In 1981, the authors described a
type II collagen-induced autoimmune
ear disease (CIAED) model. The purpose of this study was to gather further evidence that this is a sound animal model to use in evaluating
inner ear diseases. The temporal bone lesions of CIAED in Lewis and Wistar rats were characterized by the presence of
sensorineural hearing loss with mild
atrophy of the organ of Corti and spiral ganglion degeneration, vestibular dysfunction with vacuolar degeneration of the crista ampullaris,
otospongiosis-like lesions in the tympanic annules, cochlear
vasculitis, and eustachian tube disease. Both cellular and humoral immune responses to
type II collagen were demonstrated. The induction of ear lesions depends on many factors. In general, animals immunized with
antigens in complete
Freund's adjuvant showed relatively more severe lesions than animals immunized with
antigens in
incomplete Freund's adjuvant, but the duration of the immunization seems to be a more important factor in reproducing severe lesions. The strain and the source of the animals are also important factors in autoimmune
inner ear diseases, as is the condition of the host animals. Subclinical or clinical
mycoplasma infection in the rat markedly reduced the incidence and severity of lesions in
type II collagen-induced
arthritis. Many researchers did not consider sialoductal adenovirus, widely present among laboratory rats, a lesion-producing factor in rats. Although many factors influence the induction and severity of CIAED, these animal models provide an excellent new avenue of inner ear research.