Abstract: Objective To compare the efficacy of different stages of induced BMSCs in repairing bone injury of rabbit, and to find out the most suitable cells for transplantation. Methods BMSCs were isolated, cultured and identified in vitro. After labeled by GFP, BMSCs were induced and 40 rabbits were randomly divided into five groups according to different time of induction: non-induce group (n=5), 3-day group (n=10), 7-day group (n=10), 21-day group (n=10), control group (n=5). The bone injury model of rabbit was established. After successfully modeled for 24 hours, GFP labeled, induced BMSCs were injected into fracture area with the dosage of 3×106 cells/Kg. X-ray exam was carried out and evaluated. Results According to X-ray evaluation criteria, the X-ray score among non-induce group, 7-day group and 21-day group has no difference (P>0.05), but all significantly higher than control group (P<0.01). The X-ray score in 3-day group was higher than 7-day group and 21-day group (P<0.05), and significantly higher than control group (P<0.01). Conclusion BMSCs induced for 3 days turned out to be the most suitable cells for transplantation.

Key words: Bone mesenchymal stem cells, Induction, Transplantation, Fracture