Protective properties of antioxidant drugs in noise-induced hearing loss in the guinea pig

Abstract

Oxidative stress plays a significant role in noise-induced hearing loss (NIHL), as it largely participates in the mechanisms that underlie cell death after noise exposure and lead to sensorineural hearing loss. Many antioxidant drugs have been tested to prevent NIHL. We present three molecules with antioxidant properties (vitamin E, idebenone, N-L-acetylcysteine) that have been studied in our laboratory, and compare their protective effects. We induced acoustic trauma in treated guinea pigs, evaluated their hearing function via electrophysiological measurements at 1, 7 and 21 days, and performed morphological studies with scanning electron microscopy and TUNEL assay. All molecules had a certain effect in protecting hair cells from oxidative stress; vitamin E offered almost complete protection (80–95%), N-L-acetylcysteine and idebenone also significantly reduced the threshold shift and hair cell loss. Our results support the effectiveness of antioxidant drugs in protecting against NIHL and provide a rationale for exploring therapeutic strategies in humans.

• noise-induced hearing loss
• acoustic trauma
• antioxidant
• oxidative stress
• cochlea