The Experimental Study On In Vivo Bone Bioreactor

Objective: To engineer neobone by in vivo bone bioreactor, for autologous]y repairing bone defects. Methods: We developed 3 injectable and degradable gluey scaffolds rich in calcium, with sodium or chitosan as the main ingredient. Deliberate creation and manipulation of an artificial space between cortical bone and periosteum were made in tibia or cranium in NewZealand rabbits or dogs by jnjecting the gluey scaffold, which aroused pluripotent cells and growth factors leading to osteogenesis, without the need for cell transplantation and growth factor administration. We testified quality and quantity of the neobone at different levels such as molecular biology, histology, cytology, biomechanics, and imageology, the mechanism of which was preliminary explored. The newly formed bone in tibia was then harvested 8 weeks later and transplanted into its contralateral tibia defect. Results: After subperiosteal injection, histological osteogenic markers, such as osteocalcin and collagenâ… , were found positive in neobones. The newly formed bone could clearly be seen in CT and X-ray 8 weeks after injection. Eight weeks after transplantation, complete integration could he seen in the recipient site, with no apparent morbidity at the donor site. Cartilagous markers such as GAGs and collagenâ…¡were also positive after gluey scaffold injection. Conclusions: The injectable and degradable gluey scaffolds rich in calcium showed good histoeompatibility, and were easy in molding. Osteogenesis induced was feasible in the in vivo bone bioreactor, both tibia and cranium. Such newly formed bone showed great potentials in defect repairing.