Abstract:

BACKGROUND: For its extensive sources and specific biological characteristics, heterogeneous deproteinized bone (DPB) as the tissue-engineered scaffold material gets a good application prospect in repair of large segmental bone defects.
OBJECTIVE: To prepare scaffold material by compositing modified heterogeneous DPB with recombinant human bone morphogenetic protein 2 (rhBMP2) and evaluate the osteogenic ability in repairing large segmental long bone defects in large-sized animals.
METHODS: Twenty-four goats were randomly and evenly divided into three groups: DPB, autologous bone, and DPB+ rhBMP2. Bone defects (20% in length) were made in the middle and lower segments of the right tibia of each goat, and according to group design, different bone grafts were implanted and fixed using semi-ring slot external fixer. At 4-24 weeks after surgery, X-ray examination was performed once every other 4 weeks. At 24 weeks after surgery, newly formed bones were taken out for determining the repair effects of bone defects through dual-energy X-ray analysis, histological observation, and biomechanical analysis.
RESULTS AND CONCLUSION: The prepared DPB exhibited a three-dimensional porous structure, with a porosity of (78.5±6.45)% and pore size of (472.5±7.02) μm. Time-dependent bone repair was found in each group. Results regarding anti-compression test, three-point anti-bend test, and anti-torsion test were greatest in the autologous bone group, followed by the DPB+ rhBMP2 group, and lastly the DPB group. There were no significant differences in tibial bone density, bone mineral content, anti-compression pressure and ultimate pressure, anti-bending load and ultimate load, anti-torsion torque and ultimate torque between autologous bone group, DPB+ rhBMP2 group and normal bone control group. These findings indicate that modified heterogeneous DPB composited with rhBMP2 has osteogenic ability equivalent to autologous bone in repairing large segmental long bone defects in goat tibias. Therefore, it can be applied as tissue-engineered scaffold material.