Effect of dexamethasone on airway remodeling and expression of mast and IL-10 in asthmatic rats

Objective To investigate the influence of dexamethasone on airway remodeling and lung mast cells,IL-10 in asthmatic rats. To discuss the mechanism of dexamethasone on airway inflammation and airway remodeling,to provide the experimental evidence for clinical treatments. Methods Rats were sensitized and challenged with ovalbumin(OVA) to establish the asthmatic model. Thirty SD rats were randomly divided into three groups:control group(A),asthma group(B),dexamethasone treatment group(C),10 rats in each group. The changes of airway wall morphologic parameter were determined using a computer assisted image analysis system. The paraffin embedded sections of lung tissue underwent hemotoxylin and eosin(HE) staining and the lung pathological changes were observed.The expression of mast cells,IL-10 in lung tissues were detected by immunohistochemistry. Results After repeated allergen challenge,obvious infiltration of inflammatory cells and proliferation of goblet cells and smooth muscle were demonstrated in asthmatic rats. Expression levels of IL-10 in the epithelial cells of bronchi decreased obviously than in control animals. Compared with the asthmatic group,there was mild inflammation,smooth muscle hyperplasia,mucus secretion in dexamethasone group. Expression levels of IL-10 increased obviously,and there were significantly difference than that in asthmatic animals. ConclusionRepeated exposure of allergen induces airway inflammation and remodeling. Mast cell,IL-10 plays an important role in airway remodeling. Dexamethasone may restrain the increase of thickness of total airway wall and smooth muscle by inhibiting mast cell degranulation,increasing IL-10 expression in lung tissue.