Objective:To observe the presence of dentritic cells (DC) in lung tissues of rat models of chronic obstructive pulmonary disease (COPD) and the influence of budesonide and ipratropium bromide on the number of DCs.Methods: Sixty male SD rats were randomly divided into four groups(n=15): control group,COPD model group,budesonide treatment group and ipratropium biomide treatment group.The COPD rat models were established by intratracheal instillation of lipopolysaccharide (LPS) twice and exposure to tobacco smoke for 4 weeks.Drug inhalation group received inhalation of budesonide (Pulmicort) or ipratropium bromide (Atrovent) since the second week.The rats were sacrificed at the 31th day.Lung slices were observed with H-E staining for pathological changes and the status of DC were determined by immunohistochemical method.Results: The COPD model group,budesonide treatment group, and ipratropium biomide treatment group all had the pathological changes of COPD,and their DC numbers were significantly higher than that in the control group (P<0.01).DC number in Pulmicort treatment group was significantly less than that in the COPD model group (P<0.01),and there was no significant difference between the Atrovent treatment group and the COPD model group.Conclusion: The pulmonary DCs play an important role in the pathogenesis of COPD.Pulmicort can decrease the number of DCs in rat model of COPD,and ipratropium bromide has no obvious effect on DC number.