title: Impact of titanium ions on osteoblast-, osteoclast- and gingival epithelial-like cells.
abstract: OBJECTIVE
  To investigate the effects of titanium (Ti) ions on the cell viability, the cell differentiation and the gene expressions related to bone resorption including Receptor Activator of NF-kappaB Ligand (RANKL) and Osteoprotegerin (OPG) in the tissues around dental implants, the osteoblast-, osteoclast-, and gingival epithelial-like cells were exposed to Ti ions.
  
  
  METHODS
  An MTS assay was carried out to evaluate the viabilities of osteoblast-like MC3T3-E1, osteoclast-like RAW264.7 and epithelial cell-like GE-1 cells. The gene expressions in these cells were analyzed by the use of RT-PCR and real-time quantitative RT-PCR.
  
  
  RESULTS
  Ti ions in the concentration range 1-9 ppm had little effect on the viabilities of MC3T3-E1, RAW264.7 and GE-1, whereas 20 ppm Ti ions significantly decreased the viabilities of all cells. Analyses of RT-PCR and real-time quantitative RT-PCR data revealed that Ti ions at 9 ppm remarkably inhibited the expressions of Runx2, Osterix and type I collagen in MC3T3-E1. In RAW264.7, Ti ions showed no effects on the levels of mRNAs for TRAP and cathepsin K enhanced by RANKL. Ti ions at the range of 1-9 ppm showed no effects on the levels of mRNAs for RANKL and OPG in GE-1, while Ti ions at 9 ppm enhanced the expression of these genes in MC3T3-E1.
  
  
  CONCLUSIONS
  These results, taken together, suggested that Ti ions show the biological effects, both on the viabilities of osteoblast and osteoclast and on the differentiation of either the osteoblastic or osteoclastic cells, which may influence the prognosis of dental implants.
authors.affiliation: Department of Oral Biology and Engineering, Division of Oral Health Science, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Mine
authors.forename: Seicho
authors.initials: S
authors.lastname: Makihira
authors.forename: Hiroki
authors.initials: H
authors.lastname: Nikawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Murata
authors.forename: Ryuji
authors.initials: R
authors.lastname: Hosokawa
authors.forename: Aya
authors.initials: A
authors.lastname: Hiyama
authors.forename: Sumiyo
authors.initials: S
authors.lastname: Mimura
mesh_terms: D000818:Animals; D016723:Bone Remodeling / Q000187:drug effects; D001862:Bone Resorption / Q000235:genetics; D002454:Cell Differentiation / Q000187:drug effects* / Q000235:genetics; D002470:Cell Survival / Q000187:drug effects*; D002478:Cells, Cultured; D015921:Dental Implants; D003864:Depression, Chemical; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000166:cytology*; D015870:Gene Expression / Q000187:drug effects; D005881:Gingiva / Q000166:cytology*; D007477:Ions; D051379:Mice; D010006:Osteoblasts / Q000166:cytology*; D010010:Osteoclasts / Q000166:cytology*; D053244:Osteoprotegerin; D053245:RANK Ligand; D014025:Titanium / Q000009:adverse effects*
chemical_list: D015921:Dental Implants; D007477:Ions; D053244:Osteoprotegerin; D053245:RANK Ligand; D014025:Titanium