In vivo ectopic osteogenesis of calcium phosphate cement with rhBMP-2/rhbFGF

Objective: Basic fibroblast growth factor (bFGF) and bone morphogenetic proteins-2 (BMP-2) are actively pursued for stimulation of bone formation. This study aimed to observe the osteogenesis of porous calcium phosphate cement (PCPC) loaded with bone marrow stromal cells (BMSCs) induced by rhBMP-2 and rhbFGF in a nude mice model.

Methods: BMSCs were obtained from the iliac crest of a beagle dog (1 year old, 15-20kg) and cultured, expanded, induced in vitro with basic culture medium containing (1)100ng/ml rhBMP-2,(2) 50ng/ml rhbFGF,(3) 100ng/ml rhBMP-2+50ng/ml rhbFGF. The BMSCs were seeded in the PCPC scaffolds and implanted subcutaneously into the backs of nude mice. Implantation of PCPC alone was used as control. At 4, 8 and 12 weeks after implantation, the specimens were harvested and the osteogenetic activity was evaluated by gross and histological examination. The area of bone was quantified and analyzed by means of a Zeiss Axioplan 2 imaging analysis system. Results: The bone formation was presented in all tissue-engineered implants at the 4th week after implantation in vivo ectopia. At 12 weeks after implantation, much more mature bone had formed in group 1 than the other groups(P<0.05). The endochondral bone formation pattern was observed. Conclusion: rhBMP-2/rhbFGF could increase new bone formation and acted synergistically to improve osteogenetic activity of PCPC/BMSCs. This study suggests that rhBMP-2/rhbFGF can be used as osteoinductive substances and PCPC can be used as a bone tissue engineering scaffold .