抄録
We reported that mast cells in the ear painted with picryl chloride (PiCl) of NC/Nga mice, an animal model of atopic dermatitis, increased sequentially, and mast cell surface antigen-1 (MASA-1) was involved in the pathogenesis of atopic dermatitis. Interestingly, the non-painted ear in the PiCl-treated mice showed an increased thickness. In this study, we investigated the kinetics of mast cells in the non-painted ear of PiCl-treated mice. The tissue histamine levels in the painted ear, non-painted ear of PiCl-treated mice, and non-painted ear of PiCl non-treated mice (control) were 123±10.3μg/g tissue (p<0.05), 95.3 ±18.0μg/g tissue, and 65.8±18.3μg/g tissue, respectively. The number of mast cells in the non-painted ear of PiCl-treated mice, assayed by toluidine blue staining, increased in comparison with the control. Moreover, the number of MASA-1 positive cells was increased not only in the PiCl painted ear but also in the non-painted contrary ear. Since MASA-1 positive cells are considered to be activated mast cells, these results suggest that such cells may induce hyperplasia of the non-painted ear of PiCl-treated mice. Substance P (SP) is one of the most potent endogenous pruritogenic peptides. Ohmura et al. reported that tachykinin NK1 receptor antagonist inhibited SP-induced scratching behavior. SP is known as a potent mast cell activator. Thus, the present findings suggest that mast cells, activated by endogenous stimulator such as SP, may play a crucial role in the systemic response of atopic dermatitis. [Jpn J Physiol 55 Suppl:S234 (2005)]
