Dysbiosis of lung commensal bacteria in the process of lung epithelial-mesenchymal transition in mice with silicosis / 中国职业医学

ABSTRACT

@#Objective - To investigate the effect of lung flora dysbiosis on the process of pulmonary fibrosis and lung epithelial （ ） Methods - mesenchymal transition EMT in mice with silicosis. Male C57BL/6 mice of specific pathogen free grade were ， ， ， （ ） randomly divided into the blank control group silicosis model group solvent control group vancomycin VM + ampicillin （ ） ， （ ） （ ） ， AMP group metronidazole MNZ + neomycin NEO group and mixed treatment group 12 mice in each group. Except for ， ， the blank control group which was given 20.0 µL of 0.9% NaCl solution the other five groups of mice were dosed with 20.0 µL of silica dust suspension at a mass concentration of 250.0 g/L using a single tracheal drip to establish the silicosis mouse model. ： The intranasal drip method was used to treat silicosis mice in each group as following mice in the solvent control group were - ； ； given double distilled water mice in the VM+AMP group were given VM at a mass concentration of 0.5 g/L and AMP at 1.0 g/L ； mice in the MNZ+NEO group were given MNZ at a mass concentration of 1.0 g/L and NEO at 1.0 g/L mice in the mixed ， treatment group were given the same doses of the four antibiotics mentioned above all in a drip volume of 50.0 µL. Silicosis ， ， mice were treated seven days and half an hour before silica dusting and 7 14 and 21 days after silica dusting. Mouse lungtissue was collected aseptically 28 days after silica dusting. Hematoxylin eosin and Masson trichrome staining methods were - used to observe the pathological changes. Western blotting was used to detect the relative protein expression of α smooth muscle （ - ）， - （ - ） （ ） actin α SMA E cadherin E CAD and vimentin VIM . Immunohistochemistry was used to detect the relative expression of - - E CAD and VIM. Real time fluorescence quantitative polymerase chain reaction was used to detect the expression levels of （Col1a2） Results collagen type Ⅰ alpha 2 mRNA in lung tissues. The histopathological results showed that the alveoli of the ， blank control group were thin and structurally intact with few surrounding infiltrating inflammatory cells and no abnormal ， distribution of collagen fibers. The alveoli of the silicosis model group were structurally disorganized with a large number of ， ， infiltrating inflammatory cells thickened alveolar walls and cellular fibrous nodules with abundant blue collagen deposit. In the ， ， VM+AMP group MNZ+NEO group and the mixed treatment group the inflammation and fibrosis were reduced with diferent degrees in the lung tissues compared to the silicosis model group and the solvent control group. The relative expression levels of - ， Col1a2 α SMA VIM protein and mRNA in lung tissues of mice in the silicosis model group were higher than those in the blank （ P ）， -CAD control group all <0.05 and the relative expression levels of E protein were lower than those in the blank control （P ） - ， Col1a2 group <0.05 . The relative expression levels of α SMA VIM protein and mRNA in lung tissues of mice in the MNZ+ （ P ）， -CAD NEO group and the mixed treatment group were lower all <0.05 and the relative expression levels of E protein were （P ）， Conclusion higher <0.05 when compared with the silicosis model group and the solvent control group. Pulmonary fibrosis ， - was reduced in silicosis mice with interventions in lung flora where anaerobic and gram negative bacteria affected pulmonary fibrosis and dysbiosis of the lung flora affected pulmonary EMT.