Effect And Possible Mechanisms Of IL-17A Expression In The Lung Of Asthmatic Mice Of BCG Intervention

Background:The bronchial asthma is a chronic inflammatory airway disease.It involved in inflammatory cells and cellular components.The eosinophilic cells infiltration is the basic characteristics; some asthma patients are more neutrophil infiltration than eosinophilic cells.The studies have shown that severe and glucocorticoid-dependent refractory patients with bronchial asthma existed in neutrophils increasing in induced sputum and bronchoalveolar lavage fluid (BALF), and mucous tissue.IL-17A has a strong chemotactic role on neutrophil cells, increased significantly neutrophil-raising and activation in the respiratory tract,aggravated acute bronchial asthma and chronic bronchial asthma acute attack. (BCG) as a live attenuated tuberculosis vaccine, has a strong non-specific immune stimulation. It can correct the Thl/Th2 cytokine balance, So that Th2-type immune response reverse to Thl-type immune response, reduced airway inflammation. BCG maybe correct the Thl/Th2 cytokine balance, increasing Thl-type immune response to increase IFN-γand to reduce IL-17A in the lung tissue, reducing neutrophil-raising and activation to reduce airway inflammation, which have not seen the reported. Objective:To establish a mouse asthma model, mice were give to the prevention of BCG vaccination, observing the effect of IL-17A expression in the lung tissue of asthmatic mice of BCG intervention, and to explore its possible mechanisms.Methods:The 2-month-old of 24 male Kunming mice were randomly divided into three groups:normal control group (A group), asthma model group (B group), BCG intervention group (C group).We establish the asthma model of mice by sensitizing with ovalbumin. Observing the general situation of the three groups mice;Detected cell types in BALF,analyzed pathological changes in lung;Detected the IL-17A and IFN-γconcentration of lung tissue by used enzyme-linked immunosorbent assay (ELISA).Results:1.BALF examination revealed:Number of total leukocytes and number of neutrophils and eosinophils and lymphocytes in BALF of asthma model group (B group) were significantly higher than normal control group (A group) (P<0.01). Number of total leukocytes and number of neutrophils and eosinophils in BALF of BCG intervention group (C group) were significantly lower than asthma model group (B group), (P<0.01). 2.Pathological examination revealed:Pathological analysis of the lung showed that normal control group (A group) almost no inflammatory cell infiltration, and asthma model group (B group)a large number of inflammatory cells infiltration and was significantly higher than normal control group (A group) (P<0.01).BCG intervention group(C group) had lower inflammatory cells infiltration than asthma model group (B group)(P<0.01),but still higher than normal control group (A group)(P<0.01)3.Enzyme-linked immunosorbent assay results revealed:Concentrations of IFN-γof lung of asthma group (B group) was significantly lower than normal control group (A group), and concentrations of IL-17A of lung of asthma group (B group)was significantly higher than normal control group (A group), (P all<0.01). Concentrations of IFN-γof lung of BCG intervention group (C group) was lower than normal control group (A group), Concentrations of IL-17A of lung of BCG intervention group (C group) was higher than normal control group (A group), (P all<0.05).Concentrations of IFN-y of lung of asthma group (B group) was lower than BCG intervention group (C group), (P<0.01);Concentrations of IL-17A of lung of asthma group (B group) was higher than BCG intervention group (C group), (P<0.05). The differences were statistically significant.4.The analysis of correlation indicated: Concentrations of IFN-γwere significantly negatively correlation with airway inflammation and BALF number of neutrophils in asthma model group (B group),(P<0.01),Concentrations of IL-17A were significantly positive correlation with airway inflammation and BALF number of neutrophils in asthma model group(B group)(P<0.05,P< 0.01);Concentrations of IFN-γwas significantly negatively correlation with concentrations of IL-17A in asthma model group (B group),(P< 0.01).Conclusion1.Concentration of IL-17A of lung significantly increased and positive correlated with airway inflammation, Concentrations of IFN-γof lung was significantly lower and was negatively correlation with airway inflammation in a mouse model of bronchial asthma.2.Intervention of BCG increased concentrations of IFN-γand reduced concentrations of IL-17A in the lung tissue of asthmatic mice, reduced number of total leukocytes and number of neutrophils and eosinophils in BALF.3.BCG maybe increase IFN-γby increasing Thl-type immune respose to reduce IL-17A in the lung tissue, to reduce neutrophil-raised and activation, so as to reduce airway inflammation.