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Ascorbic Acid Reduces Noise‐Induced Nitric Oxide Production in the Guinea Pig Ear
Author(s) -
Heinrich UlfRüdiger,
Fischer Ilka,
Brieger Jürgen,
Rümelin Andreas,
Schmidtmann Irene,
Li Huige,
Mann Wolf J.,
Helling Kai
Publication year - 2008
Publication title -
the laryngoscope
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.181
H-Index - 148
eISSN - 1531-4995
pISSN - 0023-852X
DOI - 10.1097/mlg.0b013e31816381ae
Subject(s) - ascorbic acid , organ of corti , guinea pig , nitric oxide , chemistry , inner ear , medicine , anatomy , food science
Objectives: Noise‐induced hearing loss can be caused, among other causes, by increased nitric oxide (NO) production in the inner ear leading to nitroactive stress and cell destruction. Some studies in the literature suggest that the degree of hearing loss (HL) could be reduced in an animal model through ascorbic acid supplementation. To identify the effect of ascorbic acid on tissue‐dependent NO content in the inner ear of the guinea pig, we determined the local NO production in the organ of Corti and the lateral wall separately 6 hours after noise exposure. Study Design: Prospective animal study in guinea pigs. Methods: Over a period of 7 days, male guinea pigs were supplied with minimum (25 mg/kg body weight/day) and maximum (525 mg/kg body weight/day) ascorbic acid doses, and afterwards exposed to noise (90 dB sound pressure level for 1 hour). The acoustic‐evoked potentials were recorded before and after noise exposure. The organ of Corti and the lateral wall were incubated differently for 6 hours in culture medium, and the degree of NO production was determined by chemiluminescence. Results: Ascorbic acid treatment reduced the hearing threshold shift after noise exposure depending on concentration. When the maximum ascorbic acid dose was substituted, NO production was significantly reduced in the lateral wall after noise exposure and slightly reduced in the organ of Corti. Conclusions: Oral supplementation of the natural radical scavenger ascorbic acid reduces the NO‐production rate in the inner ear in noisy conditions. This finding supports the concept of inner ear protection by ascorbic acid supplementation.