| A large amount of patients with bone defect can be meet in the hospital, especially in the Department of Oral and Maxillofacial Surgery, these patients with deformed face often have bad social activity and lower life quality. So hospitals need a great deal of bone graft. Autograft and allograft bone have some shortcoming, thereby searching for ideal bone graft is a important task. With the development of the tissue engineering, artificial bones are successfully made in laboratory. Scaffold materials are very important in this techniques. The porous p-tricalcium phosphate scaffold has osteoconductivity and absorbability, it can be used as a scaffold material in the tissue engineering bone. The objective of this thesis is to reconstruct the segmental bone defect in dog mandibular, and to establish a laboratory foundation for the porous β-tricalcium phosphate scaffold be used in clinical hospital. 1. Experiment 1: The effects of the porous β -tricalcium phosphate ceramic on proliferation and differentiation of bone marrow stromal cells cellsObjective By means of colorimetric assay and Alkaline phosphatase (ALP) kit, To evaluate the effects of the porous β-tricalcium phosphate ceramic on proliferation and differentiationof bone mesenchymal stem cells.Methods: 500ul of 2×10~5/ml of BMSCs were implanted on every sample,at 1d. 3d, 5d, 7d and 9d, measured the proliferation and differentiation results of BMSCs. Result: The shape of BMSCs on the surface of the porous P-tricalcium phosphate ceramic was normal. About the proliferation, the experment group and the control almost had not significant difference, on the differentiation, only at 5d, 7d, 9d the experment group had a lower differentiation . Conclusion:Being on the surface of p-tricalcium phosphate ceramic, BMSCs can proliferate norally,and also have a higher Alkaline phosphatase activity.2. Experiment 2 Ectopic osteogenesis of the porous β -tricalcium phosphate ceramic loaded with bone marrow stromal cellsObjective: 1. To observe the osteogenesis of the porous P-tricalcium phosphate ceramic loaded with bone marrow stromal cells in a nude mice model.2.To look for a suitable method of loading BMSCs in p-TCP. Methods: BMSCs were obtained by harvesting the cancellous bone from the iliac crest of a rabbit. Then the BMSCs were isolated , expanded and induced in vitro, and obtained membrane-like seeds, wraped up the porous β-TCP with the membrane-like seeds, The β-TCP/BMSCs composites were implanted subcutaneously into the backs of nude mice. To observe the porous β-TCP osteogenetic activity. Results: At 8 weeks after implantation, A large amount of immature bone which composed mainly by cartilaginous bone formed in the surface and pores of the ceramics. Conclusion: The porous β-TCP has the ability of loading the osteogenetic factor, and it permits the tissue engineering bone infiltrating in the porous scaffold. This study suggested that theporous β-TCP could be used as a bone tissue engineering scaffold.3. Experiment 3 Experimental study of the porous β-TCP ceramic used as a bone tissue engineering scaffold for the repair of the critical calvarial defects in rabbitsObjective: Placing the β-TCP/BMSCs composites into the critical calvarial defects in rabbits,to observe the osteogenesis of the porous β-TCP ceramic as a bone tissue engineering scaffold in a calvarial defect model. Method: BMSCs were obtained by harvesting the cancellous bone from the iliac crest of a rabbit. Then the BMSCs were isolated , expanded and induced in vitro, about 20 days later, obtained membrane-like seeds, coated the porous β-TCP with the membrane-like seeds, The β-TCP/BMSCs composites were implanted into the calvarial defects of rabbits. At 8w and 12w, by the method of histomorphology, to observe the osteogenetic activity of the porous β-TCP/BMSCs composites in a calvarial defect. Results: At 12w after implantation, through the observation of X ray, a great deal of tissue engineering bone can be found,and also observed the degradability of the scaffold material. And through the microscope can find sheets of new bone filling the calvarial defects of rabbits. Conclusion : The β-TCP/BMSCs composites implanted into the critical calvarial defects in rabbits have a good ability of osteogenesis.4. Experiment 4 A study of a porous β-tricalcium phosphate ceramic used as a tissue engineering bone caffold material to reconstruct the segmental bone defect in dog mandibular. Objective:Through the technique of the tissue engineering,placing the β-TCP/BMSCs composites into the three-centimeter long segmental bone defect in dog mandibular. To observe the osteogenic ability of the porous β-TCP as a bone tissue engineering scaffold in large bone defect in loadingbone of big animals, and to search a suitable method of fixing scaffold material, and to supply a laboratory foundation for the porous β-tricalcium phosphate scaffold be used in clinical hospital. Method: processing the porous β-TCP to a block of 3.0 cm×2.0 cm× 1.0cm, BMSCs were obtained by harvesting the cancellous bone from the iliac crest of a dog. Then the BMSCs were isolated , expanded and induced in vitro, about 20 days later, obtained membrane-like seeds, coated the porous β-TCP with the membrane-like seeds, The β-TCP/BMSCs composites were implanted into the three-centimeter long segmental bone defect in dog mandibular. Results: At 6 month after operation, through the observation of X ray, can found that the defect area be reconstructed by tissue engineering bone, the dog mandibular had a good continuous contour. And by the microscope can find mature new bone filling the defect area, there were no sofe tissue between the tissue engineering bone and the dog mandibular bone. By the method of immunohistochemistric stain, can verify that the tissue engineering bone came from BMSCs of dog. Fixing the scaffold, rehabilitation of the bite relation,maintenance the continuous contour,with the titanium reconstructive plate and titanium network were practicable. Conclusion: The porous β-TCP/BMSCs composites helped with titanium reconstructive plate and titanium network can reconstruct the segmental bone defect in dog mandibular. It is a important laboratory foundation for the porous P-tricalcium phosphate scaffold be used in clinical hospital. 5. Experiment 5 A determinations and analysis of biomechanics of the porous P-tricalcium phosphate scaffold and its tissue engineering bone.Objective: Determinating the bending strengch and compressive strength of the porous β-tricalcium phosphate scaffold, and compared with those of bovine cancellous bone; Determinating the bending strengch and compressive strength of the tissue... |
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