Enhancement of gelatinase activity during development of subepithelial fibrosis in a murine model of asthma
Article first published online: 8 MAY 2003
Clinical & Experimental Allergy
Volume 33, Issue 5, pages 696–704, May 2003
How to Cite
Corbel, M., Caulet-Maugendre, S., Germain, N., Lagente, V. and Boichot, E. (2003), Enhancement of gelatinase activity during development of subepithelial fibrosis in a murine model of asthma. Clinical & Experimental Allergy, 33: 696–704. doi: 10.1046/j.1365-2222.2003.01581.x
- Issue published online: 8 MAY 2003
- Article first published online: 8 MAY 2003
- Submitted 17 December 2001; revised 2 August 2002; accepted 27 September 2002
- tissue inhibitor of matrix metalloproteinase
Background Chronic asthma is characterized by inflammatory cell infiltration and tissue remodelling leading to subepithelial fibrosis. Metalloproteinases (MMPs) are involved in degradation of extracellular matrix in most chronic inflammatory diseases.
Objective The aim of this study was to investigate the expression of MMPs in the development of inflammatory processes associated or not with the concomitant development of subepithelial fibrosis in an experimental model of asthma.
Methods Sensitized BP2 mice were challenged with ovalbumin (OA) every 2 weeks during 8 months. Several mice were removed once a month and bronchoalveolar lavages (BAL) or lung biopsies were performed.
Results Lung sections stained with picrosirius and hydroxyproline measurements showed a significant collagen deposition after 16 weeks of OA challenge, demonstrating the development of subepithelial fibrosis. Pulmonary inflammation was present from the first OA challenge and was consistent throughout the 8 months of the study. Moreover, an up-regulation and activation of MMP-9 and, to a less extent, MMP-2 were observed in BAL fluid from challenged mice. The level of tissue inhibitor of metalloproteinases (TIMP)-1 increased after 12 weeks of OA challenge vs. control mice.
Conclusion This study reveals that a decrease in the activation of the MMP-9 due to the increase in TIMP-1, could contribute to excessive collagen deposition following repeated antigen challenge in sensitized mice.