title: [Effect of TNF-alpha on murine osteoclast differentiation].
abstract: OBJECTIVE
  The purpose of this study was to investigate the effect of TNF-alpha on osteoclast differentiation in primary murine bone marrow cell culture with and without RANKL.
  
  
  METHODS
  M-CSF-dependent bone marrow cells were isolated from 5-6 weeks old mice, and cultured in the presence of M-CSF (25 microg/L) with different concentrations of TNF-alpha (0, 1, 10, 100 microg/L) for 5 days, the formation of TRAP(+) multinucleated cells was observed. These cells were also cultured in the presence of both RANKL (30 microg/L) and M-CSF (25 microg/L) with or without 10 microg/L TNF-alpha for 4, 5, 6 and 9 days. The number of TRAP(+) multinucleated cells and resorption pits on dentine slices were counted under light microscope.
  
  
  RESULTS
  In the absence of RANKL, TNF-alpha was unable to induce osteoclast formation from murine bone marrow precursors. In the presence of RANKL, TNF-alpha augmented osteoclastogenesis and bone resorption, and this effect occurred only on the early stage.
  
  
  CONCLUSIONS
  TNF-alpha enhances RANKL-induced osteoclast formation and function, but cannot substitute for RANKL. TNF-alpha stimulates osteoclast differentiation, but not survival.
authors.affiliation: Department of Paediatric Dentistry, Peking University School of Stomatology, Beijing 100081, China.
authors.forename: Yu-ming
authors.initials: YM
authors.lastname: Zhao
authors.forename: Li-hong
authors.initials: LH
authors.lastname: Ge
authors.forename: Agi E
authors.initials: AE
authors.lastname: Grigoriadis
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology*; D002454:Cell Differentiation / Q000187:drug effects*; D002478:Cells, Cultured; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D051379:Mice; D010010:Osteoclasts / Q000166:cytology*; D053245:RANK Ligand / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D053245:RANK Ligand; D014409:Tumor Necrosis Factor-alpha; D016173:Macrophage Colony-Stimulating Factor