肺泡上皮细胞间质转化在小鼠矽肺模型发生发展中的作用

Role of mesenchymal transition of alveolar epithelial cells in development of silicosis

目的 研究矽肺肺泡上皮细胞有无发生上皮间质转化(epithelial-mesenchymal transition, EMT)及其在疾病发展中的作用。方法 将30只小鼠依据体质量随机分为对照组与模型组,每组15只;采用气管暴露法建立矽肺小鼠模型。建模后第7天、14天、28天每组各处死5只小鼠,留取肺脏,采用HE染色、Masson染色观察两组小鼠肺部组织病理学改变及胶原纤维生成情况;检测肺组织E-钙黏蛋白(E-Cadherin)、N-钙黏蛋白(N-Cadherin)和波形蛋白(Vimentin)的mRNA与蛋白表达量,并进行相应的组间比较。结果 HE染色显示,对照组小鼠肺泡结构清晰,肺泡壁薄,各时间节点间对比无明显改变;模型组小鼠在建模后第7天肺部组织见明显的炎性细胞浸润,随时间的增长,肺部纤维组织明显增生,肺泡间隔增厚,造模后第28天观察到矽结节形成。Masson染色显示,对照组小鼠肺部未见明显的胶原纤维生成,而模型组小鼠肺泡间隔、支气管壁可观察到蓝染的胶原纤维沉积。模型组小鼠E-Cadherin的mRNA水平在建模后各时间点均低于对照组(P<0.05),N-Cadherin的mRNA水平在各时间节点两组差异均无统计学意义(P>0.05),Vimentin的mRNA表达水平在建模后第14天、28天高于对照组(P<0.05)。E-Cadherin、N-Cadherin、Vimentin的蛋白表达量比较显示,在建模后第7天两组间差异无统计学意义(P>0.05),在建模后第14天、28天,模型组E-Cadherin的蛋白表达量低于对照组,N-Cadherin、Vimentin的蛋白表达量则高于对照组(P<0.05)。结论 矽肺模型小鼠肺泡上皮发生的EMT参与了矽肺肺间质的纤维化病变过程。

Objective To study whether the epithelial-mesenchymal transition(EMT) occurs in silicosis alveolar epithelial cells and its role in disease development.Methods Thirty mice were randomly divided into control group and SiO2model group according to the body mass, fifteen mice in each group.The silicosis model was established by the way of trachea exposure.Then, five mice in each group were killed on the 7th, 14th and 28th day respectively, after modeling, the lungs were taken and the pathological changes of lung tissues especially the collagen fiber formation of mice in these groups were observed by HE staining and Masson staining;meanwhile, the mRNA and protein expression levels of E-Cadherin, N-Cadherin and Vimentin were detected and compared between the corresponding groups.Results The results of HE staining showed that in the mice of control group, the alveolar structure was quite clear, the alveolar wall was thin, and there was no significant change seen at any time point;while the lung tissues of mice in model group were found obvious inflammatory cell infiltration from the 7th day after modeling, the proliferation of lung fibrous tissue got more obvious, and the alveolar septum was thickened as well with the time;the formation of silicosis nodules were observed at the 28th day after modeling.Masson staining showed that there was no obvious collagen fiber formation in the lungs of the control mice, while the blue-stained collagen fiber deposition could be observed in the alveolar septum and bronchial wall of model mice.Addition, the mRNA expression levels of E-Cadherin in model mice were lower than that of control mice at all the time points(P<0.05),but its N-Cadherin mRNA expression levels between two groups at any time points after modeling had no significant difference(P>0.05),while the expressions of Vimentin mRNA of model mice were higher than that of control mice at the 14th and 28th day after modeling(P<0.05).The comparison of protein expression levels of E-Cadherin, N-Cadherin and Vimentin showed no significant difference between the two groups on the 7th day after modeling(P>0.05),on the 14th and 28th day after modeling, the protein expression of E-Cadherin in model mice was lower than that of control mice, while the protein expressions of N-Cadherin and Vimentin were higher than that of the control mice(P<0.05).Conclusion The results suggested that the EMT of alveolar epithelium in silicosis model mice involved in the process of silicosis interstitial fibrosis.