Protective Effects of α-Tocopherol Against Gentamicin-induced Oto-vestibulo Toxicity: An Experimental Study
- 1 February 2003
- journal article
- research article
- Published by Informa UK Limited in Acta Oto-Laryngologica
- Vol. 123 (2), 192-198
- https://doi.org/10.1080/00016480310001484
Abstract
Objective—Free radicals are involved in gentamicin ototoxicity and vestibular dysfunction and it has been demonstrated that free radical scavengers, such as α-tocopherol, are able to inactive free radicals, attenuating tissue damage. This study was designed to investigate the possible protective effects of α-tocopherol against gentamicin-induced oto-vestibulo toxicity.Material and Methods—Adult albino guinea pigs were divided into four groups and were treated for 2 weeks as follows: Group A, controls; Group B, gentamicin plus corn oil; Group C, gentamicin only; and Group D, gentamicin plus α-tocopherol. To evaluate vestibular function, the animals underwent sinusoidal oscillations in the dark about their vertical and longitudinal axes to evoke horizontal and vertical vestibulo-ocular reflexes (VORs), respectively. Electrocochleographic recordings were performed using an implanted round window electrode. The compound action potentials (CAPs) at 2, 4, 8 and 16 kHz were measured every 5 days. Morphological changes were analysed by means of scanning electron microscopy.Results—Gentamicin induced a consistent reduction in VOR responses and a progressive high-frequency hearing loss of 50–60 dB sound pressure level. α-Tocopherol co-therapy slowed the progression of hearing loss and significantly attenuated the final threshold shifts. The impairment of vestibular function was reduced, as evidenced by an increased VOR gain. The massive loss of outer hair cells in the cochlear basal turn and of cristae ampullaris stereocilia in gentamicin-treated animals was not observed in the cochlea of animals protected with α-tocopherol.Conclusion—This study supports the hypothesis that α-tocopherol interferes with gentamicin-induced free radical formation, and suggests that this drug may be useful in preventing aminoglycoside oto-vestibulo toxicity.Keywords
This publication has 12 references indexed in Scilit:
- Changes in electrovestibular brainstem responses after aminoglycoside intoxication in guinea pigs.Clinical Neurophysiology, 2001
- Aminoglycoside AntibioticsAudiology and Neurotology, 2000
- Vitamin E and heart disease:: Basic science to clinical intervention trialsFree Radical Biology & Medicine, 2000
- Apoptotic death of hair cells in mammalian vestibular sensory epitheliaHearing Research, 1999
- Stimulation of free radical formation by aminoglycoside antibioticsHearing Research, 1999
- Formation of reactive oxygen species following bioactivation of gentamicinFree Radical Biology & Medicine, 1999
- Direct detection of ototoxicant-induced reactive oxygen species generation in cochlear explantsHearing Research, 1996
- Variable efficacy of radical scavengers and iron chelators to attenuate gentamicin ototoxicity in guinea pig in vivoHearing Research, 1996
- Randomised controlled trial of vitamin E in patients with coronary disease: Cambridge Heart Antioxidant Study (CHAOS)The Lancet, 1996
- Ototoxicity in vitro: effects of neomycin, gentamicin, dihydrostreptomycin, amikacin, spectinomycin, neamine, spermine and poly-l-lysineHearing Research, 1994