Antiinflammatory effects of a corticosteroid and protease inhibitor agents on antigen-induced otitis media in chinchillas

Using an antigen-induced otitis media (OM) model in chinchillas sensitized with humanserum albumin (HSA), we studied the antiinflammatory effect of a corticosteroid (triamcinolone) and a protease (kallikrein) inhibitor (aprotinin) by conducting both biochemical and cytologic analyses of middle ear fluid (MEF). The levels of HSA, α₁-antitrypsin, α₂-macroglobulin, and total protein concentration were measured in the MEF to evaluate the degree of OM. Both vascular leakage and leukocyte infiltration were significantly reduced by corticosteroid and inhibitor treatments. HSA levels in the MEF were markedly reduced after HSA challenge, and both treatments reduced the drop in HSA levels. In conclusion, the kallikrein-kinin system is related to the early stage of antigen-induced OM. Both corticosteroid and inhibitor treatments effectively reduce the degree of antigen-induced OM in chinchillas, suggesting that both may be useful local therapeutic agents in the treatment of human OM.