An improved modeling method of bleomycin-induced pulmonary fibrosis

LI Qiao; WANG Miaofeng; TIAN Yu; ZHAO Feng

doi:10.13276/j.issn.2097-1656.2024.04.012

Abstract：Objective To establish bleomycin-induced pulmonary fibrosis model in mice,and compare the differences of two different administration modes:transtracheal instillation and transtracheal inhalation.Methods A total of 46 male C57BL/6 mice aged 6-8 weeks were selected,and 6 mice were randomly divided into transtracheal instillation group and transtracheal inhalation group,with 3 mice in each group.The distribution of methylene blue in the lungs and stomach of the mice was observed after they were instilled and inhaled methylene blue after anesthesia.Another 40 mice were randomly divided into transtracheal instillation+normal saline group,transtracheal inhalation+normal saline group,transtracheal instillation+bleomycin group,and transtracheal inhalation+bleomycin group.The mental state,body mass changes and survival status of mice in each group were observed after modeling,and lung tissues were collected on the 21st day for histology,hydroxyproline and TGF-β,α-SMA and COL1A1 protein levels by Western blotting.Results In the transtracheal instillation group,methylene blue was distributed unevenly and restrictively in both lungs,with varying degrees of gastric residue.In the transtracheal inhalation group,methylene blue was distributed evenly and diffusively in both lungs,without obvious gastric residue.Compared with the two control groups,the two model groups had poor mental state,significant body mass loss,high mortality,severely damaged alveolar structure of lung tissue of mice,a large amount of collagen deposition,and significantly increased content of hydroxyproline(P＜0.05).Western blotting showed that the expressions of TGF-β,α-SMA,and COL1A1 proteins in lung tissue were significantly increased(P＜0.05).Conclusion The fibrotic lesions of transtracheal inhalation+bleomycin group are more evenly distributed and the indexes are relatively stable,which is an ideal method to establish pulmonary fibrosis model.