Repairing Bone Defects Of Rabbits' Radius With Nano-hydroxyapatite/collagen Materials Adding Vascular Endothelial Growth Factor (VEGF)

Objective: To investigate the treatment effect of bone defects of rabbits' radius, repairing by nano-hydroxyapatite/collagen materials (NHAC) and vascular endothelial growth factor (VEGF).To provide basic theories and experiments' criterions for further studies and clinical applications of the bone tissue engineering kickstand, and also provide new thinking of the treatment which repair bone defect and bone nonunion.Method: Thirty-six healthy rabbits were divided into three groups, twelve rabbits each. A group: blank control group, B group: NHAC control group and the C group is NHAC/VEGF experimental group. The rabbits' left radiuses were cut off 1 cm with periosteum in the middle 1/3 to make a standard model of bone defect. Cylinders, the diameter is 0.4cm and the height is 1cm, were made used with NHAC. And 150ng VEGF was added into the experimental group. The wounds of the rabbits in A group were sewed up directly without any treatment of the bone; the bone defects of the rabbits in B group were repaired with NHAC artificial bones and the C group with NHAC/VEGF artificial bones. After 2, 4 and 8 weeks, 4 rabbits in each group were killed to evaluate whether they have significant differences of bone healing according to general observation, X picture, pathological section and test bone density.Results: General observation: the gross observation showed that the differences of grading of artificial bone adhesion were not significant between control group and experimental groups in the same time. The experimental groups were faster in healing and better in quality than the other groups.X picture aspect: the X pictures show that the C group is better than the other two groups in osteotylus aspect and the repairing of bone defects aspect. And also the B group is better than the A group.Bone density aspect: The difference of bone density of every each two groups in the same time has significant difference (P<0.05). Both of the B group and the C group have significant differences (P<0.05) between 2 weeks,4 weeks and 8 weeks. But the A group has no significant difference (P>0.05).Histology aspect: Histology examination shows that the C group is better than the B group and the A group in the fibrous connective tissue,bone trabecula and osteoid tissue aspects. And also the B group is better than the A group. According to the score criteria of Lane-Sandhu, the three groups shows significant difference (P<0.05) between each two groups in the same time after operation.Conclusion:â‘ NHAC plays a good role of the bone conduction and the bone induction.â‘¡VEGF can promotes the growth of chondrocyte and osteocyte, and is benefit for the repairing of the bone defect and bone nonunion.â‘¢The artificial bone of NHAC composited with VEGF has a good function in osteoinduction, activing the growth of osteocyte, fasting the healing of the bone, and can be used as a new type of composite artificial bone to repair bone defect.