Steroid treatment in young MRL.MpJ-Fas(lpr) autoimmune mice prevents cochlear dysfunction

Corticosteroid therapy reverses clinical autoimmune sensorineural hearing l oss, although little is known of how steroids restore normal auditory funct ion. If suppression of systemic autoimmune processes underlies hearing rest oration, then preventing autoimmune symptoms from developing should prevent cochlear dysfunction. MRL.MpJ-Fas(lpr) autoimmune mice were used to test t his potential mechanism by initiating oral prednisolone treatment at 6 week s of age, prior to autoimmune disease and hearing loss onset. The steroid t reatment group was given prednisolone in their drinking water, while untrea ted controls were given tap water. Treatment continued for 7 months with pe riodic evaluations of cochlear function with auditory brainstem response (A BR) audiometry. Autoimmune mice given the steroid lived longer and did not develop levels of serum immune complexes seen in their untreated controls. Also, their ABR thresholds remained near normal throughout the 7 months of treatment: while untreated controls showed progressive threshold elevations typical for autoimmune disease. This correlation of suppressed systemic au toimmune activity and maintenance of normal cochlear function identifies on e potential mechanism for autoimmune hearing loss and hearing restoration w ith steroid therapy. The autoimmune mouse should serve as a valuable model for future studies of the cochlear mechanisms responsive to steroid treatme nt in autoimmune hearing loss. (C) 1999 Elsevier Science B.V. All rights re served.