mTOR信号通路在博来霉素诱导小鼠肺纤维化中的作用机制研究

The role of mTOR signaling pathway in bleomycin-induced pulmonary fibrosis at mice

目的探讨mTOR信号通路在博来霉素诱导小鼠肺纤维化中的作用机制。方法将60只C57BL/6小鼠随机分为对照组和实验组。对实验组气管内滴注博来霉素(2.5 mg/kg)建立肺纤维化模型,对照组在相同条件下注入等体积0.9%氯化钠。在造模第21 d取小鼠肺组织标本行HE和Masson染色分析肺组织形态学变化,同时对肺泡灌洗液行细胞总数和分类分析;运用Ashcroft评分评估肺纤维化程度;Westen blot方法检测mTOR信号通路的变化;RT-PCR法检测胶原蛋白1(Collagen1)和胶原蛋白3(Collagen3)mRNA的表达水平。结果实验组与对照组相比,肺泡炎和肺纤维化程度明显加重,肺组织内充填大量炎细胞及纤维病灶。实验组Ashcroft评分较对照组显著升高(P<0.05),同时mTOR信号通路在肺组织内明显活化并伴有Collagen1和Collagen3 mRNA水平增加。结论 mTOR信号通路的异常活化促进了肺纤维化形成。

ObjectiveTo investigate the mechanism of mTOR signaling pathway in bleomycin （BLM）-induced pulmonary fibrosis in mice.MethodsSixty C57BL/6 mice were randomly divided into a control group and a BLM group. Pulmonary fibrosis model was induced by single intratracheal instillation of bleomycin （2.5 mg/kg） in the BLM group. Similarly, 0.9% saline was instilled directly into the trachea in the control group. Then all mice were sacrificed at 21 days. The lungs were collected for morphometric analysis with HE and Masson staining. The degree of pulmonary fibrosis was evaluated with Ashcroft score. The activity of mTOR signaling pathway was measured by Western blot. The level of collagen1, collagen3 mRNA was assessed with quantitative real time PCR.ResultsThe thickening alveolar septa, accumulation of inflammatory cells, and fibrous obliteration in the BLM group were exhibited predominantly compared with the control group. There was a significant difference in Ashcroft score between the BLM group and the control （P〈0.05）. Also, the activity of mTOR signaling pathway was up-regulated and the expression of collagen1 mRNA and collagen3 mRNA was increased in the BLM group.ConclusionAberrant activation of mTOR signaling pathway aggravates the pulmonary fibrogenesis.