Osteogenic effects of D+beta-3,4-dihydroxyphenyl lactic acid (salvianic acid A, SAA) on osteoblasts and bone marrow stromal cells of intact and prednisone-treated rats.
OBJECTIVE
Previous studies have shown that D(+)beta-3,4-dihydroxyphenyl lactic acid (salvianic acid A, SAA) has anabolic effects on prednisone (GC)-induced osteoporosis in rats. The current study aims to investigate the molecular mechanism of SAA's impact on osteogenesis and adipogenesis in bone marrow stromal cells in intact and GC-treated rats.


METHODS
For in vitro study, newborn rat calvaria osteoblasts (rOBs) and rat bone marrow stromal cells (rMSCs) were isolated, identified and cultured with SAA at different concentrations to evaluate SAA's influence on osteogenesis and adipogenesis. In addition, 3-month-old Sprague-Dawley (SD) male rats were treated with distilled water, prednisone alone (3.0 mgxkg(-1)xd(-1)) or prednisone (3.0 mgxkg(-1)xd(-1)) and SAA (25 mgxkg(-1)xd(-1)) for 45 d. At the end point, the different groups of rMSCs were isolated by density-gradient centrifugation and cultured.


RESULTS
(1) At 0.1-10.0 mg/L, SAA increased ALP activity, type I collagen (Coll-I) mRNA and OPG mRNA expression and stimulated nodule mineralization of rOBs. SAA (0.5 mg/L) also significantly increased the ALP activity of rMSCs without a need for osteogenesis-inducing medium. At 5.0 mg/L, SAA decreased the number of adipocytes with less lipid droplet formation from the rMSCs, which typically undergo adipocyte induction. (2) Coll-I expression was markedly decreased, whereas lipoprotein lipase (LPL) mRNA expression increased by 98% when compared with the first generation of rMSCs in GC-treated rats. The SAA-treated rats demonstrated an over 2-fold increase in Coll-I expression when compared with intact rats and further showed a significant decrease in LPL expression when compared with GC-treated rats. When rMSCs were co-cultured with SAA (0.5 mg/L) in vitro, SAA did not affect Coll-I and LPL gene expression in intact rats but significantly increased Coll-I and decreased LPL gene expression in GC-treated rats.


CONCLUSIONS
SAA protected bone from GC-induced bone marrow impairment by stimulating osteogenesis and depressing adipogenesis in bone marrow stromal cells both in vivo and in vitro. The data indicated that aqueous extract of Salvia miltiorrhiza, which include SAA, may serve as an active anabolic agent and a useful therapeutic strategy for the treatment of GC-associated osteoporosis.
Cui
Liao
L
Department of Pharmacology, Guangdong Medical College, Zhanjiang, China. cuiliao@163.com
Liu
Yu-Yu
YY
Wu
Tie
T
Ai
Chun-Mei
CM
Chen
Huai-Qing
HQ
D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D002109:Caffeic Acids / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D002478:Cells, Cultured; D024042:Collagen Type I / Q000235:genetics / Q000378:metabolism; D004365:Drugs, Chinese Herbal / Q000494:pharmacology; D005938:Glucocorticoids / Q000494:pharmacology*; D007773:Lactates / Q000494:pharmacology*; D008071:Lipoprotein Lipase / Q000235:genetics / Q000378:metabolism; D008297:Male; D015394:Molecular Structure; D015675:Osteocalcin / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects*; D010936:Plant Extracts / Q000737:chemistry; D011241:Prednisone / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D027544:Salvia / Q000737:chemistry; D017154:Stromal Cells / Q000166:cytology / Q000187:drug effects* / Q000502:physiology
D002109:Caffeic Acids; D024042:Collagen Type I; D004365:Drugs, Chinese Herbal; D005938:Glucocorticoids; D007773:Lactates; D010936:Plant Extracts; D015675:Osteocalcin; C066201:salvianolic acid A; D008071:Lipoprotein Lipase; D000469:Alkaline Phosphatase; D011241:Prednisone