Experimental model of asthma by toluene diisocyanate (TDI).

Attention has been paid to respiratory hypersensitivity in workers who are exposed to toluene diisocyanate (TDI) in their workshops. An experimental model of asthma in guinea pigs by TDI has been developed. A 10% TDI solution dissolved in ethyl acetate was painted on the nasal cavities of guinea pigs with a thin cotton applicator once daily for five consecutive days. Three weeks later, the animals were challenged with a 5% TDI solution. Exertional breathing accompanied by the prolongation of expiratory phase was observed among the test animals. The number of the animals suffering from the attacks increased by the repetitive provocations. Although some of the guinea pigs suffered from anaphylaxis by the provocation procedures, the attacks including the anaphylactic shocks hardly brought about deaths in the animals. It was found that passive transfer of the symtom was possible in our experimental system. Both eosinophilic infiltration in the lung and eosinophilia in the peripheral bood were found among the test animals. This experimental model was developed by the appliaction of a simple chemical alone to the respiratory tract of guinea pigs. A significance of the model is discussed with the review of the literatures concerned.