Matrix Metalloproteinases-9 (MMPs-9) and -12 Are Upregulated in the Airways of Mice with Chronic Airway Inflammation and Remodeling

In the present study, we tried to develop a mouse model of chronic airway inflammation and remodeling induced by chronic exposure to antigen. Furthermore, the expressions of MMPs-9 and -12 were also investigated. BALB/c mice were sensitized and then repeatedly challenged with OVA every 3 days for 54 days. At the following day after the last challenge, of days 24, 39, and 54, histological changes of the airways were studied by hematoxylin-eosin and Masson's trichrome stains. The expressions of MMPs-9 and -12 were also measured by western blot. Persistent inflammatory cells infiltration and collagen deposition in the lung tissue were observed in repeatedly challenged mice. Furthermore, the expressions of MMPs-9 and -12 were increased in the airways after repeated antigen challenges. The severest inflammation was observed in the day-54 challenged group. These results suggest that MMPs-9 and -12 might be involved in the pathogenesis of chronic airway inflammation and remodeling induced by antigen exposure in mice.