title: The anti-osteoporotic effect of Yijung-tang in an ovariectomized rat model mediated by inhibition of osteoclast differentiation.
abstract: BACKGROUND
  Yijung-tang (YJ), a traditional Asian medicine, is used to treat various diseases. However, its anti-osteoporotic effect and mechanism of action remain unclear. The aim of the present study was to evaluate the anti-osteoporotic effect of YJ in ovariectomized (OVX) rats.
  
  
  METHODS
  Sprague-Dawley rats were divided into five groups as follows: sham-operated, ovariectomized (OVX), OVX rats treated with 100 g/kg/day 17-estradiol, and OVX rats treated with 0.3 and 1.0 g/kg/day YJ for 12 weeks. Trabecular bone mineral density (BMD) and bone microarchitecture were evaluated by microcomputed tomography. The effects of YJ on osteoblast and osteoclast formation were also investigated in an in vitro model using primary murine bone marrow-derived macrophages and murine calvarial preosteoblasts. mRNA expression of osteoclast differentiation-related genes was measured by real-time quantitative reverse transcription-polymerase chain reaction. Activation of the mitogen-activated protein kinases and nuclear factor-κB (NF-κB) were determined by Western blot.
  
  
  RESULTS
  The decrease of BMD and destruction of bone microarchitecture were significantly reduced in the OVX-induced osteoporosis rat model after 12 weeks of YJ treatment. The anti-osteoporotic effect of YJ on bone loss was due to inhibition of osteoclast differentiation through down-regulation of the NF-κB pathway. In addition, YJ suppressed the induction of nuclear factor of activated T-cells, cytoplasmic 1 and c-Fos following receptor activator of nuclear factor kappa-B ligand stimulation.
  
  
  CONCLUSIONS
  These results suggest that YJ possess potent anti-osteoporotic activity in OVX rats and may be a useful remedy for the treatment of postmenopausal osteoporosis.
authors.affiliation: KM-Based Herbal Drug Research Group, Korea Institute of Oriental Medicine, Daejeon 305-811, Republic of Korea.
authors.forename: Taesoo
authors.initials: T
authors.lastname: Kim
authors.forename: Hyunil
authors.initials: H
authors.lastname: Ha
authors.forename: Ki-Shuk
authors.initials: KS
authors.lastname: Shim
authors.forename: Won-Kyung
authors.initials: WK
authors.lastname: Cho
authors.forename: Jin Yeul
authors.initials: JY
authors.lastname: Ma
mesh_terms: D000818:Animals; D015519:Bone Density / Q000187:drug effects; D050071:Bone Density Conservation Agents / Q000494:pharmacology / Q000627:therapeutic use*; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D004365:Drugs, Chinese Herbal / Q000494:pharmacology / Q000627:therapeutic use*; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000187:drug effects / Q000502:physiology; D050778:NFATC Transcription Factors / Q000378:metabolism; D010010:Osteoclasts / Q000166:cytology / Q000187:drug effects*; D010024:Osteoporosis / Q000517:prevention & control*; D010052:Ovariectomy; D008517:Phytotherapy; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D053245:RANK Ligand; D051381:Rats; D017207:Rats, Sprague-Dawley; D055114:X-Ray Microtomography
chemical_list: D050071:Bone Density Conservation Agents; D004365:Drugs, Chinese Herbal; D050778:NFATC Transcription Factors; D016760:Proto-Oncogene Proteins c-fos; D053245:RANK Ligand; C582768:yijung-tang