AAD decreased the collagen deposition in the model of chronic asthma. Lung sections were stained with Masson trichrome to detect collagen deposition around airways. Representative photomicrographs of collagen deposition in different group are shown in (A). White arrows indicate areas with clear collagen deposition. Quantitatively, collagen area on the basal membrane of airway was analyzed and the result was expressed as collagen staining area per micrometer length of basement membrane of bronchioles (B). Data are presented as means ± SE for 8–10 mice per group. H + OVA: OVA challenged and treated with high dose AAD, L + OVA: OVA challenged and treated with low dose AAD. #p < 0.05 compared with NS. *P < 0.05 compared with OVA group.