Neutralization of stratum corneum accelerates the progress from atopic dermatitis to asthma-like lesion in flaky tail mice treated by house dust mite allergen

Background: A disrupted skin barrier of atopic dermatitis (AD) permits easier penetration and sensitization of external allergens and then induces the development of asthma and allergic rhinitis, so called the ‘atopic march’. Maintenance of normal acidity in the stratum corneum (SC) is an important factor for normal skin barrier function. Elevation of SC pH accompanied by the increase of serine protease activity and TSLP expression provokes skin inflammation. Objective: We determined whether the neutralized SC environment can accelerate airway inflammation more easily in flaky tail mice, a representative AD murine model with congenital skin barrier abnormality, after the exposure of house dust mite (HDM). Methods: Dermatofagoides pteronyssinus (Dp), a HDM was applied on the dorsal skin of flaky tail mice twice a week, which accompanied by the application of neutral cream (pH 7.4) and acidic cream (pH 2.8) twice a day for 6 weeks. Intranasal inhalation of Dp was done daily during last 3 days. Gross findings, functional study for skin barrier, blood sampling, bronchoalveolar lavage and biopsies of skin and lung were done at 24 h after last treatment. Results: Repeated topical applications followed by intranasal inhalations of Dp to flaky tail mice made the respiratory allergic inflammation as well as the AD-like skin lesion. Accompanying neutral cream treatment accelerated or aggravated the allergic inflammation in the respiratory system as well as the skin. Conclusion: Atopic march-like progress from AD to asthma-like lesion can be observed in flaky tail mice after topical and intranasal application of HDM, and the neutralization of SC can accelerate or aggravate it.