中文摘要：

【摘要】目的探讨miR．149在SiO2诱导的肺纤维化中对白细胞介素-6（IL-6）表达水平的调节作用。方法（1）建立SiO2粉尘诱导的小鼠肺纤维化模型，实时荧光定量聚合酶链式反应（quantitativereal—timepolymerasechainreaction，qRT-PCR）检测小鼠肺组织miR-149表达，蛋白免疫印迹法（Westernblot）和免疫组织化学法观察白细胞介素．6（IL．6）的蛋白表达情况。（2）应用具有肺泡Ⅱ型上皮细胞特性的（A549）及支气管上皮细胞（HBE）构建SiO2粉尘刺激的呼吸系统上皮细胞模型，应用qRT—PCR检测miR．149水平，用Westernblot法检测IL．6蛋白表达情况。（3）通过体外转染miR-149相似剂（mimics）及抑制剂（inhibitors）至A549细胞，Westernblot法检测细胞表达炎症因子IL-6蛋白的表达情况。（4）双抗夹心酶联免疫吸附试验（ELISA）检测煤工尘肺患者血清中IL．6蛋白的表达情况。结果（1）在SiO2诱导的小鼠肺纤维化模型中，与空白对照组比较，SiO2处理后的3个时间点，小鼠肺组织miR-149表达明显下调，而IL．6蛋白表达明显上调，差异有统计学意义（P〈0．01）。（2）在粉尘刺激上皮细胞模型中，A549细胞及HBE细胞经SiO2刺激后，IL-6蛋白表达上调，miR-149表达量明显下调，差异有统计学意义（P〈0．01）。（3）对A549细胞转染miR-149相似物及抑制剂后实验结果显示，高表达miR．149后，A549细胞IL．6蛋白表达下调，反之亦然。（4）与对照组比较，Ⅱ期、Ⅲ期煤工尘肺组血清IL．6水平明显升高，差异有统计学意义（P〈0．01）。结论（1）SiO2粉尘所诱导的肺纤维过程中miR-149表达降低，IL-6蛋白表达增高。（2）miR-149可负调控细胞IL-6的表达水平。

英文摘要：

Objective To investigate the regulatory effect of miR-149 on interleukin-6 （IL-6） expression in silica-induced pulmonary fibrosis. Methods A mouse model of pulmonary fibrosis was established using silica dust; the level of miR-149 in the lung tissues of mice with silica-induced pulmonary fibrosis was measured by quantitative real-time polymerase chain reaction （qRT-PCR）, while the protein expression of IL-6 was measured by immunohistochemistry and Western blot. Type II alveolar epithelial cells （A549） and bronchial epithelial cells （HBE） were exposed to silica dust to establish a model; the level of miR-149 was measured by qRT-PCR, while the protein expression of IL-6 was measured by Western blot. A549 cells were transfected with miR-149 mimics and inhibitor in vitro, and the cellular expression of IL-6 was measured by Western blot. Serum samples from patients with coal workers＇ pneumoconiosis were examined by double-antibody sandwich ELISA to measure the protein expression of IL-6. Results At three time points after silica treatment, the miR-149 expression in lung tissues was significantly down-regulated while an evident increase in IL-6 expression was observed in lung tissues （P〈0.01）. Silica-stimulated epithelial cells （A549 and HBE） had up-regulated IL-6 expression and down-regulated miR-149 expression （P〈0.01）. Increased levels of miR-149 attenuated IL-6 expression, whereas adverse results were found when miR-149 was inhibited. Compared with that in control group, serum level of IL-6 was significantly increased in patients with stage Ⅱ and Ⅲ coal workers＇ pneumoconiosis （P〈0.01）. Conclusion Down-regulation of miR-149 and up-regulation of IL-6 might be involved in the progression of silica-induced pulmonary fibrosis; miR-149 could negatively regulate IL-6 expression.