Heat shock protein 70 delays gentamicin-induced vestibular hair cell death

In this study, geranylgeranylacetone (GGA) was shown to induce heat shock protein (HSP)70 in the vestibular end organs of the guinea pig and to alleviate gentamicin (GM) ototoxicity. This was accomplished without thermal preconditioning. In isolated guinea pig vestibular end organs we demonstrated possible prophylactic (preventive) effects of GGA on GM ototoxicity by actively inducing HSP70. When HSP70 was pre-incubated with GGA, its content in sensory cell cytoplasm and transitional dark cells was increased. Pre-incubation of vestibular end organs with GGA gave sensory cells partial protection from GM toxicity. These findings show that administration of GGA can protect vestibular sensory cells from GM ototoxicity and suggest that induction of HSP70 by GGA may be a useful adjunct for the treatment of vestibular disorders.