Dynamic expression of DKK1 protein in the process whereby Epimedium-derived flavonoids up-regulate osteogenic and down-regulate adipogenic differentiation of bone marrow stromal cells in ovariectomized rats.
OBJECTIVE
To observe the dynamic expression of DKK1 protein in the process whereby Epimedium-derived flavonoids (EFs) regulate the balance between osteogenic and adipogenic differentiation of bone marrow stromal cells in ovariectomized rats, and to provide experimental evidence for the mechanism of EFs in the treatment of postmenopausal osteoporosis.


METHODS
Bone marrow stromal cells from ovariectomized rats were separated and cultivated in osteoinductive or liquid medium for 15 days in vitro. EFs (10 µg/mL) were applied to both cultures. Alkaline phosphatase (ALP) staining, ALP activity determination, Oil Red O staining and fluorescence quantitative polymerase chain reaction were used to determine the influence of EFs on osteogenic and adipogenic differentiation of bone marrow stromal cells in ovariectomized rats. Moreover, in order to explore the exact mechanism of EFs on osteogenic and adipogenic differentiation of bone marrow stromal cells in ovariectomized rats, enzyme linked immunosorbent assay was used to determine the dynamic expression of DKK1 protein in this process.


RESULTS
EFs increased activity of ALP and mRNA expression of Runx2 (early osteoblast differentiation factor) and decreased mRNA expression of PPARγ-2 (key factor of fat generation). Importantly, EFs down-regulated expression of DKK1 protein in an osteogenic induction medium and inhibited up-regulation of DKK1 protein in an adipogenic induction medium.


CONCLUSIONS
EFs regulate the balance between osteogenic and adipogenic differentiation of bone marrow stromal cells in ovariectomized rats by down-regulating expression of DKK1 protein. This may be an important molecular mechanism of EFs in the context of treatment of postmenopausal osteoporosis.
The First Clinical Medical College, Zhejiang Traditional Chinese Medical University, China.
Ying-xing
YX
Xu
Bing
B
Xu
Cheng-liang
CL
Wu
Yan
Y
Wu
Pei-jian
PJ
Tong
Lu-wei
LW
Xiao
D050156:Adipogenesis / Q000187:drug effects*; D000818:Animals; D001854:Bone Marrow Cells / Q000187:drug effects*; D050659:Core Binding Factor Alpha 1 Subunit / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D034181:Epimedium / Q000737:chemistry; D005260:Female; D005419:Flavonoids / Q000494:pharmacology*; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D059630:Mesenchymal Stem Cells / Q000187:drug effects*; D010012:Osteogenesis / Q000187:drug effects*; D010052:Ovariectomy; D047495:PPAR gamma / Q000378:metabolism; D051381:Rats; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods
D050659:Core Binding Factor Alpha 1 Subunit; C531384:Dkk1 protein, rat; D005419:Flavonoids; D036341:Intercellular Signaling Peptides and Proteins; D047495:PPAR gamma; C493717:Runx2 protein, rat