Objective To investigate the ability of repairing bone defect with the compound of recombinant human insulinlike growth factor 1 (rhIGF-1), coralline hydroxyapatite(CHA) and autogeneous red bone marrow(ARBM), and to study the feasibility of the compounds being used as bone substitute materials. Methods Bilateral radius bone defects(11 mm in length) were created in 54 Chinese rabbits,which were randomly divided into 3 groups, and two different materials were randomly transplanted into the bilateral defects:in group 1, with material A(rhIGF-1/CHA/ARBM) and material B(CHA/ARBM); in group 2, with material C(rhIGF-1/CHA) and material D(CHA); in group 3, with E(autograft) and F(no implant) as controls. At 2, 4, 8 and 12 weeks, the effects were assessed by X-ray andimage analysis, biomechanics(at 12 weeks), as well as histological observation. Results X-ray and image analysis showed that material A of group 1was significantly superior to any other materials(P＜0.01). Antibending biomechanic detection showed that material A and Ewas significantly superior to the other materials(Plt;0.01), but no significant difference was found between A and E in the 12th week(Pgt;0.05). And by histological observation, in analogical bone morphological progress, materials C and D obviously inferior to materials A, B and E, but there was no significant difference between materials C and D. F had no evidence of new bone rebridging. Conclusion The recombinant compound CHA/ARBM(rhIGF-1),which posseses the potential ability of osteogenesis,osteoconduction and osteoinduction for bone defect repairing,can serve as a new type of autogenous bone substitute material.
OBJECTIVE: To investigate the ability of repairing bone defect with the compound of coralline hydroxyapatite porous (CHAP), fibrin sealant(FS) and staphylococcus aureus injection (SAI), and the feasibility to use the compounds as bone substitute material. METHODS: The animal model of bone defect was made on the bilateral radius of 54 New Zealand white rabbits, which were randomly divided into the experimental group(the defect was repaired with CHAP-FS-SAI), control group(with autograft) and blank control group(the defect was left unrepaired) with 18 rabbits in each group. The ability of bone defect repair was evaluated by gross observation, histopathological study, X-ray and biomechanical analysis 2, 4, 8 and 12 weeks after repair. RESULTS: (1) In the 2nd week, tight fibro-connection could be found between the implant and fracture site and there were many fibroblasts and capillary proliferation with many chondrocytes around CHAP in the experimental group, while only a few callus formed, and chondrocytes, osteoblast and osteoclast existed in the control group. (2) In experimental group and control group, a large quantity of callus was found 4 and 8 weeks; ossification of chondrocytes with weave bone formation were found 4 weeks and many osteocytes and weave bones and laminar bones were found 8 weeks. (3) In the 12th week, the complete ossification of implant with well bone remodeling, a large number of mature osteocytes and laminar were found in experimental group and control group, and CHAP still existed in the experimental group; the defect area filled with fibro-scar tissue and only many fibroblasts could be seen in blank control group. (4) X-ray findings were the following: In experimental and control groups, callus formation could be seen 2 weeks postoperatively, more callus formed 4 weeks, the bone defect area disappeared and CHAP scattered in the callus 8 weeks; the fracture line disappeared and medullary cavity became united (in control group); and in the 12th week, the cortex became continuous, the medullary cavity became united, and remodeling completed, while bone defect was not still united in blank control group. The maximal torque and torsional stiffness in the experimental group is higher than those in the control group 2 weeks (P lt; 0.05), but there was no significant difference (P gt; 0.05) between the two groups 4, 8, 12 weeks after repair. CONCLUSION: The compound of CHAP-FS-SAI has good biological compatibility, and it can be used for one kind of bone substitute material to repair the bone defect.
OBJECTIVE: To investigate the feasibility of coralline hydroxyapatite (CHA) as scaffolds in bone tissue engineering. METHODS: The bone marrow stromal cells from 4-month New Zealand rabbits were harvested and cultured in vitro. After multiplied, dexamethasone was used to promote the osteoblastic phenotype of the cells. The cells were harvested and then seeded into CHA. By means of tissue engineering technique, osteoblastic cells/CHA complex were formed. The complex were implanted subcutaneously in nude mice. The CHA alone was implanted as control. Bone regeneration was assessed 6, 8 weeks after implantation by histological and roentgenographic analysis. RESULTS: After six weeks of implantation, x-ray film showed high-density signal, osteoid tissue formed under histological examination. Large amount of new bone were formed and connected to trabecularism 8 weeks after implantation in the experimental group. While in the control group, there were no new bone formation, but amount of fiber tissue grew into the pore of CHA 8 weeks after implantation. CONCLUSION: CHA may be used as a good scaffold material for bone tissue engineering.
OBJECTIVE To improve the osteoinduction of coral and provide a perfect bone graft substitute for clinical bone defects. METHODS By combining coral with collagen and recombinant human bone morphogenetic protein-2(rhBMP-2), coral/collagen/rhBMP-2 composite was obtained. The composite was implanted into the back muscle pouches of mice, and coral/collagen or coral/rhBMP-2 were implanted as control. The osteoinduction of the composite was assessed by histology and image analysis system. RESULTS The chondrocyte differentiation and matrix formation were observed in local sites after one week, lamellar bone with bone marrow were formed after 4 weeks, and coral were absorbed partially. The quantity of osteoinduction was time-related and rhBMP-2 dose-related(P lt; 0.01). Coral/collagen and coral/rhBMP-2 implants did not show any bone or cartilage formation. CONCLUSION The coral/collagen/rhBMP-2 composite possesses a superior osteoinduction and will be a new type of bone substitute to be used in orthopedic and maxillofacial surgery.
In order to evaluate coral as a bone graft substitute in repair of bone defect, particulates of coral were implanted into skull bone defect of rabbit, 1.5 cm in diameter. Hydroxyapatite and blank were taken as controls. The rabbits were sacrificed at the second, fourth, eighth and twelveth weeks after the operation. The specimens were taken and performed histological examination and histomorphometry observation. Results were as follows: at the second week many multinucleus giant cells infiltrated. As time elapsed, the coral were progressively degenerated and new bone was formed to fill the defect. Up to the twelveth week, the coral degenerated completely and new bone formed in the center of the defect. Percentage of new bone was in defect was 36.9%. Compared with the controls, there were significant differences (P lt; 0.01). It was suggested that coral had good osteoconductility. Howevel, coral underwent rapid degeneration, it might result in inconplete repair of bone defect.