protective effect of n-acetylcysteine against continuous noise-induced hearing loss

Background: this study aimed to determine the preventive effect of n-acetylcysteine (nac) against continuous noise-induced hearing loss.materials & methods: a total of 24 adult male wistar rats were randomly assigned into 4 groups of 6 animals: control, noise, noise and nac, noise and saline. animals were subjected to 102 db (102±0.5) of continuous, 8 khz-centered high pass white noise. for two days before to noise, one hour prior to noise for ten days in a row, and two days after noise, nac (325 mg/kg) was intraperitoneally administered. temporary and permanent hearing loss were assessed by pre and post noise (1, 7 and 21 days) recordings of distortion product otoacoustic emissions (dpoaes). results: amplitudes was temporally reduced significantly first day post noise exposure in all groups, and all frequencies (p<0.05). the initial and subsequent recovery was more pronounced in noise-exposed animal treated with nac compared to those received noise and saline, especially in higher frequencies (p<0.05). noise and nac group experienced less permanent hearing loss than noise and saline group (p<0.05). conclusions: nac could partially improve permanent hearing loss after noise exposure however, temporary hearing loss was not affected by nac.