Objective      To explore the establishment of murine model method for bronchiolitis obliterans (BO).       Methods      C57BL/6 mice(SPF) were randomly divided into normal control group and BO model group and 6 mice per group. The mice of BO group were intratracheal instillated with diacetyl (DA) (490 mg/mL

500 mg/kg) and the mice in control group with sterile distilled water. The rest of the experimental conditions and methods were the same. The mice were kept in SPF class animal center for 3 or 7 d to collect specimens. The mice were dynamically observed the general status

body weight

pulmonary function

cell counts

inflammatory cell count of bronchoalveolar lavage fluid

as well as the pathological and HE staining for lung slices.       Results      The model group mice were given DA (500 mg/kg) after 1 d and they presented wheezing

rapid breathing and other symptoms

the weight was significantly lower than the control group (P0.05). Compared with the control group

the lung function (aerosolized methacholine concentration was 50 mg/mL) enhanced pause (Penh) was increased significantly (P0.05). Model mice inflammatory cell count and classification counting neutrophils were significantly higher than the control group (P0.05) in 3 d

and the total cells and lymphocytes

macrophages were significantly higher than that of the control group (P0.05) in 7 d. Pathological section HE staining showed typical BO changes (around the 3 d， model group bronchial lumen and infiltration of inflammatory cells

luminal severe occlusion

tissue in the acute stage of severe bleeding; In 7 d

basal cells were severe necrosis

airway epithelial cells were attached to the substrate

but seen obvious cell hyperplasia and hypertrophy

cell nucleus lost seriously

inflammatory cell infiltration in the lumen

and the lumen wall thickening

fibrosis).       Conclusion      The mouse model of bronchiolitis obliterans (BO) should be established successfully by intratracheal instillation DA (500 mg/kg) one time.