二氧化硅影响人肺成纤维细胞α-平滑肌肌动蛋白表达的实验研究

目的 探讨二氧化硅（SiO2）体内体外影响人肺成纤维细胞α-平滑肌肌动蛋白（α-SMA）的表达情况.方法 体内实验以SiO2灌注的大鼠矽肺模型为研究对象,实验组32例（7、14、21和28d各8例）,对照组32例.免疫组化法检测肌成纤维细胞标志物α-SMA的表达;体内实验以人肺成纤维细胞（HLF-02）为研究对象,分别用SiO2刺激的体外小鼠腹腔巨噬细胞系（RAW264.7细胞）上清液、SiO2未刺激的RAW264.7细胞上清液、SiO2悬液以及转化生长因子β1（TGF-β1）作用24 h,免疫印迹法检测α-SMA的表达变化情况.结果 （1）染尘28 d大鼠肺组织有表达α-SMA阳性的肌成纤维细胞出现.（2）RAW264.7细胞上清液（SiO2）可诱导HLF-02细胞α-SMA的表达,而TGF-β1可明显上调α-SMA表达.（3）单纯SiO2悬液对HLF-02细胞α-SMA的表达没有影响.结论 肌成纤维细胞与矽肺纤维化进展有关;体外条件下肌成纤维细胞的出现不是SiO2直接作用的结果,而与SiO2活化巨噬细胞分泌的介质TGF-β1有关.

Effects of silicon dioxide on expression of α-smooth muscle actin in human lung fibroblats

OBJECTIVE: To investigate the effects of SiO(2) on the expression of alpha-smooth muscle actin (alpha-SMA) in human lung fibroblasts in vitro and vivo. METHODS: The experimental group comprised 32 rats while 32 rats were included in the control. In vivo, the expression of alpha-SMA in lung tissues of rats exposed to SiO(2), the supernate of RAW264.7 cells, SiO(2) and the growth factor beta(1) (TGF-beta(1)) were investigated, respectively. RESULTS: (1) alpha-SMA positive myofibroblasts appeared in the lung tissues of the 28th day groups exposed to SiO(2). (2) The expression of alpha-SMA in HLF-02 cells was unregulated by TGF-beta(1) and supernate of RAW264.7 cells exposed to SiO(2). (3) The expression of alpha-SMA in HLF-02 cells was not induced by SiO(2). CONCLUSION: Myofibroblasts related to silicosis, and the appearance of myofibroblasts (in vitro) are independent on direct stimulation by SiO(2), but related to the mediator (TGF-beta(1)) secreted by SiO(2) stimulated macrophages.