Effects of an amphoteric antiallergic agent, HSR-609, on antigen-induced late phase nasal eosinophilia in brown Norway rats.

The effect of a newly synthesized compound, HSR-609, on rat experimental rhinitis was investigated. In the first part of the study, a new experimental nasal allergic late phase eosinophilia model in Brown Norway (BN) rats was investigated. The increase in the number of antigen inhalations resulted in the proportional increase in the number of inflammatory cells such as macrophages, eosinophils and neutrophils in the nasal cavity lavage fluid (NCLF) at 5 h after each inhalation. The number of inflammatory cells reached a maximum 8 h after the antigen perfusion. Submaximum response was observed at 5 h after the antigen provocation. In this system, the serum IgG and IgE antibody titers measured by homologous passive cutaneous anaphylaxis were 160 and 640, respectively. In the second part of the study, the effects of prednisolone, cetirizine and a newly synthesized amphoteric antiallergic agent, HSR-609, on this allergic late nasal eosinophilia and neutrophilia in BN rats were investigated. Prednisolone and HSR-609 significantly inhibited the increase in the number of eosinophils in the NCLF but not cetirizine. Furthermore, prednisolone showed the inhibition of the increase in the number of macrophages and neutrophils in NCLF. These results suggest that this late phase eosinophilia model in the nose of BN rats may be useful for investigating the therapeutic drugs for nasal allergy and a newly synthesized amphoteric antiallergic agent, HSR-609, may be useful for the treatment of allergic rhinitis with eosinophilia.