Development of Aspergillus fumigatus-induced chronic atopic dermatitis mouse model

Abstract

Purpose: Atopic dermatitis (AD) is the most common chronic and relapsing inflammatory skin disease with skin barrier defects and altered immune responses. Chronic inflammation leads to irreversible fibrosis in the skin and there is no treatment to completely abolish the inflammation and fibrosis. To prevent or treat the chronic process of AD, it is necessary to develop a murine model of AD that reflects the chronic process to identify the mechanism. The aims of this study were to develop a chronic AD model with a crude extract Aspergillus fumigatus (Af) antigen. Methods: We applied Af extract (40 μg) epicutaneously to the dorsal skin of BALB/c mice for 5 consecutive days per week during a period of 5 weeks for a chronic AD model, and 5 consecutive days repeatedly with 2 weeks interval for an acute AD model. Results: The clinical score and transepidermal water loss were more increased in the chronic AD model than in the acute AD model. Histologic findings showed that more increased epidermal thickness, neutrophil infiltration and hyperkeratosis in the chronic model than in the acute model. Skin fibrosis was more prominent in the chronic model than in the acute model. The mRNA expression lev els of transforming growth factor (TGF)-β, thymic stromal lymphopoietin, and interleukin-33 were increased in the skin of the chronic model compared to the acute model. The levels of total IgE, Af-specific IgE, IgG1, and IgG2a were significantly increased in the chronic model compared to controls. Conclusion: The Af-induced chronic AD model showed prominent fibrosis and increased TGF-β expression in the skin, which sug gests that these models may be useful in the research for the mechanism of the chronic process in AD. (Allergy Asthma Respir Dis 2019;7:150-157)