title: Epimedium-derived flavonoids modulate the balance between osteogenic differentiation and adipogenic differentiation in bone marrow stromal cells of ovariectomized rats via Wnt/β-catenin signal pathway activation.
abstract: OBJECTIVE
  To observe the function of wnt/β-catenin signal pathway on the process that epimedium-derived flavonoids (EFs) regulate the balance between osteogenic differentiation and adipogenic differentiation in bone marrow stromal cells of ovariectomized rats, and to provide an experimental evidence for the mechanism of EFs on treating postmenopausal osteoporosis.
  
  
  METHODS
  Bone marrow stromal cells from ovariectomized rats were separated and cultivated in the condition of osteoinductive medium or liquid medium for 15 days. Low- (1 μg/mL), medium- (10 μg/mL) and high- (100 μg/mL) dose EFs were administrated correspondingly. Alkaline phosphatase (ALP) staining, ALP activity determination, oil red O staining and realtime polymerese chain reaction (RT-PCR) were used to determine the effect of EFs on osteogenic differentiation and adipogenic differentiation in bone marrow stromal cells of ovariectomized rats. Moreover, in order to explore the mechanism of EFs on osteogenic differentiation and adipogenic differentiation in bone marrow stromal cells of ovariectomized rats, Dickkopf-related protein 1 (DKK1) was used in the medium group. Enzymelinked immunosorbent assay (ELISA) and RT-PCR were used to determine mRNA levels of β-catenin, low density lipoprotein receptor-related protein 5 (LRP5) and T cell factor (TCF) protein, known as wnt/β-catenin signal pathway related factors.
  
  
  RESULTS
  EFs increased mRNA expression levels of ALP and early osteoblast differentiation factors, such as runt-related transcription factor 2 (Runx2), osteocalcin and collagen I, and decreased mRNA expression levels of fat generation factors, such as peroxisome proliferator activated receptor gamma 2 (PPARγ-2) and CCAAT enhancer-binding protein-α (C/EBPα) in a dose-dependent manner. While osteoblast differentiation factors were down-regulated, fat generation factors were up-regulated when DKK1 was applied. Also EFs up-regulated mRNA expression levels of β-catenin, LRP5 and TCF protein which could be blocked by DKK1.
  
  
  CONCLUSIONS
  EFs regulate the balance between osteogenic differentiation and adipogenic differentiation in bone marrow stromal cells of ovariectomized rats by activating wnt/β-catenin signal pathway, which may be an important molecular mechanism of EFs on treating postmenopausal osteoporosis.
authors.affiliation: Research Institution of Orthopaedics and Traumatology, Zhejiang Traditional Chinese Medical University, Hangzhou 310053, China. xuyingxing5192@126.com
authors.forename: Ying-xing
authors.initials: YX
authors.lastname: Xu
authors.forename: Cheng-liang
authors.initials: CL
authors.lastname: Wu
authors.forename: Yan
authors.initials: Y
authors.lastname: Wu
authors.forename: Pei-jian
authors.initials: PJ
authors.lastname: Tong
authors.forename: Hong-ting
authors.initials: HT
authors.lastname: Jin
authors.forename: Nan-ze
authors.initials: NZ
authors.lastname: Yu
authors.forename: Lu-wei
authors.initials: LW
authors.lastname: Xiao
mesh_terms: D000273:Adipose Tissue / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D001842:Bone and Bones / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects*; D017931:DNA Primers; D004797:Enzyme-Linked Immunosorbent Assay; D034181:Epimedium / Q000737:chemistry*; D005260:Female; D005419:Flavonoids / Q000494:pharmacology*; D005434:Flow Cytometry; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction; D051153:Wnt Proteins / Q000378:metabolism*; D051176:beta Catenin / Q000378:metabolism*
chemical_list: D017931:DNA Primers; D005419:Flavonoids; D051153:Wnt Proteins; D051176:beta Catenin