title: [Effects of noise on antioxidant enzymes of cochlea in guinea pigs].
abstract: OBJECTIVE
  To investigate the effect of noise on the antioxidant enzymes of cochleae.
  
  
  METHODS
  16 male pigmented guinea pigs (250 - 300 g) were randomly divided into 2 groups, control group and noise group. Each group had 8 animals. The animals in noise group were performed auditory evoked brainstem responses (ABR) recording before and after exposure to a continuous noise (4 kHz, octave band, 100 dB, SPL) 8 h/d for 3 consecutive days. Immediately at the end of the third day's noise exposure after ABR recording, guinea pigs were decapitated. Both the right and the left cochlea with the bony capsule removed were homogenized, and the supernatants were prepared for assays. Reactive oxygen species (ROS), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) were measured.
  
  
  RESULTS
  ROS level of the noise group [(281.2 +/- 3.5) U/mg pro] was significantly higher than that of the control group [(273.0 +/- 3.2) U/mg pro, P < 0.05] and SOD, CAT and GSH-Px activities of the noise group [(206.5 +/- 5.1) NU/mg pro, (47.0 +/- 9.0) U/g pro, (14.1 +/- 2.5) U/mg pro respectively] were significantly lower than that of the control group [(221.8 +/- 4.8) NU/mg pro, (60.8 +/- 9.9) U/g pro, (21.1 +/- 3.1) U/mg pro respectively, P < 0.05].
  
  
  CONCLUSIONS
  Noise may damage the defensive system of antioxidant enzymes in cochlea.
authors.affiliation: Department of Occupational Hygiene, School of Public Health, Health Science Center, Peking University, Beijing 100083, China.
authors.forename: Fen-xia
authors.initials: FX
authors.lastname: Hou
authors.forename: Sheng
authors.initials: S
authors.lastname: Wang
authors.forename: Yin-yan
authors.initials: YY
authors.lastname: Hu
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000032:analysis* / Q000494:pharmacology; D002374:Catalase / Q000378:metabolism; D003051:Cochlea / Q000201:enzymology*; D016057:Evoked Potentials, Auditory, Brain Stem; D005979:Glutathione Peroxidase / Q000378:metabolism; D006168:Guinea Pigs; D008297:Male; D009622:Noise / Q000009:adverse effects*; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D000975:Antioxidants; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase