Mycobacterium vaccae nebulization imparted protective effect against allergic asthma in a mouse model. The TGF-β/Smad signal transduction pathway plays an important role in allergic bronchial asthma. However, the effect of M. vaccae nebulization on the TGF-β/Smad signal transduction pathway in mouse models of allergic asthma remains unclear. This study investigated the preventive effect of M. vaccae nebulization during bronchial asthma in a mouse model and elucidate the implication of TGF-β/Smad signal transduction pathway in the process. In total, 24 female Balb/c mice were randomized to normal control (group A), asthma control (group B), and M. vaccae nebulization (group C) groups. Both groups B and C were sensitized using ovalbumin for establishment of the asthmatic model; group A received phosphate-buffered solution. Prior to the establishment of asthma, Group C was nebulized with M. vaccae. Airway responsiveness was measured in all the groups, using a noninvasive lung function machine before and 24 h after establishment of the asthmatic model. The animals were then harvested, and bronchoalveolar lavage fluid (BALF) and lung tissue were collected. The total cell counts in BALF was estimated. Protein expression of TGF-β1, TβR1, Smad1, and Smad7 was detected by immunohistochemistry. The population of CD3+γδT, IL-13+CD3+T, TGF-β+CD3+T, IL-13+CD3+γδT, and TGF-β+ CD3+ γδT cells were detected by flow cytometry. One-way analysis of variance for within-group comparisons, the least significant difference t-test or Student–Newman–Keuls test for intergroup comparisons, and the nonparametric rank sum test for analysis of airway inflammation scores were used in the study. The eosinophil count; protein expression of TGF-β1, TβR1, and Smad1; and percentages of CD3+γδT and IL-13+CD3+T cells were significantly lower in the M. vaccae nebulization group than in the asthma control group (P < 0.01). There were significant intergroup differences in the percentages of TGF-β+CD3+T and IL-13+CD3+γδT cells (P < 0.05). Mycobacterium vaccae nebulization could confer protection against allergic bronchial asthma by reducing airway responsiveness and alleviating airway inflammation in mice. The underlying mechanism might be attributed its effect on the deregulated expression of TGF-β1, TβR1, Smad1, and Smad7 of the TGF-β/Smad signal transduction pathway.

中文翻译：

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吸入雾化的母牛分枝杆菌可通过调节 TGF-β/Smad 信号转导通路预防小鼠过敏性支气管哮喘。

母牛分枝杆菌雾化对小鼠模型的过敏性哮喘具有保护作用。TGF-β/Smad 信号转导通路在过敏性支气管哮喘中起重要作用。然而，母牛分枝杆菌雾化对过敏性哮喘小鼠模型中 TGF-β/Smad 信号转导通路的影响仍不清楚。本研究在小鼠模型中调查了母牛分枝杆菌雾化对支气管哮喘的预防作用，并阐明了该过程中 TGF-β/Smad 信号转导通路的意义。总共将 24 只雌性 Balb/c 小鼠随机分为正常对照组（A 组）、哮喘对照组（B 组）和母牛分枝杆菌雾化（C 组）组。B、C组均采用卵清蛋白致敏建立哮喘模型；A组接受磷酸盐缓冲液。在形成哮喘之前，C 组用母牛分枝杆菌雾化。在建立哮喘模型之前和之后 24 小时，使用无创肺功能机测量所有组的气道反应性。然后收获动物，收集支气管肺泡灌洗液（BALF）和肺组织。估计了 BALF 中的总细胞计数。免疫组化检测TGF-β1、TβR1、Smad1和Smad7的蛋白表达。流式细胞仪检测CD3+γδT、IL-13+CD3+T、TGF-β+CD3+T、IL-13+CD3+γδT和TGF-β+CD3+γδT细胞群。研究中使用了用于组内比较的单向方差分析、用于组间比较的最小显着性差异 t 检验或 Student-Newman-Keuls 检验以及用于分析气道炎症评分的非参数秩和检验。嗜酸性粒细胞计数；TGF-β1、TβR1 和 Smad1 的蛋白表达；母牛分枝杆菌雾化组CD3+γδT和IL-13+CD3+T细胞的百分比显着低于哮喘对照组（P < 0.01）。TGF-β+CD3+T和IL-13+CD3+γδT细胞百分比有显着组间差异（P < 0.05）。母牛分枝杆菌雾化可通过降低小鼠气道反应性和减轻气道炎症来预防过敏性支气管哮喘。潜在机制可能归因于其对 TGF-β/Smad 信号转导通路 TGF-β1、TβR1、Smad1 和 Smad7 表达失调的影响。母牛雾化组优于哮喘对照组（P < 0.01）。TGF-β+CD3+T和IL-13+CD3+γδT细胞百分比有显着组间差异（P < 0.05）。母牛分枝杆菌雾化可通过降低小鼠气道反应性和减轻气道炎症来预防过敏性支气管哮喘。潜在机制可能归因于其对 TGF-β/Smad 信号转导通路 TGF-β1、TβR1、Smad1 和 Smad7 表达失调的影响。母牛雾化组优于哮喘对照组（P < 0.01）。TGF-β+CD3+T和IL-13+CD3+γδT细胞百分比有显着组间差异（P < 0.05）。母牛分枝杆菌雾化可通过降低小鼠气道反应性和减轻气道炎症来预防过敏性支气管哮喘。潜在机制可能归因于其对 TGF-β/Smad 信号转导通路 TGF-β1、TβR1、Smad1 和 Smad7 表达失调的影响。母牛分枝杆菌雾化可通过降低小鼠气道反应性和减轻气道炎症来预防过敏性支气管哮喘。潜在机制可能归因于其对 TGF-β/Smad 信号转导通路 TGF-β1、TβR1、Smad1 和 Smad7 表达失调的影响。母牛分枝杆菌雾化可通过降低小鼠气道反应性和减轻气道炎症来预防过敏性支气管哮喘。潜在机制可能归因于其对 TGF-β/Smad 信号转导通路 TGF-β1、TβR1、Smad1 和 Smad7 表达失调的影响。