Effect of vitamin C depletion on age-related hearing loss in SMP30/GNL knockout mice.
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.
Kashio
Akinori
A
Department of Otolaryngology and Head and Neck Surgery, University of Tokyo, Tokyo 113-8655, Japan.
Amano
Akiko
A
Kondo
Yoshitake
Y
Sakamoto
Takashi
T
Iwamura
Hitoshi
H
Suzuki
Mitsuya
M
Ishigami
Akihito
A
Yamasoba
Tatsuya
T
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
D002135:Calcium-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; C513324:Rgn protein, mouse; D002265:Carboxylic Ester Hydrolases; C020579:gluconolactonase; D001205:Ascorbic Acid