Protective Effects of Corticosteroids and Neurosteroids on Cochlear injury

Keiji      Tabuchi; Mariko      Nakamagoe; Bungo      Nishimura; Kentaro      Hayashi; Masahiro      Nakayama; Akira      Hara

Abstract

Dysfunction of the cochlea causes sensorineural hearing loss. Glucocorticoids have been clinically applied for sensorineural hearing loss of sudden onset, including idiopathic sudden sensorineural hearing loss, acoustic injury, Menieres disease, and immune-mediated hearing loss. However, clinical studies on sudden sensorineural hearing loss have revealed conflicting results regarding the efficacy of glucocorticoids. The findings obtained from animal experiments have demonstrated that glucocorticoids exhibited protective effects on some types of cochlear injury, but there were limitations regarding glucocorticoid therapy. Recently, the actions of neurosteroids in the cochlea have drawn much attention from auditory researchers. Clinical and experimental studies of the auditory system have indicated that estrogens affect auditory perception. Furthermore, estrogens and dehydroepiandrosterone (DHEA) exhibit protective effects on cochlear injury. This article was aimed to give an overview of steroid treatment for protection of the inner ear against various cochlear injuries. Findings obtained from animal studies are focused on.

Keywords: Cochlea, sensorineural hearing loss, glucocorticoid, neurosteroid, estroge, steroid, Meniere's disease, acoustic injury, inner ear, cochlear injury, DHEA, auditory system, labyrinthitis, ototoxic agents