In vitro and In vivo Osteogenic Induction of Mesenchymal Stem Cells from Rabbit Bone Marrow

Jung, Eun Jung; Yoon, Taek Rim; Song, Eun Kyoo; Kim, Soo Hyun

Abstract

PURPOSE
The aim of this study was to analyze the osteogenic effect of cultured rabbit mesenchymal stem cells(MSCs).
MATERIALS AND METHODS
MSCs were obtained from rabbit femur and were cultured in a Dulbecco's Modified Eagle's Medium(DMEM) with beta-glycerophosphatate, L-ascorbic acid, and dexamethasone to proliferate and differentiate into osteoprogenitor cells until 12 weeks. The expression of osteogenic markers was detected by reverse transcription-polymerase chain reaction(RT-PCR) and the release of osteocalcin was measured by Enzyme-linked Immunosorbent Assay(ELISA). MSCs that were cultured on the porous poly-L-lactic-co-glycolic acid(PLGA) scaffold were implanted into athymic nude mouse to observe the osteogenic activity.
RESULTS
As the time, we observed osteoblastic-like cells on the culture flask. Mineralized nodules were observed at 3-4 weeks. Osteogenic markers such as osteopontin, osteonectin, type I collagen, and alkaline phophatase were all identified at 2 weeks. But, expression of osteocalcin was only detected after cells differentiation. The amount of osteocalcin which is a specific protein in osteoblast, increased gradually from 2 weeks until 7 weeks. Scanning electron microscopy revealed that the MSCs were well adhered and proliferated within the PLGA scaffold. Immature bone was identified after 10 weeks in the histological examination of transplanted cell-scaffold composit.
CONCLUSION
Our results demonstrate gradual differentiation of MSCs into osteoblastic cells. The adhesion and proliferation of the cells within the biodegradable scaffold represents the possibility of bone formation using cell-scaffold composites.