title: Effect of vitamin C depletion on age-related hearing loss in SMP30/GNL knockout mice.
abstract: Using senescence marker protein 30 (SMP30)/gluconolactonase (GNL) knockout (KO) mice, which cannot synthesize vitamin C (VC), we examined whether modulating VC level affects age-related hearing loss (AHL). KO and wild-type (WT) C57BL/6 mice were given water containing 1.5 g/L VC [VC(+)] or 37.5mg/L VC [VC(-)]. At 10 months of age, KO VC(-) mice showed significant reduction in VC level in the inner ear, plasma, and liver, increase in auditory brainstem response (ABR) thresholds, and decrease in the number of spiral ganglion cells compared to WT VC(-), WT VC(+), and KO VC(+) mice. There were no differences in VC level in the inner ear, ABR thresholds, or the number of spiral ganglion cells among WT VC(-), WT VC(+), and KO VC(+) mice. These findings suggest that VC depletion can accelerate AHL but that supplementing VC may not increase VC level in the inner ear or slow AHL in mice.
authors.affiliation: Department of Otolaryngology and Head and Neck Surgery, University of Tokyo, Tokyo 113-8655, Japan.
authors.forename: Akinori
authors.initials: A
authors.lastname: Kashio
authors.forename: Akiko
authors.initials: A
authors.lastname: Amano
authors.forename: Yoshitake
authors.initials: Y
authors.lastname: Kondo
authors.forename: Takashi
authors.initials: T
authors.lastname: Sakamoto
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Iwamura
authors.forename: Mitsuya
authors.initials: M
authors.lastname: Suzuki
authors.forename: Akihito
authors.initials: A
authors.lastname: Ishigami
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Yamasoba
mesh_terms: D000375:Aging / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000096:biosynthesis / Q000502:physiology*; D001206:Ascorbic Acid Deficiency / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology*; D001309:Auditory Threshold; D002135:Calcium-Binding Proteins / Q000235:genetics; D002265:Carboxylic Ester Hydrolases / Q000235:genetics; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics; D051379:Mice; D018345:Mice, Knockout; D011304:Presbycusis / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D013136:Spiral Ganglion / Q000378:metabolism* / Q000473:pathology
chemical_list: D002135:Calcium-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; C513324:Rgn protein, mouse; D002265:Carboxylic Ester Hydrolases; C020579:gluconolactonase; D001205:Ascorbic Acid