Effect of PAF-antagonists on aeroallergen-induced bronchial eosinophilia in guinea pigs: a therapeutic approach.

Aeroallergen-induced eosinophilia in actively sensitized guinea pigs was used as a marker of bronchial inflammation in this study. Drugs were administered p.o. therapeutically, i.e., four hours after aeroallergen challenge. Allergic bronchial eosinophilia in guinea pigs was sensitive to dexamethasone. Thus, the therapeutic approach appears to be a reliable, predictable, and sensitive for the evaluation and selection of potential bronchial anti-inflammatory compounds. PAF-antagonists (WEB-2086, WEB-2170, and E-6123) and a 5-lipoxygenase inhibitor (E-6080) did not influence allergen-induced eosinophil infiltration in the bronchoalveolar lavage fluid. These observations seem to suggest that therapeutic administration of PAF antagonists and leukotriene synthesis inhibitors exert little or no inhibitory effect on the progression of late-phase allergic bronchial inflammation in this model.