Objective       To study the difference in ectopic revascularization between autogenous bone graft and allograft from large segment tibia of rabbits at different time points.        Methods       With random grouping method

60 healthy adult Chinese rabbits (6 months of age

2.5±0.5 kg) were divided into experimental group (allograft group) and control group (autograft group)

30 rabbits in each group. Another 10 rabbits were allograft bone donor. In the experimental group

1.5 cm long rabbit tibial allograft was implanted into spatium intermusculare between the musculus rectus femoris and medial vastus muscle of the rabbit around the saphenous artery and was fastened to the femur by 1.0 Kirschner-wire. In the control group

autologous tibias were used. At 4

8 and 12 weeks after operation

the postmortem specimens were examined and immunohistochemistry was used to test the expression of vascular endothelial growth factor (VEGF) and CD34 of transplanted bone tissue.        Results       VEGF mainly existed in osteoblasts

chondrocytes

and undifferentiated mesenchymal cells as well as around new vessels. CD34 primarily existed in the endothelial cells with Haversian canal as distribution center. Compared with the control group

the expression level of the VEGF in the experimental group at 4 and 12 weeks after operation was not statistically different (4.50±2.01  vs  5.50±1.35

P0.05; 4.10±1.52  vs  3.60±1.58

P0.05

respectively)

but that at 8 weeks after operation was statistically different (6.60±1.07  vs  8.60±2.17

P0.05). The expression level of the VEGF in the experimental group at 8 weeks after operation was higher than that at 4 weeks and 12 weeks after operation (P0.05). Compared with the control group

the amount of CD34-positive microvessel in the experimental group at 4 weeks after operation was statistically different (5.30±1.83 per vision field  vs  7.30±1.34 per vision field

P0.05

but that at 8 and 12 weeks after operation was not (13.30±1.95 per vision field  vs  13.80±2.62 per vision field

P0.05; 10.90±2.28 per vision field  vs  11.80±1.22 per vision field

P0.05

respectively). The amount of CD34-positive microvessel in the experimental group at 8 weeks after operation was higher than that at 4 weeks and 12 weeks after operation (P0.05).        Conclusion       Allograft bone segment completes revascularization within 2 months after implantation into spatium intermusculare containing famous blood supply

showing no significant difference with autologous bone. It shows the feasibility of ectopic revascularization about allograft segment.