Influence of dexamethasone on airway remodeling in murine model of chronic asthma

Objective To observe the changes of airway inflammation and remodeling in a murine model of chronic asthma and effects of dexamethasone(DXM) on it.Methods BALB/c mice were sensitized and repeatedly challenged with ovalbumin.Pathological slides were prepared stained with hematoxylin-eosin.WAm Smooth muscle area,WAmuc mucous areaand WAi Outer wall area of the airway were measured and standardized by Pbm(Basement membrane perimeter).The distribution and the area of type Ⅰand type Ⅲcollagen in the lung tissue were determined using a sirius red-polarizing microscopy morphometry method.Expression of matrix metalloprotease-9(MMP-9) and tissue inhibitor of metalloproteinase-1(TIMP-1)were detected by immunohistochemistry.Results(1)WAm/Pbm,WAmuc/Pbm and WAi/Pbm increased greater in both asthma group and DXM treated group than in control group(P0.05),and it was greater in asthma group than in DXM treated group(P0.05).(2)Collagen deposition in asthma group increased more than in DXM treated group(P0.05).(3)There was a significantly increase of MMP-9 and TIMP-1 expression level in(asthma) group and DXM treated group than in control group(P0.05),and it was much higher in asthma group than in DXM treated group(P0.05).Conclusion Airway remodeling could occur in the chronic asthma.Early intervention with steroid might partially inhibits its process via higher expression of MMP-9/TIMP-1 in chronic asthma.