Prostaglandins in type II collagen-induced ear diseases.

This study examines the role of prostaglandins in type II collagen-induced inner ear disease. Hartley guinea pigs were immunized with type II collagen in complete Freund's adjuvant. Auditory brain stem response was measured initially and at 2, 3, 4, and 6 months after immunization. The presence of PGE2 and 6-keto-PGF1 alpha in the perilymph was determined by radioimmunoassay. Perilymph from immunized animals contained about five times more PGE2 and about three times more 6-keto-PGF1 alpha than the perilymph from control animals. However, the two groups showed no difference in the level of either PGE2 or 6-keto-PGF1 alpha in cerebrospinal fluid and serum. Immunized guinea pigs also showed evidence of hearing loss. The temporal bones showed the following changes: spiral ganglion degeneration; mild to moderate degeneration in the organ of Corti; and infrequent and very mild endolymphatic hydrops. Thus, prostaglandins might play an important role in the pathogenesis of type II collagen-induced inner ear disease.