Decreased auditory function in the C3H/lpr autoimmune disease mouse

To better understand autoimmune-related inner ear disease, cochlear structure and function were evaluated in the C3H/lpr autoimmune strain mouse, a model for systemic lupus erythematosus. C3H/lpr mice were examined at ages from 2 to 12 months along with age-matched C3H/HeJ controls. Autoimmune disease onset occurred at 3-4 months of age as serum immune complexes, antinuclear antibodies, and spleen weights were significantly elevated. Auditory brainstem response (ABR) audiometry showed normal auditory thresholds in C3H/lpr mice at 4 months of age, but elevated thresholds by 6 months, particularly in the high frequencies. Examination of the cochleas revealed no apparent loss of hair cells or spiral ganglion neurons, even in those mice with 50 dB SPL threshold shifts. However, changes were observed in the stria vascularis, including edematous spaces, enlarged capillaries, and thickened vessel linings. These findings imply that cochlear dysfunction in the autoimmune disease mice is the result of stria vascularis pathology.