%0 Journal Article %T The protective effect of moderate noisy backgrounds for certain period on hearing after exposure to a traumatic noise in guinea pig %A Xiao-hua WANG %A Jian-cheng ZHANG %A Yan-jun WANG %A Hong-yuan ZHOU %J Medical Journal of Chinese People's Liberation Army %D 2013 %I Editorial Board of Medical Journal of Chinese People's Liberation Army %X Objective ¡¡To investigate the protective effect of moderate noisy backgrounds on guinea pig's hearing after an exposure to a traumatic noise. Methods ¡¡Thirty guinea pigs were randomly divided into five groups (6 each). Animals in group A, B, C and D were subjected to noise of 84 decibels sound pressure level (dB SPL) for 4, 8, 24 and 0 hour respectively after a traumatic exposure of 110 dB SPL, and those in group E were kept in quiet environment. Distortion product oto-acoustic emission (DPOAE) amplitudes were determined on 1 day prior, and 1 and 7 days after noise exposure. Blood plasma was obtained to determine the contents of malondialdehyde (MDA) and the activities of hemocuprein (SOD) and nitricoxide synthase (NOS) at the end of the experiment. Results ¡¡Noise-induced hearing loss was caused in group D after a traumatic exposure. At the 1st and 7th day after exposure, DPOAE amplitudes were higher in group A and B than in group D, especially at high frequencies, while no significant difference was observed between group C and D. At the 7th day after exposure, the activity of SOD lowered, while the content of MDA increased in group A and B as compared with group E (P<0.05). The content of MDA in group A increased as compared with group D (P<0.05). Conclusion ¡¡After the traumatic noise-exposure, the recovery of noise-induced hearing loss, especially the high-frequency hearing loss could be motivated when exposed to noise at 84 dB SPL for 4 or 8 hours. %K noise %K otoacoustic emissions %K spontaneous %K auditory perceptual disorders %K reactive oxygen species %U http://www.plamj.org/index.php/plamj/article/view/674