title: Influence of different intensities of vibration on proliferation and differentiation of human periodontal ligament stem cells.
abstract: BACKGROUND
  To understand the effects of low-magnitude, high-frequency (LMHF) mechanical vibration at different intensities on human periodontal ligament stem cell (hPDLSC) proliferation and osteogenic differentiation.
  
  
  METHODS
  The effect of vibration on hPDLSC proliferation, osteogenic differentiation, tenogenic differentiation and cytoskeleton was assessed at the cellular, genetic and protein level.
  
  
  RESULTS
  The PDLSC proliferation was decreased after different magnitudes of mechanical vibration; however, there were no obvious senescent cells in the experimental and the static control group. Expression of osteogenesis markers was increased. The expression of alkaline phosphatase (ALP) and osteocalcin (OCN) mRNA was up-regulated at 0.1 g, 0.3 g, 0.6 g and 0.9 g magnitude, with the peak at 0.3 g. The type I collagen (Col-I) level was increased after vibration exposure at 0.1 g, 0.3 g, and 0.6 g, peaking at 0.3 g. The expression levels of both mRNA and protein of Runx2 and osterix (OSX) significantly increased at a magnitude of 0.1 g to 0.9 g, reached a peak at 0.3 g and then decreased slowly. The scleraxis, tenogenic markers, and mRNA expression decreased at 0.05 g, 0.1 g, and 0.3 g, and significantly increased at 0.6 g and 0.9 g. Compared with the static group, the F-actin stress fibers of hPDLSCs became thicker and clearer following vibration.
  
  
  CONCLUSIONS
  The LMHF mechanical vibration promotes PDLSC osteogenic differentiation and implies the existence of a magnitude-dependent effect of vibration on determining PDLSC commitment to the osteoblast lineage. Changes in the cytoskeleton of hPDLSCs after vibration may be one of the mechanisms of the biological effects.
authors.affiliation: Tianjin Stomatological Hospital of Nankai University, Tianjin, China.
authors.forename: Chunxiang
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Xiangya Stomatology Hospital, Central South University, Changsha, Hunan, China.
authors.forename: Yanqin
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Tianjin Stomatological Hospital of Nankai University, Tianjin, China.
authors.forename: Linkun
authors.initials: L
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Affiliated Hospital of Stomatology, Medical College, Zhejiang University, Hangzhou, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
authors.forename: Yangxi
authors.initials: Y
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
authors.forename: Haiyang
authors.initials: H
authors.lastname: Yu
keywords: magnitude; mechanical vibration; osteogenesis; periodontal ligament stem cells; proliferation