ABSTRACT
Objective:To determine the characteristics and differences in bleomycin-induced lung ifbrosis model by repeated low-dose intravenous injection and single dose intratracheal instillation of bleomycin. Methods:Forty male ICR (Institute for Cancer Research) mice were randomly divided into a model group I, a model group II, and 2 control groups (10 mice in each group). In model group I, bleomycin was injected intravenously at 10 mg/(kg·d) for 14 consecutive days;and in model group II, bleomycin was instilled intratracheally at 5 mg/kg. The 2 control groups were given isotonic saline solution. At the 28th day, the mice were sacrificed and the bronchoalveolar lavage lfuid (BALF) was collected. The total cells and proteins in the BALF, pulmonary coeffcient, and hydroxyproline (HYP) content were determined. The pathological changes were observed by the eosin staining and Masson's trichrome staining. Results:1) Both intravenous injection and intratracheal instillation of bleomycin resulted in severe and extensive inlfammation and ifbrosis in the lungs. The total cells and proteins in the BALF, HYP content, pulmonary coeffcient and the pathological score of pulmonary ifbrosis were all signiifcantly increased in the 2 model groups (P0.05). Conclusion:The pulmonary fibrosis model can be successfully established by intravenous injection or intratracheal instillation of bleomycin, but the sites of pulmonary ifbrosis are different. The histological changes caused by the repeated low-dose intravenous injection of bleomycin is more similar to idiopathic pulmonary ifbrosis than that by the single dose intratracheal instillation.