title: [The effect of ferric ion on the differentiation of osteoclast and bone resorption].
abstract: OBJECTIVE
  To explore the effects of ferric ion on the differentiation from both RAW264.7 and bone marrow macrophages to osteoclast in vitro and bone resorption in vivo.
  
  
  METHODS
  In the presence of 50 ng/ml receptor activator of nuclear factor kappa-B ligand (RANKL), RAW264.7 was treated with ferric ammonium citrate (FAC). The formation of osteoclast was observed by staining of tartrate-resistant acid phosphatase (TRAP) and the TRAP positive cell counted. The expression levels of TRAP, cathepsin-K, nuclear factor of activated T cells c1 (NFATc1) and (receptor activator of NF-κB) RANK were measured by reverse transcription-polymerase chain reaction (RT-PCR).The control and iron overload groups were established by the intraperitoneal injection of normal saline and FAC. In vivo imaging system was employed to determine the bone density of femoral midportion and the fourth lumbar vertebra. After that, the bone marrow cells of femurs were used for osteoclast culture. The serum levels of ferritin, TRAP-5b, RANKL, osteoprotegerin (OPG) and C-terminal cross-linking telopeptide (CTX) were measured by enzyme-linked immunosorbent assay (ELISA).
  
  
  RESULTS
  Ferric ion could stimulate the formation of TRAP positive cells in a dose-dependent manner. The expression levels of TRAP, cathepsin-K and NFATc1 in the FAC treated group were significantly higher those of the control group (P < 0.05) while the expression of RANK showed no statistical difference among these groups (P = 0.967). The bone marrow density of femoral midportion and the fourth lumbar vertebra of the iron-overload group decreased significantly versus the control group. The concentrations of ferritin, TRAP-5b, RANKL and CTX of the iron overload group were markedly higher than those of the control group (P < 0.05). Moreover, the concentration of ferritin showed a positive correlation with TRAP-5b and CTX respectively in the iron-overload group (r = 0.65, r = 0.76, P < 0.05). But no significant differences existed in the concentration of OPG for two groups (P > 0.05).
  
  
  CONCLUSIONS
  Ferric ion may enhance the differentiation of osteoclast in vitro as well as bone resorption in vivo.
authors.affiliation: Department of Orthopedics, Second Affiliated Hospital, Soochow University, Suzhou 215004, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Jia
authors.forename: Yin-feng
authors.initials: YF
authors.lastname: He
authors.forename: Chao
authors.initials: C
authors.lastname: Gao
authors.forename: Hou-bing
authors.initials: HB
authors.lastname: Du
authors.forename: Zhi-yong
authors.initials: ZY
authors.lastname: Hu
authors.forename: Xiao-qing
authors.initials: XQ
authors.lastname: Feng
authors.forename: Bing-yan
authors.initials: BY
authors.lastname: Li
authors.forename: Zeng-li
authors.initials: ZL
authors.lastname: Zhang
authors.forename: You-jia
authors.initials: YJ
authors.lastname: Xu
authors.forename: Hua
authors.initials: H
authors.lastname: Lin
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D001862:Bone Resorption; D002454:Cell Differentiation / Q000187:drug effects*; D002460:Cell Line; D024042:Collagen Type I / Q000378:metabolism; D005290:Ferric Compounds / Q000494:pharmacology*; D007527:Isoenzymes / Q000378:metabolism; D008264:Macrophages / Q000166:cytology / Q000187:drug effects; D051379:Mice; D008813:Mice, Inbred ICR; D050778:NFATC Transcription Factors / Q000378:metabolism; D010010:Osteoclasts / Q000166:cytology / Q000187:drug effects*; D053244:Osteoprotegerin / Q000378:metabolism; D010455:Peptides / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology*; D053245:RANK Ligand / Q000378:metabolism; D000071681:Tartrate-Resistant Acid Phosphatase
chemical_list: D024042:Collagen Type I; D005290:Ferric Compounds; D007527:Isoenzymes; D050778:NFATC Transcription Factors; C494005:Nfatc1 protein, mouse; D053244:Osteoprotegerin; D010455:Peptides; D000644:Quaternary Ammonium Compounds; D053245:RANK Ligand; C506031:Tnfrsf11b protein, mouse; C505689:Tnfsf11 protein, mouse; C052929:collagen type I trimeric cross-linked peptide; D000135:Acid Phosphatase; C000605511:Acp5 protein, mouse; D000071681:Tartrate-Resistant Acid Phosphatase; C013531:ferric ammonium citrate