ABSTRACT
BACKGROUND AND OBJECTIVE: Previous reports suggest that some cases of sensorineural hearing loss (SNHL) may be the results of abnormal immune reaction. However, specific diagnostic tests and treatment have not been established. This study was performed to evaluate the effect of testosterone in the treatment of immune-mediated SNHL. MATERIALS AND METHODS: Immune-mediated SNHL was induced in female Wistar rats by sensitizing with bovine inner ear antigen 3 times weekly. Two fifty microgram of testosterone propionate was injected subcutaneously 3 times a week from one week before and after the first sensitization. Auditory brainstem response (ABR) and collection of blood were performed prior to each antigen challenge at 1, 2, 3, 4, 6, 8 weeks following sensitization. Collected sera were analyzed using the western blot immunoassay against bovine inner ear antigen preparation. RESULTS: Testosterone-treated animals showed better hearing than the controls, but they also showed incidence of hearing loss over 20 dB (25.0% vs. 53.3%). None of testosterone-treated animals showed hearing loss over 30dR, whereas 40% of control animal revealed hearing loss over 30dB. Five of 9 animals (55.5%) with hearing loss over 20 dB showed a band at 68kD MW, while only one of 14 testosterone-treated animals displayed a band at 68kD MW. CONCLUSION: These results suggest that testosterone may be effective in prevention, and early recovery from immune-mediated SNHL can be used as one of the treatment modalities for immune-mediated hearing loss in the future.