Study Of RhBMP-2 In Combination With BFGF In Spine Fusion

In the present study we tried to find out the osteogenetic effect of rhBMP -2 in combination with bFGF on a FG carrier on rabbit transverse process fusion and their interaction to each other and tried to provide proof for the clinical application of rhBMP - 2 in combination with bFGF as a bone substitute.MethodsExperimental animals grouping: 30 Japanese big ear rabbits were distributed to three groups. One group was treated with FG + bFGF + rhBMP -2. The other two groups were treated with FG + rhBMP - 2 or FG separately as control groups.Tissue engineering materials construction; FG was gained by mixing fibrin-ogen, thrombin and CaCl₂ according to a certain method. bFGF and rhBMP -2 or rhBMP - 2 alone was mixed into FG for transplantation.Transplantation surgery: Expose the left transverse processes of the fifth and the sixth lumbar vertebrae. Rub out the posterior cortex of the transverse processes using a driller. Transplant the FG + bFGF + rhBMP - 2, FG + rhBMP - 2 or FG on to the exposed spongy bone separately.Evaluation of spinal fusion: The animals were killed and the lumbar vertebrae were anatomized out completely six weeks after transplantation surgery. The specimens were evaluated by direct observation, X - ray imaging, biomechanics and histology. The related data were analyzed by statistics.ResultsTransverse process fusion occurred in seven specimens in FG + bFGF + rh-BMP - 2 group, four in FG + rhBMP - 2 group and none in FG group. The DR images were analyzed with a special software to get the gray scale and acreage of the new bone. The gray scale, acreage and biomechanics data were compared (P < 0. 01). Significant osteogenesis happened in FG + bFGF + rhBMP - 2 group.DiscussionIn the present study, transverse process fusion had easy surgery procedures and small injury to the animals, so complications such as death, infection and paralysis were rarely seen. Tissue engineering bone should contain three basic elements; a. osteogenetic factors; b. the right carriers; c. mesenchymal cells. Bone morphogenetic protein (BMP) family is the most widely studied and applied factors. BMPs can induce mesenchymal stem cells to differentiate into os-teoblast and form new bone by cartilaginous osteogenesis. Recombinant human Bone morphogenetic protein - 2 is the only one osteogenetic factor for clinical application authorized by FDA. Many studies have shown bFGF is involved in normal bone healing and external bFGF can accelerate the process. The role of bFGF can be summarized as the follows: a. bFGF interacts intricately and widely with many growth factors. bFGF can promote TGF - β to move into bone marrow cells and stimulate TGF - β expression. bFGF can increase BMP mRNA expression, as is shown in vitro experiments. It is postulated bFGF can induce BMP production, b. bFGF can bind to surface receptors on osteoblast like cells and promote them to transform to osteoblast. bFGF also increase callus formation and the mine content in the callus. It can act on the adherence, proliferation and differentiation of bone marrow cells, c. bFGF can promote chondrocyte precursors to differentiate and mature into chondrocytes. It can also induce mesenchymal cells to differentiate into chondrocyte progenitors and accelerate cartilagi-...