雾化吸入灭活草分枝杆菌降低哮喘小鼠核因子κB及细胞间黏附分子1的表达

 目的:研究雾化吸入灭活草分枝杆菌对支气管哮喘小鼠气道炎症，以及哮喘肺组织中核因子κB(NF-κB)、细胞间黏附分子1(ICAM-1)和血管细胞黏附分子1(VCAM-1)的影响，探讨雾化吸入灭活草分枝杆菌防治哮喘的机制。方法:将24只雄性BALB/c小鼠按随机数字表法分为3组，每组8只：正常对照组（A）、哮喘模型组（B）和治疗组（C）。以鸡卵清蛋白致敏制造小鼠支气管哮喘模型。C组在激发后给予雾化吸入灭活草分枝杆菌治疗5 d，每天1次。各组动物处死后提取肺组织和支气管肺泡灌洗液（BALF）。进行病理HE染色及AB-PAS染色观察气道炎症浸润及黏液分泌情况，并行病理半定量分析。对BALF中炎症细胞进行分类计数。实时荧光定量PCR检测肺组织NF-κB、ICAM-1和VCAM-1的mRNA表达水平。结果:治疗组嗜酸性粒细胞比例低于模型组(P<0.05)，气道炎症病变及黏液分泌情况较模型组减轻(P<0.05, P<0.01)。哮喘模型组的肺组织中NF-κB mRNA含量与正常组相比显著升高(P<0.01)，而治疗组肺组织中的NF-κB mRNA 含量明显低于模型组(P<0.05)；模型组的ICAM-1 mRNA 水平比正常组高(P<0.05)，但治疗后明显降低(P<0.01)；VCAM-1的 mRNA水平在各组间无显著差异。相关性检验发现小鼠肺组织中VCAM-1的mRNA与ICAM-1的mRNA呈明显正相关(r=0.84，P<0.01)，但NF-κB的mRNA与ICAM-1的mRNA、VCAM-1的mRNA无明显相关性(均P>0.05)。结论:雾化吸入草分枝杆菌对支气管哮喘小鼠气道炎症及黏液分泌有抑制作用；NF-κB参与哮喘发病过程，雾化吸入灭活草分枝杆菌降低哮喘小鼠的NF-κB水平。同时雾化吸入灭活草分枝杆菌可降低黏附分子尤其是ICAM-1的表达，是其控制炎症的另一个重要机制。

Inhalation of inactivated Mycobacterium phlei down-regulates expression of nuclear factor-kappa B and intercellular adhesion molecule-1 in asthmatic mice

AIM:To investigate the effect of inhalation of inactivated Mycobacte-rium phlei on the expression of nuclear factor-kappa B (NF-κB), intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1 in the lung tissues of asthmatic mice. METHODS:Male BALB/c mice (n=24) were randomly divided into normal control group (A), asthmatic model group (B), and inactivated Mycobacterium phlei inhalation group (C). Asthmatic model was made by inhalation of chicken ovalbumin. The mice in group C were treated with inactivated Mycobacterium phlei for 5 d. The lung tissues and bronchoalveolar lavage fluid (BALF) were harvested. HE and AB-PAS staining were used to measure the lung inflammation and mucus production. The inflammatory cells in the BALF were counted. The mRNA expression of NF-κB, ICAM-1 and VCAM-1 was detected by real-time fluorescence quantitative PCR. RESULTS:Mycobacterium phlei treatment alleviated lung inflammation, attenuated mucus production, and reduced the percentage of eosinophils in the BALF. The mRNA levels of NF-κB and ICAM-1 were significantly decreased after treated with Mycobacterium phlei. However, no significant difference of VCAM-1 mRNA expression was found before and after treatment. The correlation between NF-κB mRNA and ICAM-1 mRNA, and between NF-κB mRNA and VCAM-1 mRNA was not found. CONCLUSION:Inhalation of inactivated Mycobacterium phlei attenuates asthmatic airway inflammation. NF-κB participates in the pathogenesis of asthma. NF-κB signal pathway may be associated with the therapeutic mechanism. Another important mechanism is the reduction of adhesion molecule expression.