The Effects Of Mycobacterium Vaccae Nebulization On The Prevention Of Bronchial Asthma And Respiratory Syncytial Virus Infection In Mice

Part 1 The effects of Mycobacterium vaccae nebulization on the prevention of bronchial asthma through the modulation of T cell subsets and TGF-β/smad signal pathway in miceObjective:To investigate the effects and mechanisms of Mycobacterium Vaccae nebulization on bronchial asthma.Methods:Twenty-four female BALB/C mice were randomized as normal control group(A),asthma control group(B)and prevention group(C).Asthmatic models were established by ovalbumin sensitization in group B and C.Group C were nebulized with Mycobacterium Vaccae once a day for consecutive 5 days while group B with PBS one month before asthmatic models were established.After asthmatic models were established,the non-invasive lung function were mesured,the bronchoalveolar lavage fluid(BALF)and lung tissue were harvested in all mice.Differential cell counts in BALF were performed;airway inflammation was observed by HE and PAS staining;the expression of TGF-β1、TβR1 Smadl and Smad7 was detected by immunohistochemistry staining;the percentages of γδTCR+CD3+,IL-13+CD3+,TGF-β+CD3+,IL-13+γδTCR+CD3+,TGF-β+γδTCR+CD3+ T lymphocytes were detected by flow cytometry.Results:The total cells counts,the proportion of Eosinophils and leukomonocytes,the expression of TGF-β1,TβR1 and Smad1,and the percentages of γδTCR+CD3+ and IL-13+CD3+T lymphocytes decreased in group C obviously compared with group B(P<0.01).The percentages of TGF-β+CD3+and IL-13+γδ8TCR+CD3+T lymphocytss·showed significant differences among 3 groups(P<0.05).Conclusion:Experimental doses of Mycobacterium Vaccae nebulization were contribute to the prevention of bronchial asthma in mice;the underlying mechanisms may be its modulation effects of T cell subsets and the suppressed expression of TGF-β1,TβR1 and Smad1 in TGF-β/Smad signaling pathways.Part two The effects of Mycobacterium vaccae nebulization on the prevention of respiratoy syncytial virus infection through the modulation of T cell subsets and TGF-β/smad signal pathway in miceObjective:To investigate the effects and mechanisms of Mycobacterium Vaccae nebulization on respiratiory syncytial virus infection.Methods:Twenty-four female BALB/C mice were randomized as normal group(A),RSV group(B)and prevention group(C).Group B and C were infected with RSV through nasal drip once a day for 3 days.Group C were nebulized with Mycobacterium Vaccae while Group B with PBS.once a day for 5 days one month before infection.Lung tissues were harvested 4 days after the last infection.The RSV infection condition were detected by electron microscope;airway inflammation was observed by HE staining;the expression of TGF-β1、T(3R1 was detected by immunohistochemistry staining;the percentages of γδTCR+CD3+,IL-13+CD3+,TGF-β+CD3+,IL-13+γδTCR+CD3+,and TGF-β+γδTCR+CD3+ T lymphocytes were detected by flow cytometry.Results:Group C showed milder RSV infection;decreased expression of TGF-β1,TβR1 and decreased percentages of γδTCR+CD3+,IL-13+CD3+,TGF-β+CD3+,IL-13+γδTCR+CD3+,and TGF-β+γδTCR+CD3+ T lymphocytes compared with group B.Conclusion:Experimental doses of Mycobacterium Vaccae nebulization were contribute to the prevention of respiratory syncytial virus in mice;the underlying mechanisms may be its modulation effects of T cell subsets and the suppressed expression of IL-13 and TGF-β1.