Effects of testosterone in the treatment of immune-mediated sensorineural hearing loss

Abstract

Testosterones have beneficial effects not only on the modulation of expression of autoimmunity of B/W mice, but on other unrelated models such as autoimmune thyroiditis as well. This study was performed to evaluate the effect of testosterone in the treatment of immune-mediated sensorineural hearing loss (IMSNHL). To induce IMSNHL, 29 female Wistar rats were sensitized with bovine inner ear antigen three times weekly. Fourteen of 29 rats were injected subcutaneously three times a week with 250 microg of testosterone propionate from 1 week prior to the first sensitization to 1 week following the second booster sensitization. An auditory brain-stem response (ABR) test was performed prior to each antigen challenge and at 1, 2, 3, 4, 6 and 8 weeks following sensitization. On ABR testing, the testosterone-treated animals showed better results than the control animals with IMSNHL in the degree of hearing loss (10 to 20 dB vs. 10 to 40 dB) and incidence of hearing loss over 20 dB (25.0% vs. 53.3%). None of testosterone-treated animals showed a hearing loss over 20 dB, whereas 40% of the control animals with IMSNHL revealed hearing loss over 20 dB. These results suggest that testosterone propionate may be effective in the prevention of and early recovery from IMSNHL and may be used in the future as a one treatment modality for IMSNHL.

Effects of Androgen Receptor Inhibition on Kanamycin-Induced Hearing Loss in Rats

“…A few previous studies investigated the effects of testosterone on auditory functions [12,13]. The effects of testosterone in the immunemediated sensorineural hearing loss rat models were suggested [12]. However, low level of testosterone did not change the auditory brainstem response and otoacoustic emissions in the UV-filter octyl methoxycinnamate-exposed rats [13].…”

“…To the best of our knowledge, the application of androgen antagonists and the exploration of their protective mechanisms in hearing loss have not been previously reported. A few previous studies investigated the effects of testosterone on auditory functions [12,13]. The effects of testosterone in the immunemediated sensorineural hearing loss rat models were suggested [12].…”

“…The study revealed the presence of several response elements to androgen receptors in promoter regions of megalin, implying the transcriptional regulation of megalin by androgen receptors [11]. Since a few previous studies suggested the sex differences in aminoglycoside-induced ototoxicity as well as megalin also exists in the cochlea, the suppression of megalin by androgen antagonist could have otoprotective effects in an aminoglycoside-induced ototoxicity model [10,12,13]. This study hypothesized that megalin inhibition by an androgen blocker such as flutamide (FM) might prevent aminoglycoside-induced ototoxicity.…”

Hormone Therapy: Challenges for Treating Hearing Impairments

“…Concerning androgens, immune-mediated sensorineural hearing loss (IMSNHL) has a particularly higher incidence rate in women, and testosterone exerts beneficial effects on the modulation of the expression of this autoimmunity [38]. Chang et al (2001) [39] showed that a group of mice treated with several subcutaneous injections of testosterone had better results than the IMSNHL control animals in relation to the degree of hearing loss (10 to 20 dB vs. 10 to 40 dB) and the incidence of hearing loss greater than 20 dB in the ABR results.…”