intraperitoneally injected into the rats in the HHcy+H2S group and the H2S group for consecutive four weeks. Masson staining method was used to observe the deposition of myocardial collagen，immunohistochemical staining was used to detect the expression of Collagen Ⅲ and Western blotting was used to determine the expression of CBS，TGF-β1 and Smad7. Results：Compared with the control group，cardiomyocytes were arranged in disorder，the collagen deposition was significantly increased，the expression of collagen Ⅲ was significantly increased（P=0.000），the expression of TGF-β1 was increased apparently（P=0.004），and CBS（P=0.006） and Smad7（P=0.001） proteins were obviously down-regulated in the HHcy group. Compared with the HHcy group，cardiomyocytes were arranged in a relatively order man－ner，the collagen deposition was comparatively reduced，the ex－pression of collagen Ⅲ was relatively decreased（P=0.003），the expression of TGF-β1 was down-regulated distinctly（P=0.006），and CBS（P=0.005） and Smad7（P=0.000） proteins were increased in the HHcy+H2S group. Conclusion：H2S may improve myocar－dial fibrosis in hyperhomocysteinemia-induced rats and its mechanism may be related to the regulation of TGF-β1/Smad7 signaling pathway.