アレルギー性炎症と鼻粘膜過敏性-鼻アレルギーモルモットにおける検討

抄録

An animal experiment was performed to elucidate the effects of systemic antigen sensitization followed by repeated nasal antigen challenges on nasal reactivity to histamine and its histopathological and immunopharmacological backgrounds. One hundred and eleven Hartley strain guinea pigs were sensitized with ovalbumin intraperitoneally 7 times every 2 weeks, followed by nasal antigen challenges once daily for 7 days. Nasal reactivity to histamine and to antigen was evaluated by recording the respiratory noises.1 week after repeated antigen challenges, single antigen challenge was performed. After recording of the respiratory noises, the animals were decapitated consecutively. The nasal mucosa of the left nasal cavity was removed immediately and the contents of LTC4 in the nasal mucosa were measured by radioimmunoassay combined with HPLC. The right nasal cavity including the nasal septum was cut vertically at a fixed level and the numbers of eosinophils and neutrophils in the nasal mucosa of an entire vertical section of the nasal cavity were calculated.
During the 12 weeks of systemic sensitization, no change was observed in nasal reactivity to histamine. However it increased dramatically during the 1 week of repeated antigen challenge. The numbers of eosinophils and neutrophils increased significantly after a single antigen challenge, reaching a peak at the 12th and 3rd hour, respectively. Both LTC4 and LTD4 increased singnificantly in 15 minutes and lasted for 3 hours after the antigen challenge. However second peak corresponding to the peak of eosinophil infiltration in the nasal mucosa could not be observed. Increase of respiratory noise could not be observed at the time of maximum eosinophil infiltration. The present study revealed a close association between the development of nasal hyperreactivity and that of allergic inflammation in the nasal mucosa. However lack of findings to show degranulation of markedly infiltrated eosinophils in late phase indicated the possible participation of other factors besides degranulation of eosinophils in the late phase.