Airway Remodeling in Mice with Experimentally Induced Airway Allergy

Kim, Hyo Seon; Kim, Dong Hyun; Park, Jae Yong; Choi, Jin Woong; Kim, Yong Min; Rha, Ki Sang

Abstract

BACKGROUND AND OBJECTIVES: Allergic rhinitis and asthma display many similarities in their epithelial and inflammatory responses to allergens. However, one notable difference is that disruption and desquamation of the epithelium is a characteristic feature of asthma, whereas, in allergic rhinitis, the epithelium is intact. Airway remodeling is a well-recognized feature among patients with chronic asthma but not in allergic rhinitis. The purpose of this study is to investigate the airway remodeling in mice with experimentally induced airway allergy.
SUBJECTS AND METHOD
Male BALB/c mice were systemically sensitized with ovalbumin mixed with aluminum hydroxide gel solution and were challenged with aerosols of ovalbumin. Then, the mice were chronically exposed to aerosols of ovalbumin for 5 weeks to 10 weeks. After the last exposure, bronchoalveolar lavage fluid (BALF) and nasal lavage fluid (NLF) were collected. Next, the number of inflammatory cells and the concentrations of IL-5, IL-13, TGF-beta and IFN-gamma in BALF and NLF were measured. Finally, nasal cavity and lung specimen were obtained to evaluate the subepithelial fibrosis by trichrome stain and the expression of MMP-9 and TIMP-1 by immunohistochemical stain.
RESULTS
The concentrations of IL-5, IL-13, TGF-beta within the BALF & NLF were found to have significantly increased in the 10-week exposed group compared with the control group. The expression of MMP-9, TIMP-1 and subepithelial fibrosis in the lung tissue were also found to have significantly increased in the 10-week exposed group comparative to that of the control group. But the expression of MMP-9, TIMP-1 and subepithelial fibrosis in the nasal mucosa were not prominent in the 10-week exposed group compared with the control group.
CONCLUSION
The results suggest that airway remodeling may be induced by repeated allergen exposure in allergic rhinitis but the structural changes of the nasal mucosa by remodeling process are less prominent compared with the lung tissue.