A nasal allergy model developed in the guinea pig by intranasal application of 2,4-toluene diisocyanate.

An experimental model of nasal allergy has been developed in guinea pigs by intranasal application of 2,4-toluene diisocyanate (TDI). A 10% TDI solution in ethyl acetate was painted onto the nasal vestibuli of the animals once a day for 5-10 days. During the course of repeated application of TDI, the number of animals which secreted rhinorrhea containing eosinophils increased. Morphological survey of the nasal mucosa showed infiltration of eosinophils and some other changes indicative of acute inflammation. Moreover, mast cells were found not only in the subepithelial connective tissue but also in the epithelial layer. Nasal mucus obtained from the mucosa has been found to be an effective test material for studies of nasal allergy. A striking decrease of specific granules was found in some mast cells contained in the mucus. In parallel with the symptomatology, biochemical and serological studies suggested the involvement of type I allergy in the experimental system; TDI-specific histamine release from the nasal mucosa and positive passive cutaneous anaphylaxis were found 3 weeks after the application of TDI.