[Protective effect of N-acetylcysteine [NAC] administration on prevention of noise-induced hearing loss [NIHL] in rabbit]

ABSTRACT

Oxidative stress due to free radicals formation plays an important role in noise-induced hearing loss [NIHL]. Many hypotheses have been proposed regarding the biochemical prevention of this complication. This study was performed with the purpose of determining the preventive effect of N-acetylcysteine [NAC] administration, as an antioxidant agent, on NIHL in Rabbit. In an experimental study, 24 adult white male rabbits were divided into four groups, including 1] control, 2] noise exposure [100dB octave band noise centered at 4000Hz for 40h], 3] noise exposure plus NAC administration [325mg/kg, daily ip injection], and 4] no exposure and NAC administration. Audiometric test of rabbits was assessed by auditory brainstem response [ABR] technique in three stages. The Kruskal-Wallis and Mann-Whitney tests were used to compare the groups, and a p<0.05 was considered significant. The mean ABR threshold shift for the noise exposure plus NAC administration group, 1 hour after exposure at 1, 2, 4 and 8kHz frequencies were, respectively, 16.66 +/- 1.63, 21.66 +/- 1.75, 33.5 +/- 2.34, and 39.33 +/- 2.25dB. These values were significantly less than the same values in the noise exposure group. The results of this study showed that NAC can provide a proper protective effect against hearing loss resulting from noise exposure