Objective      To construct a bone defect-induced membrane model and to discuss the osteogenic activity of the bone induced membrane on inactivated bone graft.        Methods      A radial defect model was built with 32 New Zealand rabbits. Polymethyl methacrylate (PMMA) bone cement spacer was inserted into the defect to induce membrane. After 6 and 8 weeks

8 rabbits (4 for each time) were sacrificed and bone induced membranes were taken out to test bone morphogenetic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF) levels and to perform HE staining of sections

with rabbit subcutaneous tissue as control. Bone cement was taken out from the other 24 rabbits in 6 weeks after implantation for secondary operation

including 3 groups

an experimental group [keeping the induced membrane in situ and implanting autologous iliac inactivated with high temperature water (100 ℃ 30 min)]

a model group (keeping the induced membrane in situ)

and a control group (removing the induced membrane and implanting autologous iliac inactivated with high temperature water). Radiological and histological evaluation of the new bone formation was done at 8 and 12 weeks.        Results      (1) BMP-2 and VEGF levels in the induced membrane were 437.40±20.75 pg/mL and 362.33±38.85 pg/mL

respectively

at 6 weeks and 346.67±30.05 pg/mL and 233.84±18.20 pg/mL

respectively

at 8 weeks

higher than those of the subcutaneous tissue (P0.05)

while endochondral ossification was observed in induced membrane slice. (2) Radiological detection at 8 and 12 weeks after the secondary operation indicated that bone formation was more in the experimental group than in the model group and the control group (P0.01). There was a little callus formation in the model group

while the control group had no bone formation. (3) Histological detection at 8 and 12 weeks after the secondary operation indicated that bone formation was more in the experimental group than in the model group and the control group (P0.01). Only fiber connection in the control group was observed

without bone cells and cartilage cells.        Conclusion      Bone induced membrane

providing mesenchymal stem cells and growth factors

can promote the reconstruction of bone defects by inactivated bone grafts.