Abstract: Objective To provide a better animal model of pulmonary fibrosis by comparing the model establishment in different strains of mice. Methods BALB/c and C57BL/6 mice were divided into model and control group respectively, which received intratracheal injection of bleomycin (BLM) and normal saline , respectively. The mice were sacrificed 28 days after treatment. The masson mass and the degree of fibrosis in the left pulmonary lobe were observed by light microscope. Hydroxyproline contents in right pulmonary lobe were measured. Results The pulmonary consolidation and collagen deposition appeared in all bleomycin groups especially in the C57BL/6 group. Hydroxyproline contents in pulmonary tissue in C57BL/6 mice was the highest and normal saline group was the lowest one. Conclusion The pulmonary fibrosis model can be established in BALB/c and C57BL/6 mice by intratracheal injection of bleomycin, while the C57BL/6 mice was more suitable.

Key words: Strains of mice, Pulmonary fibrosis, Animal model, Bleomycin