Nitro-L-arginine methyl ester: A potential protector against gentamicin ototoxicity

Conclusion. The nitric oxide (NO) inhibitor nitro-L-arginine methyl ester (L-NAME) may act as an otoprotectant against high-frequency hearing loss caused by gentamicin, but further studies are needed to confirm this. Objective. Aminoglycoside antibiotics are still widely used by virtue of their efficacy and low cost. Their ototoxicity is a serious health problem and, as their ototoxic mechanism involves the production of NO, we need to assess the use of NO inhibitors for the prevention of aminoglycoside-induced sensorineural hearing loss. Material and methods. In this experimental study we used 30 Sprague-Dawley rats, 27 of which had gentamicin instilled into the middle ear. The otoprotectant L-NAME was administered topically to 12/27 animals. Its effect was determined in terms of attenuation of hearing loss, measured by shifts in the auditory brainstem response threshold. Results. L-NAME reduced gentamicin-induced hearing loss in the high-frequency range, but gave no protection in the middle or low frequencies.