[Osteogenic differentiation of murine yolk sac mesenchymal stem cells in vitro].
OBJECTIVE
To investigate the potential of yolk sac mesenchymal stem cells in osteogenic differentiation.


METHODS
Murine yolk sacs were harvested on day 8.5 postcoitus, yolk sac cells were obtained after the yolk sacs were digested by 0.1% type I collagenase for 1 hour, the non-adherent cells were removed after being cultured for 1 hour. The adherent cells were cultured in DMEM containing of 5 ng/ml bFGF and 15% FBS, and passaged when they became subconfluent. The morphologic characteristics, and AKP, BMP-2, as well as type I, III collagen of the yolk sac adherent cells were observed and tested. The attached cells were treated with 10(-8) mol/L dexamethasone, 10 mmol/L beta-glycerophosphate, and 50 micrograms/ml vitamin C at passage 4. Alternations of morphological characteristic, AKP activity, collagen of type I, III and mineralization were detected.


RESULTS
Pure mesenchymal stem cells which were of spindle shape, uniform in size, positive in type I, III collagen staining and weak positive in AKP activity could be induced to pleomorphism osteoblast-like cells in vitro. The cells were transformed from spindle shape to polygonal cells which were positive in type I collagen, negative in type III collagen, strong positive in BMP-2, and positive in Von Kossa's stain at week 8. The polygonal cells could form nodular structure and their AKP activity was increased. All these were coincidence with the characters of osteoblast.


CONCLUSIONS
Yolk sac mesenchymal stem cell can be purified and induced to osteoblast in vitro.
Zhao
Zi-ping
ZP
Department of Orthopaedics, Third Xiang Ya Hospital of Central South University, Changsha 410013, China. zhaoziping@cmmail.com
Na
Xiao-dong
XD
Yang
Hui-fang
HF
Zhou
Jiang-nan
JN
D000469:Alkaline Phosphatase / Q000096:biosynthesis; D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000096:biosynthesis; D002454:Cell Differentiation; D002478:Cells, Cultured; D005260:Female; D008648:Mesoderm / Q000166:cytology; D051379:Mice; D010006:Osteoblasts / Q000166:cytology*; D010012:Osteogenesis; D013234:Stem Cells / Q000166:cytology*; D015017:Yolk Sac / Q000166:cytology*
D019485:Bone Morphogenetic Proteins; D000469:Alkaline Phosphatase