title: Sodium butyrate stimulates mineralized nodule formation and osteoprotegerin expression by human osteoblasts.
abstract: OBJECTIVE
  Butyric acid (sodium butyrate; BA) is a major metabolic by-product of main periodontopathic bacteria present in subgingival plaque. In the present study, we examined the effects of BA on cell proliferation, alkaline phosphatase (ALPase) activity, mineralized nodule formation, extracellular matrix protein expression, macrophage colony-stimulating factor (M-CSF), and osteoprotegerin (OPG) in normal human osteoblasts.
  
  
  METHODS
  The cells were cultured with 0, 10(-8), 10(-6) or 10(-4)M BA for up to 12 days. Mineralized nodule formation was detected by alizarin red staining, and the calcium content in mineralized nodules was determined using a calcium assay kit. The gene and protein expression levels for type I collagen, bone sialoprotein (BSP), osteopontin (OPN), M-CSF, and OPG were examined using real-time PCR and ELISA, respectively.
  
  
  RESULTS
  Mineralized nodule formation and the calcium content of mineralized nodules were increased by BA in a dose-dependent manner. Cell proliferation and ALPase activity were not affected by the addition of BA. Following the addition of 10(-4)M BA, the expression levels of BSP, OPN, and OPG increased, whereas the expression levels of type I collagen and M-CSF were not markedly affected.
  
  
  CONCLUSIONS
  These results suggest that BA stimulates bone formation by increasing the production of BSP and OPN, whereas it suppresses osteoclast differentiation by increasing the production of OPG by human osteoblasts.
authors.affiliation: Nihon University Graduate School of Dentistry, 1-8-13 Kanda Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Katono
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kawato
authors.forename: Natsuko
authors.initials: N
authors.lastname: Tanabe
authors.forename: Naoto
authors.initials: N
authors.lastname: Suzuki
authors.forename: Takafumi
authors.initials: T
authors.lastname: Iida
authors.forename: Akira
authors.initials: A
authors.lastname: Morozumi
authors.forename: Kuniyasu
authors.initials: K
authors.lastname: Ochiai
authors.forename: Masao
authors.initials: M
authors.lastname: Maeno
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D020148:Butyric Acid / Q000494:pharmacology*; D002113:Calcification, Physiologic / Q000187:drug effects* / Q000502:physiology; D002118:Calcium / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D016173:Macrophage Colony-Stimulating Factor / Q000378:metabolism; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D053244:Osteoprotegerin / Q000378:metabolism*
chemical_list: D016326:Extracellular Matrix Proteins; D053244:Osteoprotegerin; C506030:TNFRSF11B protein, human; D020148:Butyric Acid; D016173:Macrophage Colony-Stimulating Factor; D000469:Alkaline Phosphatase; D002118:Calcium