Otitis media induced by inoculation of a chemotactic factor.

Phagocytic cells in middle ear effusion obtained from patients with acute or chronic otitis media, have antibacterial activity which is an element of the host defense system. In addition, they modify inflammatory responses as they release degranulated substances, phospholipid-derived substances, and active oxygens. To demonstrate both the direct and indirect biological activities of chemotactic factor through migrating inflammatory phagocytic cells in acute otitis media, a synthetic chemotactic peptide, formyl-methionyl-leucyl-phenylalanine (fmlp), was inoculated into the middle ear of guinea pigs. Fmlp induced severe vascular damage, mucosal edema, and infiltration of phagocytic cells 1 and 3 days after inoculation and interstitial fibrosis and calcification 2 weeks after inoculation. Chemotactic factor in the middle ear cavity caused middle ear tissue damage and may play a role in the development of acute and chronic otitis media.