Abstract: Objective To construct an animal model of fetal bone mesenchymal stem cells with rabbit. Methods Four pregnant rabbits (pregnancy=3 weeks) were treated with artificial fertilization, and 20 fetal rabbits were obtained with cesarean section. Fetal rabbit bone marrow was harvested and cultured in vitro. The cell morphology, growth curve, cloning efficiency and trilinear differentiation of BMSCs of passage 3 were observed. Cryopreserved primary cells were recovered after 30 days, the growth curve of passage 3 was measured to compare with that non-cryopreserved. With scanning electron microscope, the fetal cells in β-TCP cell-material compound were observed. Finally, after osteogenic induction, the BMSCs-β-TCP compound was implanted into the nude mice subcutaneously and the histological results of tissue-engineered bone at 1, 3, 6 months were observed. Results The BMSCs from fetal rabbit demonstrated a spindle-shaped morphology. After several passages, the morphology and growth curve remained almost the same. The calcium, fat and mucopolysaccharide were witnessed in trilinear differentiation. After cryopreserved for 30 days, the growth curve of passage 3 showed few changes compared with non-cryopreserved. According to SEM, the fetal cells tightly attached to the materials and extended well after seeded on β-TCP for 7 days. The fresh bone tissue were all observed at different time point by histological staining. Conclusion Rabbit as animal model can isolate and procure the fetal BMSCs and has good osteogenic ability in vivo. And it can be the new choice of the animal model for fetal bone mesenchymal stem cells.

Key words: Bone marrow mesenchymal stem cells, Seed cells, Bone tissue engineering, Rabbit