Aldosterone (Mineralocorticoid) Equivalent to Prednisolone (Glucocorticoid) in Reversing Hearing Loss in MRL/MpJ-Faslpr Autoimmune Mice

Authors

  • Dennis R. Trune PhD,

    Corresponding author
    1. Oregon Hearing Research Center, Department of Otolaryngology—Head and Neck Surgery, Oregon Health Sciences University, Portland, Oregon
    • Dennis R. Trune, PhD, Oregon Hearing Research Center, Mail Code NRC04, Oregon Health Sciences University, 3181 Southwest Sam Jackson Park Road, Portland, OR 97201-3998, U.S.A.
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  • J. Beth Kempton BS,

    1. Oregon Hearing Research Center, Department of Otolaryngology—Head and Neck Surgery, Oregon Health Sciences University, Portland, Oregon
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  • Monica Kessi BA

    1. Oregon Hearing Research Center, Department of Otolaryngology—Head and Neck Surgery, Oregon Health Sciences University, Portland, Oregon
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  • Presented at the Meeting of the Association for Research in Otolaryngology, St. Petersburg Beach, Florida, February 23, 2000.

    Research supported by Grant Nos. DC03573 and DC03955 from the National Institutes of Health—National Institute on Deafness and Other Communication Disorders; and Grant No. RCTR 597-0160 to the National Center for Rehabilitative Auditory Research (Portland, OR) from the Department of Veteran's Affairs, Division of Rehabilitation Research & Development.

Abstract

Hypothesis Although the glucocorticoid prednisone is the standard therapy for autoimmune sensorineural hearing loss, what this hormone does in the ear to restore hearing is not known. MRL/MpJ-Faslpr autoimmune mice consistently have shown only stria vascularis disease, implying that abnormal ion balances in the endolymph underlie cochlear dysfunction. Previously we have shown that hearing loss in these mice is reversed with prednisolone treatment. This, coupled with the complete lack of cochlear inflammation, suggests that the restoration of hearing with prednisolone is due to its sodium transport function and not to its anti-inflammatory or immune suppression effects. Therefore the hypothesis of this study was that the mineralocorticoid aldosterone, which only increases sodium transport, would be as effective as prednisolone in reversing autoimmune hearing loss.

Study Design MRL/MpJ-Faslpr autoimmune mice were treated with either prednisolone or aldosterone to compare steroid effects on auditory brainstem response (ABR) thresholds and stria morphology.

Methods After baseline ABR audiometry, autoimmune mice were given prednisolone (5 mg/kg per day), aldosterone (15 μg/kg per day), or water in their drinking bottles. After 2 months of treatment the ABR thresholds were remeasured, and ears collected for histological examination.

Results The untreated controls showed continued elevation of ABR thresholds and edematous stria. However, thresholds in most steroid mice were improved or unchanged and their stria morphology improved, particularly with aldosterone treatment.

Conclusions Restoration of hearing with steroid treatment is due to increased sodium transport to re-establish cochlear ionic balances. Aldosterone therapy may offer advantages over prednisone for long-term management of not only autoimmune hearing loss, but also other forms of nonimmune-related deafness for which steroids are currently prescribed.

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