Calcium hydrogen phosphate dehydrate combined with gelatin and recombinant human bone morphologic protein 2/7 for repair of bone defects in rabbits / 中国组织工程研究

ABSTRACT

BACKGROUND: Studies have shown that the osteogenic ability of 10% strontium-doped calcium hydrogen phosphate dihydrate is higher than that of calcium hydrogen phosphate dihydrate and 5% strontium-doped calcium hydrogen phosphate dihydrate, but also found that the pore structure of 10% strontium-doped calcium hydrogenphosphate dihydrate is not ideal, and the early osteogenic effect is not satisfactory. OBJECTIVE: To investigate the osteogenic effect of the composite of 10% strontium-doped calcium hydrogenphosphate dehydrate and gelatin and recombinant human bone morphogenetic protein 2/7 (rhBMP2/7). METHODS: Gelatin-10% strontium-doped calcium hydrogenphosphate dihydrate and gelatin-10% strontium-doped calcium hydrogenphosphate dihydrate material containing 0.04 g/L and 1 g/L rhBMP2/7 were prepared respectively. Forty-five rabbit models of bilateral mandibular defects were prepared and then divided into five groups. In the blank control group, no material was implanted. 10% strontium-doped calcium hydrogen phosphate dihydrate (control group) and gelatin-10% strontium-doped calcium hydrogen phosphate dihydrate (gelatin group), 0.04 g/L rhBMP2/7-gelatin-10% strontium-doped calcium hydrogenphosphate dihydrate (0.04 g/L rhBMP2/7 group), and 1 g/L rhBMP2/7-gelatin-10% strontium-doped calcium hydrogenphosphate dihydrate (1 g/L rhBMP2/7 group) were implanted in the remaining four groups, respectively. Bone defect specimens were taken at 4, 8 and 12 weeks after surgery, and were examined by cone beam CT and immunohistochemistry. This study was approved by the Animal Ethics Committee of North China University of Science and Technology, China. RESULTS AND CONCLUSION: Cone beam CT examination revealed that at 8 weeks after surgery, bone repair was basically completed and the new bone tissue was almost fused with the surrounding tissue in the 1 g/L rhBMP2/7 group. Most of defect area was repaired, and the edge of new bone was unsmooth in the 0.04 g/L rhBMP2/7 and gelatin groups. Bone defect in the control group partially repaired. At 12 weeks after surgery, bone repair was completed in the gelatin, 0.04 rhBMP2/7 and 1 g/L rhBMP2/7 groups. Immunohistochemistry revealed that at 4 and 8 weeks after surgery, type I collagen expression in the 1 g/L rhBMP2/7 group was significantly higher than that in the other four groups (P 0.05). These results suggest that the addition of gelatin and 1 g/L rhBMP2/7 to 10% strontium-doped calcium hydrogenphosphate dihydrate can promote the repair of bone defects.