Gentamicin Applied to the Oval Window Suppresses Vestibular Function in Guinea Pigs

Area of Science:

• Oto-neurology
• Oto-toxicology
• Experimental Otology

Background:

• Intratympanic gentamicin is a common treatment for Ménière's disease.
• Cochleotoxicity and hearing loss are risks associated with gentamicin therapy.
• Gentamicin absorption via the oval window has been previously demonstrated.

Purpose of the Study:

• To evaluate the efficacy of direct vestibular treatment using gentamicin.
• To assess the impact of applying gentamicin to the stapes footplate on vestibular and cochlear function.
• To investigate the potential for targeted cochlear treatment with reduced ototoxicity.

Main Methods:

• Guinea pigs were treated by applying a small volume of gentamicin onto the stapes footplate.
• Vestibular function was assessed using vestibular evoked potentials (VEPs) in response to linear acceleration.
• Cochlear function was evaluated by measuring hearing thresholds; histopathology of vestibular and cochlear tissues was performed.

Main Results:

• Vestibular responses were significantly suppressed by 72.7% two weeks post-treatment.
• No significant hearing loss was observed in the treated animals.
• Histopathology confirmed targeted effects on vestibular structures.

Conclusions:

• Directly treating the vestibule via the stapes footplate with gentamicin is effective.
• This method significantly suppresses vestibular function while preserving hearing.
• This approach offers a promising strategy for Ménière's disease treatment with reduced cochleotoxicity.