Ginsenoside Rg1 promotes bone marrow stromal cells proliferation via the activation of the estrogen receptor-mediated signaling pathway.
OBJECTIVE
To investigate the possible mechanisms of ginsenoside Rg1 promoting bone marrow stromal cell (BMSC) proliferation.


METHODS
BMSC were isolated from bone marrow of Sprague-Dawley rats and maintained in vitro. After stimulation with 1 micromol/L ginsenoside Rg1 for the indicated time, the proliferation ability of BMSC were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide and [3H]-thymidine incorporation assays. The estrogen receptor (ER) binding activity of BMSC was determined by a specific ER antagonist and an ER binding assay. Furthermore, the influence of ginsenoside Rg1 on the expression of ERalpha was investigated by RT-PCR and Western blotting assays.


RESULTS
BMSC proliferation stimulated by 1 micromol/L ginsenoside Rg1 can be completely blocked by 1 micromol/L ER antagonist ICI 182, 780, or ERalpha- specific antagonist methylpiperidinopyrazole. Moreover, Rg1 failed to displace the specific binding of [3H]17beta-estradiol to BMSC cell lysates, suggesting that no direct interaction of Rg1 with the ER is needed for its estrogenic effects. In addition, 1 micromol/L Rg1 had no effects on the expression of ERalpha in either the mRNA or protein levels.


CONCLUSIONS
Our results indicate that ERalpha is essential for mediating the effects of Rg1 on stimulating BMSC proliferation, which might involve the ligand/receptor-independent activation of ERalpha.
Lu
Xin-zheng
XZ
Department of Cardiology, First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China. xzlu@njmu.edu.cn
Wang
Jun-hong
JH
Wu
Xin
X
Zhou
Lei
L
Wang
Li
L
Zhang
Xiao-wen
XW
Cao
Ke-jiang
KJ
Huang
Jun
J
D000818:Animals; D001854:Bone Marrow Cells / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects*; D047628:Estrogen Receptor alpha / Q000096:biosynthesis / Q000187:drug effects; D036145:Ginsenosides / Q000494:pharmacology*; D008297:Male; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D011960:Receptors, Estrogen / Q000187:drug effects*; D015398:Signal Transduction / Q000187:drug effects*; D017154:Stromal Cells / Q000187:drug effects*; D013778:Tetrazolium Salts; D013844:Thiazoles; D013936:Thymidine / Q000378:metabolism
D047628:Estrogen Receptor alpha; D036145:Ginsenosides; D012333:RNA, Messenger; D011960:Receptors, Estrogen; D013778:Tetrazolium Salts; D013844:Thiazoles; C022616:thiazolyl blue; C035054:ginsenoside Rg1; D013936:Thymidine