| Objective:To study the survival and distribution of allogenic BMSCs after implantation into other rabbits. To evaluate osteogenetic effectiveness of gelatin sponge mixed with BMSCs of rabbit induced by LMP-1 in radial defects repair of rabbits, to lay the foundation for further application. Methods:The BMSCs of New Zealand white rabbits were collected,cultured,purified and amplified,then they were induced by LMP-1 .Adherence and proliferation were observed. Then they were cultured with gelatin sponge and observed under scanning electron microscope. ALP level were tested to observe bone formation ability comparing with untransfected group. Then they were planted into ectogluteus of other rabbits in order to observe the survival and distribution of BMSCs. Model of radial bone defects (15 mm )of rabbits was established. 48 rabbits were divided into 4 groups,group A (LMP-1 induced BMSCs/GS group),group B (BMSCs/GS group),group C (GS group),group D (untreated group).Roentgenographic,histologic,biomechanics,palpation of the animals were examined at 4w,8w,12w after surgery to evaluate osteogenetic effectiveness.We used Tsuchida H and Hashimoto J score system to give a mark in the roentgenographic examination. Max load,compressive and Young's modulus were observed. Results were processed using SPSS11.0 and we considered the difference was significant if P value did not exceed 0.05 .Results:Adherence and proliferation of BMSCs were not impacted after induced by LMP-1. ALP test shew LMP-1 induced group was higher than untransfected group and the difference was significant .The BMSCs marked with eGFP could live for 3 weeks. At 4th week,radial bone defects healed in group A.The quantity of bone formation decreased from group B to D. In group C and D,no one rabbit healed at 12th week.Score results shew P value between group A and groupB did not exceed 0.05.The results had significant difference. Palpation shew harden bony tissue can be touched in 4w in group A .In group B bony tissue can be touched only in the end of bone. In 12w, group C and D ,bone did not healed in any sample. Histologic observation shew that in group A ,there were many osteoblast ,a few cartilage cells, and bone lacuna in 4w.In 8w, osteocyte were mature, and bone trabecula can be seen. In 12w, bone trabecula were mature, bone marrow cell can be seen. in group B ,there were many cartilage cells and fibrous osteotylus in 4w. In 8w, woven bone and bone trabecula appeared. In 12w, bone trabecula and cavitas medullaris increased, but there were few bone marrow cells in cavitas medullaris. Biomechanics experiment shew in 12w the max load of group A,B and C were 85.7,68.3 and 105.9N; compressive intensity were 7.4,6.1,9.2Mpa,and the Young's modulus were 189.5,136.1,209.1Gpa. Each index of group A and B was lower than that of the opposite side normal control group. But the max load,compressive intensity could reach 80% of control group and Young's modulus could reach 90% of control group.Conclusion:1,GS mixed with BMSCs induced by LMP-1 can repair 1.5 cm radial defects in rabbits.2,In 12w, the biomechanical strength get close to nomal ,and can satisfy physiological need.
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