Adhesive explant culture of allergic nasal mucosa: effect of emedastine difumarate, an anti-allergic drug.
Allergic reaction of the nose comprises of an immediate and a late reaction. To evaluate nasal allergic reactions, many experiments have been performed by investigators. In this study, we performed a new tissue culture technique (adhesive explant culture) to analyze the migration of cells into the culture medium from the cultured allergic nasal mucosa in response to an allergen. Basophilic cells (mast cells and basophils) and eosinophils, which were released into the culture medium after the allergen challenge, were evaluated by the analysis of histamine and eosinophil cationic protein (ECP) content in the culture medium. Histamine and basophilic cells in the culture medium were more abundant in the immediate phase (within 30 min) after challenge than in the late phase (from 30 min to 10 hr). On the other hand, ECP and eosinophils in the culture medium were more abundant in the late phase than in the immediate phase. The increase of histamine content in both phases were not inhibited by pre-treatment of emedastine difumarate (EME), an anti-allergic drug. However, the increase of ECP in the late phase was inhibited by pre-treatment with EME. Moreover, the number of EG2-positive cells was also decreased by pre-treatment with EME. These results suggest that EME might lower the activation of eosinophils in the late phase of the allergic reaction. The present study also indicates that this adhesive explant culture system is useful model for studying the cellular allergic responses to drugs ex vivo.