Abstract: Objective:To detect the expression of indoleamine 2,3-dioxygenase (IDO)in lung tissue and the level of interferon γ(IFN-γ) in serum and bronchoalveolar lavage fluid(BALF), and to explore the role of IDO in the pathogenesis of bronchial asthma and its relationship with IFN-γ.Methods:Select 21 SPF BALB/C mice. They were randomly divided into control group, intervention group and asthma group, with 7 mice in each group. A mouse model of asthma was established by sensitization and stimulation of dust mites extract. The changes of airway inflammatory cells were observed by hematoxylin eosin staining; BALF was given cytological analysis; ELISA was used to detect IFN-γ levels in BALF; immunohistochemistry and Western Blot were used to detect IDO protein expression in lung tissue.Results:Asthma group: inflammatory cell infiltration, airway smooth muscle cell proliferation and lumen stenosis were obvious; intervention group: there were a small number of inflammatory cells infiltrating, there was airway smooth muscle cell proliferation, and lumen slightly narrowed; control group: there were no significant changes. The total number of cells, eosinophils and neutrophils in the BALF of asthma group were higher than those in the intervention group and the control group (P<0.05). The serum and BALF IFN-γ levels in asthma group were lower than those in intervention group and control group (P<0.05). The IDO gray value of lung tissue in asthma group was lower than that in control group and intervention group (P<0.05). IFN-γ level in serum was positively correlated with that in BALF(P<0.01), and expression of IDO protein in lung tissue was positively correlated with IFN-γ level in serum and BALF (P<0.01).Conclusion:There is a decrease in IDO protein expression in lung tissue of mice, which leads to deficiency and/or decrease of immune tolerance in vivo and promotes the development of bronchial asthma.

Key words: Asthma;Indoleamine 2, 3-dioxygenase;IFN-γ