The Experimental Study Of Porous Titanium-niobium Alloy Composited With Bone Morphogenetic Protein

Object:The subject aims for using the new porous titanium-niobium alloy specimens as bone tissue regeneration project framework, to observe the characteristics shown in vitro and in vivo of porous titanium-niobium alloy specimen composited with bone morphogenetic protein. Then to provide further basis experimental evidence for the development of new porous prosthesis or bone implants for bone tissue regeneration.Methods:To develop titanium-niobium alloy specimens at70%porosity by ourselves. Then divide experimental groups into two group according to whether the titanium-niobium alloy specimens composited with bone morphogenetic protein (BMP):group A:pure porous titanium-niobium alloy experimental specimens; group B:porous titanium-niobium alloy experimental specimens composited with BMP. Experiment in vitro parts:mix porous titanium-niobium alloy specimens with BMSCS suspension according to experimental group. When observed attachment of BMSCs on alloy specimens,then move them to the appropriate medium. Using inverted phase contrast microscope, detection of osteoblasts Phenotype, scanning electron microscopy method, the alloy stent surface and holes within the BMSCs growth and osteogenic differentiation were observed and identified at different observation points. Experiment in vivo test parts:implant, experimental specimen of group A and B into rabbit thigh muscle,the tissue around the experimental specimen about0.5cm were taken at the time of10days,20days,30days,then the tissue were sliced into pieces to stained by HE. Then to observe the compatibility of the alloy and tissue, the condition of surrounding tissue growth and differentiation and the strength of tissue-metal interface.Using the SPSS17.0software package for statistical analysis, and measurement data were expressed as mean±standard deviation, each index of the group at the same time were compared by using analysis of variance between groups.Results:Findings In vitro experiments:through inverted phase contrast microscope, scanning electron microscopy and other methods, it is shown that the rabbit bone marrow mesenchymal stem cells show good quality of proliferating on the surface and into holes of specimens that without compositing with BMP. Also they shown a good biocompatibility and their phenotype of osteoblasts tested negative. While in the alloy specimens composited with BMP, rabbit bone marrow mesenchymal stem cells show shape conversion to osteoblasts, the osteoblast phenotype tested positive.Findings in the vivo test:at the time of10,20,30days after the implantation of the specimens into the thigh muscle of rabbits,HE staining of soft tissue section were tested from the muscle around0.5cm range of alloy stent in experimental tests.The tissue turned mild inflammatory reactions and foreign body reactions. While in the group composited with BMP, the formation of new blood vessels were found in the surrounding tissue through microscope at the time of10days, the formation of multiple neovascularization and partial visible hypertrophy, deep-dyed fiber cells were found microscope at the time of20days, calcium tissue were found through the microscope at the time of the30days after its implantation.Conclusion1. The rabbit bone marrow mesenchymal stem cells in vitro show good quality of adhesion and proliferation in the pure porous titanium-niobium alloy surface. The cells can grow into the porous titanium-niobium alloy specimens, but did not show osteogenic properties.2. The rabbit bone marrow mesenchymal stem cells in vitro can be induced to differentiation into osteoblasts via the composite of BMP and the porous titanium-niobium alloy specimens. The formation of calcium tissue also could be achieved in the spatial structure of the porous metal specimens.3. The rabbit muscle tissue showed mild inflammation and foreign body reaction toward porous titanium-niobium alloy specimens. Also the material itself could induce angiogenesis in the surrounding tissue, but they have little effect.4. The composite of BMP and porous titanium-niobium alloy implanted in rabbit muscle can promote the formation of fibrous tissue and early vascular ingrowth of fibrous tissue, fibrous tissue remodeling, and accelerate bone generation.