Oxidative stress and cochlear damage

The cochlea is the sensory organ responsible for converting sounds to electrical signals, an essential step in the generation of the hearing sensation. In the mammalian cochlea, sensory cells are unable to regenerate when fatally damaged, and their loss leads to permanent hearing loss. Over the years, intensive studies have focused on the biological and molecular mechanisms responsible for cochlear pathogenesis in various cochlear disorders. A growing body of evidence has implicated oxidative stress in sensory cell damage in the cochlea. Oxidative stress has been found to be a common mechanism for various cochlear pathogeneses, including noise- and ototoxic drug-induced, and age-related cochlear degeneration. These findings have led to intensive studies for antioxidant therapies, and several promising drugs have been identified. Although clearly demonstrated in experimental animals, the effectiveness of antioxidant treatments in patients remains to be confirmed. The current review provides an overview of the roles of oxidative stress in the development of common inner ear disorders and antioxidant therapies for treatment of these disorders.