title: Dental pulp cells promote the expression of receptor activator of nuclear factor-κB ligand, prostaglandin E2and substance P in mechanically stressed periodontal ligament cells.
abstract: OBJECTIVE
  This study investigated the expression of receptor activator of nuclear factor-κB ligand (RANKL) in periodontal ligament (PDL) cells co-cultured with dental pulp (DP) cells following mechanical stress in vitro. Furthermore, the expression of prostaglandin (PG) E2and substance P (SP) by the PDL cells and by the DP cells were also examined.
  
  
  METHODS
  PDL and DP cells were obtained from 10 rats. The experimental group consisted of PDL cells subjected to centrifugal force as mechanical stress and co-cultured with DP cells. The 3 control groups of PDL cells were: 1) PDL cells without mechanical stress, 2) PDL cells treated with mechanical stress and 3) PDL cells co-cultured with DP cells. The 2 control groups of DP cells were: 1) DP cells without mechanical stress and 2) DP cells co-cultured with PDL cells. In each group, both cells were examined at day 1 and day 3, and mRNA levels of RANKL by PDL cells were analyzed using Real time quantitative Reverse Transcription (RT)-PCR. Furthermore, RANKL expression was observed using Immunofluorescence staining. PGE2and SP expression levels by PDL cells and DP cells were characterized by ELISA analysis.
  
  
  RESULTS
  The expression of RANKL by PDL cells under mechanical stress increased by co-culture with DP cells. PGE2and SP expressions were increased in the group of PDL cells subjected to mechanical stress and co-cultured with DP cells.
  
  
  CONCLUSIONS
  DP cells may facilitate the expression of RANKL in PDL cells under mechanical stress via PGE2and SP.
authors.affiliation: Department of Orthodontics, Tokyo Dental College, 2-9-18, Misaki-cho, Chiyoda-ku, Tokyo, 101-0061, Japan. Electronic address: morikawataiki@tdc.ac.jp.
authors.forename: Taiki
authors.initials: T
authors.lastname: Morikawa
authors.affiliation: Department of Clinical Pathophysiology, Tokyo Dental College, 2-9-18, Misaki-cho, Chiyoda-ku, 101-0061, Tokyo, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Matsuzaka
authors.affiliation: Department of Clinical Pathophysiology, Tokyo Dental College, 2-9-18, Misaki-cho, Chiyoda-ku, 101-0061, Tokyo, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Nakajima
authors.affiliation: Department of Orthodontics, Tokyo Dental College, 2-9-18, Misaki-cho, Chiyoda-ku, Tokyo, 101-0061, Japan.
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Yasumura
authors.affiliation: Department of Orthodontics, Tokyo Dental College, 2-9-18, Misaki-cho, Chiyoda-ku, Tokyo, 101-0061, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Sueishi
authors.affiliation: Department of Clinical Pathophysiology, Tokyo Dental College, 2-9-18, Misaki-cho, Chiyoda-ku, 101-0061, Tokyo, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Inoue
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D018920:Coculture Techniques; D016207:Cytokines / Q000096:biosynthesis / Q000378:metabolism; D003782:Dental Pulp / Q000166:cytology* / Q000000981:diagnostic imaging / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D004847:Epithelial Cells / Q000378:metabolism; D008297:Male; D018613:Microscopy, Confocal; D010513:Periodontal Ligament / Q000166:cytology* / Q000378:metabolism*; D011453:Prostaglandins / Q000096:biosynthesis*; D053245:RANK Ligand / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D013314:Stress, Mechanical; D013373:Substance P / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D016207:Cytokines; D011453:Prostaglandins; D053245:RANK Ligand; D012333:RNA, Messenger; D013373:Substance P
keywords: Co-culture; Cytokines; Dental pulp cells; Mechanical stress; Periodontal ligament cells