Expression of BMP-2, TGF-beta, bFGF in guided bone regeneration

OBJECTIVE: To study the mechanism of guided bone regeneration combined with osteoinduction by observation of expression of BMP-2, TGF-beta, bFGF. METHODS: 42 adult, male, New Zealand rabbits were randomly divided into 6 groups, each group being 7 rabbits. 10mm standard bone defect model was produced bilaterally in the middle radial shaft of each rabbit. Randomly, one defect enveloped with silicon membrane was tested, and the other served as control, sacrificed at 3 days, 1, 2, 3, 4, 5 weeks after surgery for histological observation, immunohistochemical staining of BMP-2, TGF-beta, bFGF and in situ hybridization of their cDNA probes. RESULTS: Histologically bone defects was sealed by silicon membrane, in which inflammation tissue and callus were formed from cells in bone ends. Similar expression of BMP-2, TGF-beta, bFGF between the test groups and control groups was noted. Inflammatory cells in the hematoma expressed bFGF and proliferating periosteal cells, endosteal cells, medullary mesenchymal cells expressed TGF-beta at 3 days postoperatively. Osteocytes in the bone ends and osteoblasts lining callus surface started to express BMP-2, TGF-beta at first week after surgery. Following the formation of inflammation tissue, in which giant cells, macrophages, mesenchymal cells expressed TGF-beta, bFGF respectively. Although the expression of three osteoinductors was the same between the test and control sides, their content was very different in both sides. The whole content in all test sides was much more than all control sides (P < 0.01), the content of test side was also much more than control side in each group. CONCLUSIONS: It is a key reason for successful guided bone regeneration that membrane tube formed a relatively independent bone regenerative situation to prevent around tissue from interruption, and to prevent osteoinductors from diffusion, so that enhanced osteoinductors induced bone regeneration to repair bone defects.