title: [Effect of continuously compressive pressure on the expression of RANKL mRNA in human periodontal ligament cells in vitro].
abstract: OBJECTIVE
  To determine the effect of continuously compressive pressure (CCP) on the expression of receptor activator of nuclear factor kappa B ligand (RANKL) in human periodontal ligament cells (HPDLCs) and to investigate the role of RANKL in alveolar bone rebuilding during orthodontic tooth movement.
  
  
  METHODS
  The primary HPDLCs were isolated from human periodontal ligament by explanting enzymatic digestion with trypsin and collagenase to establish a pressure model. Top-bottom axial pressures (1, 2, and 3 g/cm(2)) were laid on HPDLCs for 0.5, 1.5, 6, 12, 24, and 48 h, respectively. The RANKL expression was identified by the reverse transcription-polymerase chain reaction (RT-PCR) at the mRNA level.
  
  
  RESULTS
  The expression of RANKL mRNA significantly increased in a time-dependent manner (P<0.01), so did the value of pressure, especially in the 2 g/cm(2) group (P<0.05).
  
  
  CONCLUSIONS
  CCP can up-regulate the expression of RANKL mRNA in human periodontal ligament cells.
authors.affiliation: Department of Stomatology, Second Xiangya Hospital, Central South University, Changsha 410011, China. huang_shg@126.com
authors.forename: Sheng-gao
authors.initials: SG
authors.lastname: Huang
authors.forename: Jian-xing
authors.initials: JX
authors.lastname: Zhang
authors.forename: Pei-ying
authors.initials: PY
authors.lastname: Xiong
authors.forename: Ming-lang
authors.initials: ML
authors.lastname: Wang
mesh_terms: D019245:Compressive Strength; D006801:Humans; D010513:Periodontal Ligament / Q000166:cytology / Q000378:metabolism*; D053245:RANK Ligand / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D053246:Receptor Activator of Nuclear Factor-kappa B / Q000235:genetics / Q000378:metabolism*; D013314:Stress, Mechanical
chemical_list: D053245:RANK Ligand; D012333:RNA, Messenger; D053246:Receptor Activator of Nuclear Factor-kappa B