title: Localization of sirtuins (SIRT1-7) in the aged mouse inner ear.
abstract: CONCLUSIONS
  The expression of sirtuin in vestibular end organs and cochlea responds differently to age-related changes. Down-regulation of SIRT1, 3, and 5 in the cochlea may weaken the protective activity regarding degeneration of the organ of Corti as well as of spiral ganglion cells, resulting in the development of age-related hearing loss. An increase in SIRT 1, 4, or 5 in vestibular tissue could indicate an increased need of detoxification of reactive oxygen species and an increased anti-ageing potential.
  
  
  OBJECTIVE
  To analyse the expression of sirtuins (SIRT1-7) in the normal young and old mouse inner ears.
  
  
  METHODS
  Young (8 weeks) and old (22 months) CBA/J mice were used in this study. Localization of SIRT1-7 in the inner ear, i.e. cochlea, vestibular end organs, and vestibular ganglion, was investigated using real-time PCR and immunohistochemistry.
  
  
  RESULTS
  In the vestibular end organs, the expression of SIRT1, 2, 4, 5 (both mRNA and protein), SIRT6, and 7 (only mRNA) was found to be increased, while a slightly decreased immunoreactivity was observed in SIRT3. In the cochlea, the expression of SIRT1, 3, and 5 (both mRNA and protein) was decreased in the old mice, whereas no noticeable difference was observed regarding SIRT2, 4, 6, or 7.
authors.affiliation: a Department of Otolaryngology , Hiroshima University Hospital , Hiroshima , Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Takumida
authors.affiliation: b Faculty of Medicine, The University of Tokyo , Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Takumida
authors.affiliation: a Department of Otolaryngology , Hiroshima University Hospital , Hiroshima , Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Katagiri
authors.affiliation: c Department of Surgical Sciences , Section of Otorhinolaryngology - Head and Neck Surgery, Uppsala University , Uppsala , Sweden.
authors.forename: Matti
authors.initials: M
authors.lastname: Anniko
mesh_terms: D000375:Aging / Q000235:genetics*; D000818:Animals; D007758:Ear, Inner / Q000000981:diagnostic imaging / Q000254:growth & development / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D007150:Immunohistochemistry; D051379:Mice; D008808:Mice, Inbred CBA; D012333:RNA, Messenger / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D056564:Sirtuin 1 / Q000378:metabolism*; D056566:Sirtuin 3 / Q000096:biosynthesis / Q000235:genetics*; D037761:Sirtuins / Q000096:biosynthesis / Q000235:genetics*; D014057:Tomography, X-Ray Computed
chemical_list: D012333:RNA, Messenger; C542554:SIRT5 protein, mouse; C525046:Sirt3 protein, mouse; C470545:Sirt1 protein, mouse; D056564:Sirtuin 1; D056566:Sirtuin 3; D037761:Sirtuins
keywords: Sirtuin; ageing; inner ear; mouse; presbycusis