慢性烟曲霉暴露对哮喘大鼠气道重构及NF-κB/TGF-β1通路的影响

Effects of chronic exposure of aspergillus fumigatus on airway remodeling and signaling pathway of NF-κB/TGF-β1 in asthmatic rats

目的研究慢性烟曲霉暴露对哮喘大鼠气道重构及NF-κB/TGF-β1信号通路的影响。方法 24只Wister大鼠随机分为4组:空白对照组(A组),哮喘模型组(B组),0.9%氯化钠溶液组(C组,哮喘小鼠经鼻雾化吸入0.9%氯化钠溶液5周),烟曲霉暴露组(D组,哮喘小鼠经鼻雾化吸入烟曲霉5周),每组6只。B、C、D组采用卵清蛋白(OVA)致敏+OVA反复激发的方法建立大鼠哮喘模型。大鼠支气管肺泡灌洗液(BALF)涂片检测总细胞数及嗜酸性粒细胞、淋巴细胞和中性粒细胞百分比;肺组织切片HE染色观察大鼠肺组织病理改变并计算支气管周围胶原纤维面积(Wac)、气道管壁总面积(Wat)和管壁平滑肌面积(Wam),Masson染色观察气道黏膜下胶原沉积情况;采用Western blot检测肺组织中NF-κB、TGF-β1蛋白表达。结果与B、C组比较,D组大鼠肺组织出现黏膜褶皱增多,部分黏膜上皮脱落,黏膜下水肿,支气管管腔内炎性细胞增多,支气管黏膜下及支气管管壁血管周围炎性细胞浸润程度加重;与B、C组比较,D组总细胞计数、嗜酸性粒细胞百分比、淋巴细胞百分比、中性粒细胞百分比及Wat、Wam、Wac均明显升高(P<0.05);D组Ⅰ型胶原纤维、Ⅲ型胶原纤维平均IDO值和胶原纤维厚度明显大于B、C组(P<0.05),肺组织胶原沉积程度加重;D组NF-κB、TGF-β1蛋白表达高于B、C组(P<0.05)。结论慢性烟曲霉暴露促进嗜酸粒细胞等炎症细胞活化和胶原沉积,加重哮喘大鼠气道重构,其作用机制可能与持续激活NF-κB/TGF-β1信号通路有关。

Objective To explore the effects of chronic exposure of aspergillus fumigatus on airway remodeling and signaling pathway of NF-κB/TGF-β1 in asthmatic rats.Methods Twenty-four Wister rats were randomly divided into four groups:control group(group A,n=6),asthmatic model group(group B,n=6),saline group(group C,n=6) and aspergillus fumigatus exposure group(group D,n=6).The rats in group C and group D were given aerosol inhalation of 0.9% sodium chloride solution and aspergillus fumigatus for five days,respectively.The asthmatic model was established in group B,group C and group D by ovalbumin(OVA)+ repeated stimulation of OVA.Bronchoalveolar lavage fluid(BALF) smears were used to detect the total number of cells and the percentages of eosinophils,lymphocytes and neutrophils.Moreover,HE staining of lung tissue sections were used to observe the pathological change of lung tissues.Furthermore,the area of peribronchial collagen fiber(Wac),total area of airway wall(Wat) and the smooth muscle area of tubular wall(Wam) were calculated.In addition,Western Blot was used to detect the expressions of NF-κB and TGF-β1 in lung tissues.Results As compared with those in group B and group C,the pulmonary tissues of the rats in group D showed increased mucosal folds,submucosal edema,inflammatory cells in bronchial lumen,perivascular inflammatory cell infiltration of the bronchial submucosa and around the bronchial wall vessels as well as partial exfoliation of mucosal epithelial.Moreover,the total number of cells,the percentages of eosinophils,lymphocytes and neutrophils,Wat,Wam,and Wac in group D were increased significantly(P<0.05).Furthermore,the average IDO values of typeⅠand type Ⅲ collagen fibrils as well as the collagen fiber thickness in group D were significantly higher than those in group B and group C(P<0.05).And the collagen deposition in lung tissue was aggravated.In addition,the expressions of NF-κB and TGF-β1 in group D were higher than those in group B and group C(P<0.05).Conclusion Chronic exposure of aspergillus fumigatus can promote the activation of inflammatory cells,such as eosinophils and collagen deposition,and promote collagen deposition,aggravate airway remodeling in asthmatic rats.Its mechanism may be related to the continuous activation of the signaling pathway of NF-κB/TGF-β1.