title: Proliferation, migration and apoptosis of periodontal ligament cells after tooth replantation.
abstract: OBJECTIVE
  The aim of this study was to investigate the proliferation, migration and death of periodontal ligament (PDL) cells after tooth replantation.
  
  
  METHODS
  Maxillary first molars were extracted from 4-week-old male (n = 28) Sprague-Dawley rats and immediately replanted, after which, proliferation, migration and death of PDL cells were investigated.
  
  
  RESULTS
  At 3 days after tooth replantation, many proliferative cell nuclear antigen (PCNA)-positive PDL cells were observed on the alveolar bone side, but fewer on the root side. However, while a gradual decrease was observed in number of PCNA-positive PDL cells on the alveolar bone side until 7 days, an increase was seen on the root side. At 3 weeks, cells labeled with PKH26 (fluorescent dye into plasma membrane) were located in the middle of the PDL space. However, these PKH26-labeled cells did not spread to the surface of the cementum or the alveolar bone. TUNEL-positive cells were observed on both the bone and root sides at 3 days. Number of apoptotic cells increased until 7 days on the bone sides, but decreased on root sides.
  
  
  CONCLUSIONS
  These results suggest that both cell proliferation and apoptosis occur in different patterns and at different times to maintain regular spacing of the PDL after tooth replantation.
authors.affiliation: Department of Pathology, Tokyo Dental College, Mihama-ku, Chiba, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Sato
authors.forename: T
authors.initials: T
authors.lastname: Muramatsu
authors.forename: Y
authors.initials: Y
authors.lastname: Tsuchiya
authors.forename: T
authors.initials: T
authors.lastname: Masaoka
authors.forename: Y
authors.initials: Y
authors.lastname: Enokiya
authors.forename: S
authors.initials: S
authors.lastname: Hashimoto
authors.forename: M
authors.initials: M
authors.lastname: Shimono
mesh_terms: D000818:Animals; D017209:Apoptosis; D002465:Cell Movement; D049109:Cell Proliferation; D005456:Fluorescent Dyes; D006706:Homeostasis; D007124:Immunoenzyme Techniques; D020287:In Situ Nick-End Labeling; D008297:Male; D009930:Organic Chemicals; D010513:Periodontal Ligament / Q000166:cytology* / Q000502:physiology*; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D012038:Regeneration; D014090:Tooth Replantation
chemical_list: D005456:Fluorescent Dyes; D009930:Organic Chemicals; C070080:PKH 26; D018809:Proliferating Cell Nuclear Antigen