Establishment of allergic dermatitis in NC/Nga mice as a model for severe atopic dermatitis.

Mite antigen has been suggested to play important roles in the onset and/or development of atopic dermatitis, and mite antigen-induced dermatitis models appear beneficial for the basic study of atopic dermatitis. In the present study therefore, we attempted to establish an allergic dermatitis model in mice using Dermatophagoides farinae crude extract as an antigen. Mite antigen solution at a concentration of 1 or 10 mg/ml was painted 5 times repeatedly at an interval of 7 d onto the ear of NC/Nga or BALB/c mice with or without simultaneous tape-stripping. Apparent biphasic ear swelling was observed after the 4th and 5th antigen applications in both strains of mice treated with 10 mg/ml of antigen solution. Thickening of the epidermis, fibrosis of the dermis, and the accumulation of inflammatory cells were also observed after the 5th application. The inflammatory changes were more evident in NC/Nga mice than in BALB/c mice and potentiated by tape-stripping. The ear swelling was accompanied by increased serum IgE, increased expression of interleukin-4 mRNA and decreased expression of interferon-gamma mRNA in cervical lymph nodes and ears. These results indicate that ear swelling caused by repeated mite antigen application with simultaneous tape-stripping has a Th2-dominant background and that the inflammatory responses are expressed more potently in NC/Nga mice than in BALB/c mice. The dermatitis caused by mite antigen in NC/Nga mice appears to be a useful model for the basic study of atopic dermatitis.