title: Effects of mechanical vibration on proliferation and osteogenic differentiation of human periodontal ligament stem cells.
abstract: OBJECTIVE
  Paradental tissues (alveolar bone, periodontal ligament (PDL), and gingiva) have the capacity to adapt to their functional environment. The principal cellular elements of the PDL play an important role in normal function, regeneration of periodontal tissue and in orthodontic treatment. Recently, several studies have shown that low-magnitude, high-frequency (LMHF) mechanical vibration can positively influence bone homeostasis; however, the mechanism and optimal conditions for LMHF mechanical vibration have not been elucidated. It has been speculated that LMHF mechanical vibration stimulations have a favourable influence on osteocytes, osteoblasts and their precursors, thereby enhancing the expression of osteoblastic genes involved in bone formation and remodelling. The objective of this study was to test the effect of LMHF mechanical vibration on proliferation and osteogenic differentiation of human PDL stem cells (PDLSCs).
  
  
  METHODS
  Human PDLSCs were isolated from premolar teeth and randomized into vibration (magnitude: 0.3g; frequency: 10-180 Hz; 30 min/24h) and static cultures. The effect of vibration on PDLSC proliferation, differentiation and osteogenic potential was assessed at the genetic and protein level.
  
  
  RESULTS
  After LMHF mechanical vibration, PDLSC proliferation was decreased; however, this was accompanied by increased markers of osteogenesis in a frequency-dependent manner. Specifically, alkaline phosphatase activity gradually increased with the frequency of vibration, to a peak at 50 Hz, and the level of osteocalcin was significantly higher than control following vibration at 40 Hz, 50 Hz, 60 Hz, 90 Hz and 120 Hz. Levels of Col-I, Runx2 and Osterix were significantly increased by LMHF mechanical vibration at frequencies of 40 Hz and 50 Hz.
  
  
  CONCLUSIONS
  Our data demonstrates that LMHF mechanical vibration promotes PDLSC osteogenic differentiation and implies the existence of a frequency-dependent effect of vibration on determining PDLSC commitment to the osteoblast lineage.
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, PR China.
authors.forename: Chunxiang
authors.initials: C
authors.lastname: Zhang
authors.forename: Ji
authors.initials: J
authors.lastname: Li
authors.forename: Linkun
authors.initials: L
authors.lastname: Zhang
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhou
authors.forename: Weiwei
authors.initials: W
authors.lastname: Hou
authors.forename: Huixin
authors.initials: H
authors.lastname: Quan
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Li
authors.forename: Yangxi
authors.initials: Y
authors.lastname: Chen
authors.forename: Haiyang
authors.initials: H
authors.lastname: Yu
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000704:Analysis of Variance; D015153:Blotting, Western; D002454:Cell Differentiation / Q000502:physiology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D050659:Core Binding Factor Alpha 1 Subunit / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007150:Immunohistochemistry; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D015675:Osteocalcin / Q000378:metabolism; D010012:Osteogenesis / Q000502:physiology*; D010446:Peptide Fragments / Q000378:metabolism; D010513:Periodontal Ligament / Q000166:cytology*; D012333:RNA, Messenger / Q000378:metabolism; D011897:Random Allocation; D060888:Real-Time Polymerase Chain Reaction; D000076182:Sp7 Transcription Factor; D013234:Stem Cells / Q000166:cytology*; D014157:Transcription Factors / Q000378:metabolism; D014732:Vibration
chemical_list: D050659:Core Binding Factor Alpha 1 Subunit; D010446:Peptide Fragments; D012333:RNA, Messenger; C493709:RUNX2 protein, human; D000076182:Sp7 Transcription Factor; C478163:SP7 protein, human; D014157:Transcription Factors; D015675:Osteocalcin; D000469:Alkaline Phosphatase; C471083:Col-1 peptide, human; D020778:Matrix Metalloproteinase 2