Oral administration of bepotastine besilate suppressed scratching behavior of atopic dermatitis model NC/Nga mice.

BACKGROUND: Pruritus is the most severe problem in atopic dermatitis. Even though its mechanism is still not fully understood, antihistamines have been prescribed for atopic dermatitis.

OBJECTIVE: To evaluate the effect of antihistamine on atopic dermatitis, we analyzed the scratching behavior in atopic dermatitis model NC/Nga mice.

METHODS: BALB/c mice, in which scratching behavior was induced by intradermal injection of compound 48/80 (100 microg/100 microl/mouse), and NC/Nga mice, housed in a conventional environment and having developed spontaneous eczematous regions, were monitored with a SCLABA system after oral administration of bepotastine besilate. The number of eosinophils in the ear skin and the serum leukotriene B(4) (LTB(4)) levels were also evaluated.

RESULTS: Bepotastine at doses of 3 and 10 mg/kg effectively inhibited the compound 48/80-induced scratching behavior of BALB/c mice 1 h after oral administration, comparable with the blood T(max), which was reached within 0.8-1.6 h in humans. Bepotastine also significantly inhibited the scratching behavior of NC/Nga mice 1 h after oral administration. Even though 10 mg/kg bepotastine could not influence the number of tissue eosinophils, it effectively suppressed the serum LTB(4) levels, just comparable with the suppression of scratch behavior of NC/Nga mice.

CONCLUSION: Bepotastin effectively suppressed the scratch behavior of atopic dermatitis model mice, which may not simply be explained by the suppression of histamine but also by the suppression of other mediators like LTB(4). Bepotastine could be useful in the treatment of pruritus, especially early after oral administration.