title: Distribution and characteristics of slow-cycling cells in rat vocal folds.
abstract: OBJECTIVE
  Stem cells are known to proliferate at a slow rate in adult organs, and thus slow-cycling cells exhibiting pluripotency are considered tissue-specific stem cells in some organs. Slow-cycling cells in the vocal fold (VF) have not been well documented. Here we sought to clarify the distributions and characteristics of slow-cycling cells in rat VFs.
  
  
  METHODS
  We applied double-labeling technique to detect the distribution of slow-cycling cells. We injected the exogenous proliferation marker 5-bromo-2'-deoxyuridine (BrdU) into Sprague-Dawley rats. After a chasing period, VFs were immunostained with antibodies to BrdU and the second endogenous proliferation marker, Ki-67. BrdU (+) Ki-67(+) cells were regarded as slow-cycling cells and counted by VF regions. To reveal slow-cycling cells' characteristic, their immunophenotypes were histologically investigated and their kinetics in injured VFs were evaluated.
  
  
  RESULTS
  Most slow-cycling cells were detected in the basal layer of the epithelium. Slow-cycling cells in the epithelium displayed a low positive ratio of E-cadherin and CK5 and a high positive ratio of vimentin and CD31 as compared with the other epithelial cells. The expression of S100A4 was low in slow-cycling cells of the lamina propria and the macula flava. FGFR1, HAS1, HAS2, and HAS3 were not detected in the slow-cycling cells. A time-dependent reduction of slow-cycling cells was observed in injured VFs.
  
  
  CONCLUSIONS
  Most slow-cycling cells resided in the epithelium, exhibiting various phenotypes in a relatively undifferentiated condition, and they are suspected to contribute to the tissue repair of the injured VFs.
  
  
  METHODS
  N/A.
authors: Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors: Yoshitaka
authors: Y
authors: Kawai
authors: Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors: Yo
authors: Y
authors: Kishimoto
authors: Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors: Ryo
authors: R
authors: Suzuki
authors: Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors: Takuya
authors: T
authors: Tsuji
authors: Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors: Nao
authors: N
authors: Hiwatashi
authors: Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors: Ichiro
authors: I
authors: Tateya
authors: Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors: Norio
authors: N
authors: Yamamoto
authors: Department of Bioartificial Organs, Institute for Frontier Medical Science, Kyoto University, Kyoto, Japan.
authors: Tatsuo
authors: T
authors: Nakamura
authors: Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.|Department of Otolaryngology-Head and Neck Surgery, Kitano Hospital, Tazuke Kofukai Medical Research Institute, Osaka, Japan.
authors: Sin-Ichi
authors: S
authors: Kanemaru
authors: Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors: Shigeru
authors: S
authors: Hirano
mesh_terms: D000818:Animals; D002453:Cell Cycle / Q000502:physiology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014827:Vocal Cords / Q000166:cytology*
keywords: Vocal fold; label retaining cell; regenerative therapy; slow-cycling cell; stem cell