Experimental Studies On Repairing Bone Defect With Tissue-engineered Bone Strengthened By Titanium Cage

About twenty years ago, with rapid development of life science and the engineering science, a new subject-tissue engineering, was put forward. It is an interdisciplinary field that applies the principles of engineering and the life science towards the development of biological substitutes that restore, maintain, or improve tissue function.The loss of bone was one of the most severe, most happened health problems that cost a lot Surgical reconstruction and mechanical devices confronted unsolvable difficulties or were imperfect solutions. Bone tissue engineering of autologous bone seems to be a promising method for repairing bone defects in clinical practice. In this study, bone marrow stromal cells(BMSC) were used as seed cells for bone tissue engineering. The biological characteristics of BMSC cultured in vitro were studied. The biological effects of recombinant human bone morphogenetic protein-2 (rhBMP-2 ) and dexamethasone(Dex) on BMSC were also investigated. To observe the condition of bone plerosis and the effect of titanium cage, using coral as scaffold strengthened by titanium mesh, the BMSC/coral-titanium composites were used to repair rabbit mandibular defects and femur defects.Method: BMSC obtained from rabbit marrow was cultured in vitro andinduced into bone marrow stromal osteoblast(MSO). During culture, the growth and the biological characteristic of BMSC were observed through cell morphological survey, cell growth curve, scanning electron microscope(SEM), alkaline phosphatase(ALP) stains, Von Kossa stains. The biological effects of rhBMP-2 and Dex on BMSC were measured with methylthiazol tetrazolium (MTT) method, ALP measurement kit and total cellular protein method. The effectiveness of new bone formation was evaluated by means of gross inspection, SEM observation, and histological examination.Result: BMSC can be cultured in vitro and induced into osteoblast. Under proper condition, rhBMP-2 and Dex can promote BMSC to the proliferate and differentiate into osteoblast In autogenenous mandibular and femur defects, the osteogenesis of BMSC/coral composite enforced by titanium mesh was obvious, and the new bone formation increased and became more mature in pace with time.Conclusion: Since BMSC can be induced into MSO and proliferate rapidly, it can be used as seed cells in bone tissue engineering, with little host morbidity. rhBMP-2 and Dex can promote the proliferation and differentiation of BMSC. The effectiveness of new bone formation of BMSC/coral composite enforced by titanium mesh is obvious in rabbit mandibular defect area, showing a promising prospect for clinical practice.