A study on the effects of TGF-β1 on the airway wall remodeling in asthma rat models

Objective To investigate the pathological features of airway remodeling, ie.the smooth muscle thickening and collagen deposition in asthmatic rat model, to evaluate the modulating effects of corticosteroid and TGF-β1 on airway remodeling.Methods A rat model of asthma was established by sensitized with ovalbumin conjuncted with Al(OH)3 and Bordetelk Pertussis bacilli, then challenged with repeated expossure to aerosolized ovalbumin. Rats were randomly divided into the control,asthmatic, and steroids group. The thickness of the smooth muscle (WAm) of intrapulmonary bronchi was measured by image analysis system, the collagen stained with carbazotic acid-Sirius Red were observed by po-larimicroscop.and the thickness of collagen in bronchi was measured by image analyzer (Image-pro plus). The expression and localization of TGF-β1 in bronchi and lung tissues were observed by immunohistoche-mistry.Results 1. After repeated allergen exposure for one week, airway wall thickening and smooth muscle hyperplasia were demonstrated in rat bronchus. After challenged for two weeks airway remodeling was more remarkable, while expression levels of TGF-β1 in the epithelial cells of bronchi were significantly higher than those of control group. 2. Collagen deposition in rat airway was more significant in those challenged for 2 weeks than those for 1 week. 3.Compared with asthmatic group,there was mild inflammation and collagen deposition in steroids-treated group while no significant differences between steroids group and control were found.Conclusions 1.Repeated exposure of allergen induced airway inflammation and remodeling. 2. TGF-β1 may play an important role in airway wall remodeling.3.Steroids intervention could inhibit airway inflammation and remodeling.