The dose-effect correlation between tissue engineered bone loaded BMP at different densities and new bone formation in vivo / 中华骨科杂志

ABSTRACT

Objective To investigate the effect of a kind of tissue engineered bone implants on healing of segmental bone defects. Methods A 15 mm bone defect experimental model at the right radius of New Zealand white rabbit was made. 24 animals of this model were divided into three groups at random. PLGA scaffords loaded with 5 mg BMP and about 1?106 BMSCs were implanted in Group 1(n=10); PLGA scaffords loaded with 2.5 mg BMP and about 1?106 BMSCs were implanted in Group 2(n=7); PLGA scaffords loaded with 1 mg BMP and about 1?106 BMSCs were implanted in Group 3(n=7). The osteogenesis at the defect area was observed by regular roentgenography and X-ray analysis, histological changes at the bone defects at 4th, 8th, 12th weeks after operation were studied and the new bone formation was measured by image analysis. Biomechanical analysis was done 12 weeks after operation. Results A large quantity of callus was found in all the 3 groups 4 weeks after repair. At the 12th week, the complete bone healing rate was 7/8, 3/5, 3/5, respectively in Group 1, 2 and 3. Group 1 had the largest quantity of new bone measured by histopathological study and X-ray analysis, and at the 12th week, the medullary cavity in this group became united. The compress stiffness, torsion stiffness and the maximal load in Group 1 were better than those in other groups. Conclusion The tissue engineered bone contructed by PLGA scaffords that are loaded with 5 mg BMP and BMSCs is capable of repairing segmental bone defects.