title: [The effect of continuously compressive press on the shape of cells and expressions of MMP-9,TRAP in human osteoclasts].
abstract: OBJECTIVE
  To investigate the effect of continuously compressive pressure on the function of human osteoclasts.
  
  
  METHODS
  Monocytes were collected from umbilical cord cells, and were cultured for 14 days. alpha-MEM which contains RANKL and M-CSF was used as the culture medium. 100kPa compressive pressure was applied to the mature osteoclasts for 1 hour,2 hours and 3 hours. The shape change was observed. TRAP,MMP-9 enzymes were stained, and measured randomly. The data were analyzed with SPSS12.0 software package for Student's t test.
  
  
  RESULTS
  Compressive pressure made the shape of osteoclasts incline to round. After adding pressure for 1 hour, there was significant difference on the expression of TRAP between pressure group(59.61+/-14.95)and non-pressure group(80.01+/-9.69) (P<0.05). Significant increase expression of MMP-9 occured after 5 hours (P<0.05).
  
  
  CONCLUSIONS
  The changes of shape and levels of functional enzymes show that compressive pressure enhances the bone-absorbing activity. Supported by National Natural Science Foundation of China (Grant No.30471911).
authors.affiliation: Department of Orthodontics, Stomatological Hospital, Xi'an Jiaotong University. Xi'an 710004, Shanxi Province, China. petrelxu@163.com
authors.forename: Hai-Yan
authors.initials: HY
authors.lastname: Xu
authors.forename: Hong
authors.initials: H
authors.lastname: Zhou
authors.forename: Guo-Zhou
authors.initials: GZ
authors.lastname: Rao
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D001862:Bone Resorption; D002478:Cells, Cultured; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D009930:Organic Chemicals; D010010:Osteoclasts / Q000378:metabolism*; D011312:Pressure; D053245:RANK Ligand / Q000378:metabolism; D000071681:Tartrate-Resistant Acid Phosphatase
chemical_list: D007527:Isoenzymes; D009930:Organic Chemicals; D053245:RANK Ligand; C420642:alpha minimal essential medium; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase; D020780:Matrix Metalloproteinase 9