A reexamination of experimental type II collagen autoimmunity: middle and inner ear morphology and function.

Type II collagen autoimmunity has been reported to result in a number of middle and inner ear morphological and functional abnormalities. We investigated the immunological, electrophysiological, and anatomical effects of this autoimmune state in well-established Wistar-Furth rat models of type II collagen autoimmune arthritis. Seventeen animals immunized with bovine type II collagen were divided into short term (1-3 months postimmunization) and long term (9-11 months) groups. Thirty-three experimental ears were tested electrophysiologically and were compared to nine ears of unimmunized Wistar-Furth rats. No hearing loss was found in the immunized animals, except for four animals that showed middle ear abscess formation consistent with spontaneous, purulent otitis media. All immunized animals showed very significant serum and perilymph antibody titers to type II collagen. No morphological abnormalities of the external, middle, or inner ears could be identified in the noninfected experimental animals. These findings do not support previously reported observations that type II collagen autoimmunity results in ear disease.