Observation Of The Prevention Effects Of Inhaled Mycobacterium Vaccae In Asthmatic Mice

Objective To study the prevention effects of nebulizing inhaled Mycobacterium vaccae for asthmatic mice, and study the mechanism of the prevention effects.Methods Fourty female BALB/C mice were randomized into normal control, asthma control, three dosage prevention groups (pre-22.5ug group,pre-45ug group, pre-67.5ug group).Two weeks before building asthma models,the prevention groups nebulized inhaled Mycobacterium vaccae regularly once a day for 5 consecutive days. DO the detection of noninvasive lung function in 24 hours after the last time inhaled challenge with OVA. Collect the blood,bronchoalveolar lavage fluid (BALF) and lung tissue.Use HE staining and AB-PAS staining to observe the lung pathological changes. Luminex was used for determining the concentrations of cytokine interleukin-4(IL-4), IL-5,IFN-?and IL-17A in BALF and serum. Measure the expression level of IL-4,IL-5, IFN-?, IL-17A and ??-T cell in lung tissue with Immunoistochemical analysis.Results Compared with asthma control, the prevention groups showed significantly lower airway responsiveness, less airway inflammation infiltration ;showed significantly lower expression level of IL-4, IL-5, IL-17A, y8-TCR and higher expression level of IFN-y in lung tissue(P<0.05).. Between the prevention groups, pre-67.5ug group showed significantly stronger prevention effects than pre-22.5ug group?pre-45ug group (P<0.05). The expression level of IL-17A showed negatively correlation with dosage (P<0.05).Conclusion Nebulizing inhaled Mycobacterium vaccae for asthmatic mice have prevention effects, in the three dosage group , effects of pre-67.5ug group is the most significant. The mechanism of this prevention effects may be associated with the suppression of the y8-T cell aggregation in lung tissue, the Thl/Th2 imbalance and the Th17 dominant response.