Protective Effect of N-acetylcysteine (NAC) Administration on Prevention of Noise-Induced Hearing Loss (NIHL) in Rabbit

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.