| ObjectiveTreatment of bone defect is a challenge in orthopaedics surgery. The best method up to date is autogenous bone transplantation. But because of donor bone shortage, donor area dysfunction, and the suffering of the patient in operation, its clinical application is constrained. Therefore, it's of great importance to seek efficient substitute of autogenous bone. In this experiment, the composite of a new kind of bioactive glass and vascular endothelial growth factor(VEGF) was transplanted to the New Zealand rabbits'radius defect, and see if it could provide a new solution to the bone defect treatment.MethodThe bioactive glass artificial bone, 360 mg(20 mg×18), was dipped into 50 mL (50 g/L) fibrinogen liquor, and blood vessel growth factor liquor (using double distilled water to dilute to 50μg/L) , was added for 30 minutes. Then it was moved to vacuum aspirator for 30 minutes until the blood vessel growth factor and the fibrinogen adhered fully on the wall of the vacuum aspirator. Two hundred and fifty U/mL prothrombin liquor with the same volume was added for 30 minutes. It was srerilized with ethylene oxide(EO) after natural air-dry, and reserved with temperature as low as -20°C for later use.Thirty six New Zealand rabbits (72 side radius), regardless of sexes, with weights varying from 2.5kg to 3kg were used for the experiment. After enethelization, the bilaterae radius was exposed. A bone defect area with length of 1.0cm was made. Then, BG/VEGF transplantation as the group A, BG transplantation as the group B, autogenous bone transplantation as the group C, and no transplantation as blank group D. After 4, 8, 12 weeks X-ray investigation, histologic examination, bone density measurement and biomechanical testing were made to compare the results. Results1. Anatomic Observation: 4,8,12 weeks after operation, new callus in the defect area of group A was more evident than that in group B, but almost the same to group C, and new born bone tissue could be observed. In group B, on both ends of the defect bones new callus was found. 12 weeks after operation, new bone formation replaced the composit, and bone repair was completed, there was still a little unabsorbed bioactive glass in group B, In group D, scattered new callus could be observed, and there are hyperplasia of fiber tissue.2. X-ray Investigation: 4,8,12 weeks after operation, new callus in group A and group C are significantly more evident than that in group B and group D. Twelve weeks later, the bone defect was healed in group A and group C, the medullary cavity was opened again. The bone defect in group B was closed up. Only scattered new callus of group D could be observed.3. Histologic Investigation: Bone cells of group A was quite active, lots of osteoblast could be observed. The amount of new bones in group A and group C was more obvious than that in group B, 4,8,12 weeks after operation. Histologic assessment suggests that bone healing in group A was superior than that in group B. Statistical analysis showed that there was no significant difference between group A and group C(P>0.05), but group A and group B are significantly different (P<0.01).4. The Bone Density Measurement: Bone density in group A and the group B in the same time had significant difference(P<0.01), while that in group B and group C had significant differences(P<0.01) at 4 weeks,8 weeks and 12 weeks after operation. But between group A and group C, there was no significant difference(P>0.05).5. Biomechanical Testing: The maximum bending load in the A group were significantly higher than that in the group B (P<0.05). Group C was superior to group B (P<0.01). whereas there was no significant difference between group A and group C (P>0.05).Conclusions1. Bioactive glass and VEGF complex bone behaved very well at osteoconduction and osteoinduction, and its effect to bone defect was significantly better than pure bioactive glass, and was almost the same to autogenous bone, and thus could serve as a new method for treatment of bone defect.2. Pure bioactive glass behaved well at osteoconduction, and had some effect for treating bone defect. But it had a big difference with autogenous bone. The blank group could do nothing on treating the bone defect.3. VEGF accelerated the bioactive glass to become vascularization, promoted the growth of chondrocyte and osteocyte, and thus hastened the repairment of defect bones. |
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