Noise-Induced Neural Degeneration and Therapeutic Effect of Antioxidant Drugs.
10.7874/jao.2015.19.3.111
- Author:
Seong Hee CHOI
1
;
Chul Hee CHOI
Author Information
1. Department of Audiology & Speech Language Pathology, Research Institute of Biomimetic Sensory Control, and Catholic Hearing Voice Speech Center, Catholic University of Daegu, Gyeongsan, Korea. cchoi@cu.ac.kr
- Publication Type:Review
- Keywords:
Noise-induced hearing loss;
Antioxidant drugs;
Neural degeneration;
Oxidative stress
- MeSH:
Acetylcarnitine;
Antioxidants;
Biomarkers;
Cell Death;
Cochlea;
Cochlear Nerve;
Free Radicals;
Hair;
Hearing Loss, Noise-Induced;
Malondialdehyde;
Nitric Oxide Synthase Type II;
Noise;
Organ of Corti;
Oxidative Stress;
Presynaptic Terminals;
Sodium;
Spiral Ganglion
- From:Journal of Audiology & Otology
2015;19(3):111-119
- CountryRepublic of Korea
- Language:English
-
Abstract:
The primary site of lesion induced by noise exposure is the hair cells in the organ of Corti and the primary neural degeneration occurs in synaptic terminals of cochlear nerve fibers and spiral ganglion cells. The cellular basis of noise-induced hearing loss is oxidative stress, which refers to a severe disruption in the balance between the production of free radicals and antioxidant defense system in the cochlea by excessive production of free radicals induced by noise exposure. Oxidative stress has been identified by a variety of biomarkers to label free radical activity which include four-hydroxy-2-nonenal, nitrotyrosine, and malondialdehyde, and inducible nitric oxide synthase, cytochrome-C, and cascade-3, 8, 9. Furthermore, oxidative stress is contributing to the necrotic and apoptotic cell deaths in the cochlea. To counteract the known mechanisms of pathogenesis and oxidative stress induced by noise exposure, a variety of antioxidant drugs including oxygen-based antioxidants such as N-acetyl-L-cystein and acetyl-L-carnitine and nitrone-based antioxidants such as phenyl-N-tert-butylnitrone (PBN), disufenton sodium, 4-hydroxy PBN, and 2, 4-disulfonyl PBN have been used in our laboratory. These antioxidant drugs were effective in preventing or treating noise-induced hearing loss. In combination with other antioxidants, antioxidant drugs showed a strong synergistic effect. Furthermore, successful use of antioxidant drugs depends on the optimal timing of treatment and the duration of treatment, which are highly related to the time window of free radical formation induced by noise exposure.
