title: Age-related hearing loss and expression of antioxidant enzymes in BDF1 mice.
abstract: CONCLUSIONS
  Our data suggest that the changes in expression of antioxidant enzymes may cause age-related hearing loss (AHL).
  
  
  OBJECTIVE
  AHL is an aging process of the inner ear, and oxidant stressors are considered to be one of the leading causes. We investigated the hearing level and expression profile of antioxidant enzymes in aged mice.
  
  
  METHODS
  Mice aged 3, 6, and 11 months were used. Hearing levels of the mice were examined using the auditory brainstem response (ABR). After measuring the ABR threshold, cochleae were dissected. RNA was isolated from the cochleae, and cDNA was synthesized using the retro-transcription enzyme. Expression of the antioxidant enzymes was measured by quantitative real-time PCR.
  
  
  RESULTS
  The ABR thresholds of the BDF1 mice were elevated by 6 months of age. The expression of superoxide dismutase 1 (SOD1) and heme oxygenase 1 (HO1) at 11 months of age significantly decreased compared with that of those at 6 months of age. In contrast, a decrease in the expression level was not observed regarding NAD(P)H-quinone oxidoreductase 1 (NQO1).
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Japan. ktabuchi@md.tsukuba.ac.jp
authors.forename: Keiji
authors.initials: K
authors.lastname: Tabuchi
authors.forename: Tomofumi
authors.initials: T
authors.lastname: Hoshino
authors.forename: Yuki
authors.initials: Y
authors.lastname: Hirose
authors.forename: Kentaro
authors.initials: K
authors.lastname: Hayashi
authors.forename: Bungo
authors.initials: B
authors.lastname: Nishimura
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nakayama
authors.forename: Akira
authors.initials: A
authors.lastname: Hara
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D016057:Evoked Potentials, Auditory, Brain Stem; D006198:Hair Cells, Auditory / Q000473:pathology; D034381:Hearing Loss / Q000201:enzymology* / Q000473:pathology; D051547:Heme Oxygenase-1 / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D013136:Spiral Ganglion / Q000473:pathology; D013482:Superoxide Dismutase / Q000378:metabolism*; D000072105:Superoxide Dismutase-1
chemical_list: D012333:RNA, Messenger; C000606290:SOD1 protein, human; D051547:Heme Oxygenase-1; C000606291:Sod1 protein, mouse; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1; D016660:NAD(P)H Dehydrogenase (Quinone); C491732:Nqo1 protein, mouse