The Application Of Growth Factor And Its Sustained Release System In Bone Tissue Engineering

Bone defect and deformity have been common diseases in clinical. And biological artificial bone fabricated by seed cells, scaffolds, and growth factors according to tissue engineering methods has been thought as one of the most effective technique which could potentially be used in the future for the treatment of large bone defects. Some experiments have been done on how to keep and lengthen biological activity of growth factor in this research. At first, experiments about the effects of rhBMP-2 and rhbFGF on proliferation and differentiation of cultured bone mesenchymal stem cells (BMSCs) were done so as to find an ideal using way of them to obtain a large quantity of seed cells. Then, the polybutylcyanoacrylate nanoparticles were fabricated to be carrier of rhBMP-2, and experiments about biological effects of such nanoparticles on cultured BMSCs were done in order to clarify the efficiency of the nanoparticles on sustained releasing rhBMP-2. At last, experiments on ectopia osteogenesis and repair of rabbit critical-sized cranial defect by tissue engineered bone fabricated by coral, BMSCs and sustainedly released rhBMP-2 by collagen were done. The efficiency of collagen on sustained releasing rhBMP-2, and the importance of collagen and BMSCs on enhancing treatment of bone defect have been verified finally.Chapter 1: Biological effects of rhBMP-2 and rhbFGF on cultured bone mesenchymal stem cellsExperiment 1: The effects of rhBMP-2 and rhbFGF on proliferation of bone mesenchymal stem cells[Abstract] Objective To evaluate the effects of rhBMP-2 and rhbFGF on proliferation of rabbit bone mesenchymal stem cells (BMSCs) by using them alone, associatedly and sequentially. Methods Cell culture technique and MTT colorimetric assay were used to evaluate the proliferation of BMSCs on the 1st, 3rd, 5th, 7th, and 10th day by adding rhBMP-2 and rhbFGF on different ways. Results Statistical analysis showed that both rhBMP-2 and rhbFGF could enhance the proliferation of BMSCs significantly in long term, and also in a dose-dependent manner. The effects of the two growth factors were significantly higher by using them associatedly than by using them alone or sequentially. Conclusion Different growth factor has different effect on proliferation of BMSCs by adding them on different ways.Experiment 2: The effects of rhBMP-2 and rhbFGF on differentiation of bone mesenchymal stem cells[Abstract] Objective To evaluate the effects of rhBMP-2 and rhbFGF on differentiation of rabbit BMSCs by using them alone, associatedly and sequentially. Methods Alkaline phosphatase (ALP) kit and Coomassie brilliant blue assay were used to evaluate ALP level and protein content of BMSCs so as to reflect differentiation of the cells on the 2nd, 5th, 7th, and 10th day by adding rhBMP-2 and rhbFGF on different ways. Results Statistical analysis showed that rhBMP-2 could enhance while rhbFGF could inhibit the differentiation of BMSCs significantly in long term, and also in a dose-dependent manner. The effects of using rhBMP-2 alone was similar tothat of using the two growth factors associatedly, and they were significantly higher than that of using rhbFGF alone and using them sequentially. Conclusion Different growth factor has different effect on differentiation of BMSCs by adding them on different ways.Chapter 2: Biological effects of the recombinant human bone morphogenetic-2 polybutylcyanoacrylate nanoparticles on cultured bone mesenchymal stem cellsExperiment 1: Fabrication and property evaluation of the recombinant human bone morphogenetic-2 polybutylcyanoacrylate nanoparticles. [Abstract] Objective To fabricate the recombinant human bone morphogenetic-2 polybutylcyanoacrylate nanoparticles, and to evaluate the property of the nanoparticles. Methods The rhBMP-2 nanoparticles were prepared by improved emulsion polymerization method according to orthogonal factorization optimization method. Many other methods were used to evaluate morphologic property, encapsulation rate, ectopia osteogenesis, drug release property, stability and...