title: Oxidative stress in spiral ganglion cells of pigmented and albino guinea pigs exposed to impulse noise.
abstract: CONCLUSIONS
  The results suggest that melanin inhibits formation of reactive oxygen species (ROS) and prevents apoptosis in spiral ganglion cells (SGCs) of pigmented guinea pigs following impulse noise.
  
  
  OBJECTIVE
  The stria vascularis of pigmented guinea pig cochlea contains melanocytes that produce melanin, which has a protective effect on noise-induced hair cell damage through its antioxidant property. ROS are involved in cochlear damage induced by impulse noise trauma. The purpose of the present study was to investigate the oxidative stress in SGCs of pigmented and albino guinea pigs after exposure to impulse noise.
  
  
  METHODS
  Pigmented and albino guinea pigs were exposed to impulse noise. Auditory thresholds were assessed by sound-evoked auditory brainstem response (ABR) before impulse noise exposure and 72 h after impulse noise exposure. 4-Hydroxynonenal (HNE) was used as a histochemical marker of ROS formation, and active-caspase-3 (cas-3) served as a marker for apoptosis. 4-HNE and cas-3 were determined immunohistochemically. Hair cell damage was analyzed by scanning electron microscopy.
  
  
  RESULTS
  The rates of 4-HNE-positive and cas-3-positive SGCs in pigmented guinea pigs were much less than those for albino guinea pigs. Correspondingly, there was less hair cell damage and reduced ABR threshold shifts in pigmented guinea pigs.
authors.affiliation: Department of Otolaryngology, General Hospital of PLA Guangzhou Command, China. dr_xiong@163.com
authors.forename: Min
authors.initials: M
authors.lastname: Xiong
authors.forename: Qinglian
authors.initials: Q
authors.lastname: He
authors.forename: Huangwen
authors.initials: H
authors.lastname: Lai
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000447:Aldehydes / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000502:physiology; D001933:Brain Stem / Q000503:physiopathology; D053148:Caspase 3 / Q000378:metabolism; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology; D006168:Guinea Pigs; D018072:Hair Cells, Auditory, Outer / Q000473:pathology / Q000502:physiology; D006317:Hearing Loss, Noise-Induced / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D015227:Lipid Peroxidation / Q000502:physiology; D008543:Melanins / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D018384:Oxidative Stress / Q000502:physiology*; D013136:Spiral Ganglion / Q000473:pathology / Q000503:physiopathology*
chemical_list: D000447:Aldehydes; D008543:Melanins; D053148:Caspase 3; C027576:4-hydroxy-2-nonenal