A Novel Atopic Dermatitis Model Induced by Topical Application with Dermatophagoides Farinae Extract in NCNga Mice

Background: Atopic dermatitis is a chronically relapsing inflammatory skin disease. Animal models induced by relevant allergens play a very important role in the elucidation of the disease. The patients with atopic der-matitis are highly sensitized with mite allergens such as Dermatophagoides farinae (Df). Therefore, in the pre-sent study, we tried to develop a novel model for atopic dermatitis by repeated application with Df extract oint-ment. Methods: Df extract ointment was repeatedly applied to the back of NCNga mice together with barrier disrup-tion. Atopic dermatitis-like skin lesions were evaluated by dermatitis scores, skin histology and immunological parameters. The effect of corticosteroid and calcineurin inhibitor was also examined. Results: Repeated application of Df extract ointment caused rapid increase in dermatitis scores. Clinical (skin dryness, erythema, edema and erosion) and histological symptoms (dermal and epidermal thickening, hyperk-eratosis, parakeratosis and inflammatory cell infiltration) in this model were very similar to those in human atopic dermatitis. Serum total and Df-specific IgE levels were elevated in this model compared with normal mice, and draining lymph node cells isolated from the mice that exhibited dermatitis produced significant amounts of interleukin-5, interleukin-13 and interferon-γ after re-stimulation with Df. Furthermore, current first-line drugs for the treatment of human atopic dermatitis, corticosteroid and tacrolimus ointments, were effective against the clinical and histological symptoms in this model. Conclusions: These results suggest that the model we have established is useful for not only elucidating the pathogenesis of atopic dermatitis but also for evaluating therapeutic agents