背景:骨形态发生蛋白2是目前研究最广泛与诱导成骨活性最强的骨形态发生蛋白之一, 但是单纯骨形态发生蛋白植入后会被组织液稀释及蛋白酶分解, 不能保持持久的药物浓度, 难以发挥有效的骨诱导作用.目的:实验以磷酸钙骨水泥/纤维蛋白胶复合材料作为骨形态发生蛋白2的载体, 观察其对骨质疏松性骨折的修复效果.方法:取54只雌性SD大鼠, 切除双侧卵巢制作骨质疏松模型, 3个月后制作股骨中段骨折模型, 随机分成3组, 每组18只, 克氏针内固定组骨折断端不注射任何材料;复合材料组骨折断端注射0.5m L磷酸钙骨水泥/纤维蛋白胶复合材料, 载生长因子复合材料组骨折断端注射0.5m L负载重组人骨形态发生蛋白2的磷酸钙骨水泥/纤维蛋白胶复合材料.骨折后4, 12周, 进行股骨骨折标本X射线检查、Micro-CT检测、生物力学三点弯曲实验及病理观察.结果与结论:①载生长因子复合材料组骨折愈合评分高于克氏针内固定组、复合材料组 (P <0.05) ;②载生长因子复合材料组骨折后4, 12周的骨体积分数、骨小梁厚度及骨小梁数量均高于克氏针内固定组、复合材料组 (P <0.05) , 骨小梁分离度均低于克氏针内固定组、复合材料组 (P <0.05) ;③载生长因子复合材料组骨折后4, 12周的最大载荷、刚度均高于克氏针内固定组、复合材料组 (P <0.05) , 骨折后4周的弹性模量高于克氏针内固定组、复合材料组 (P <0.05) ;④ 克氏针内固定组骨折后4周主要可见纤维软骨骨痂, 骨折后12周骨痂重塑为板状骨, 硬骨痂含量较少;复合材料组、载生长因子复合材料组骨折后4周可见明显的纤维性骨痂与软骨性骨痂, 载生长因子复合材料组硬骨痂含量较复合材料组多, 骨折后12周硬骨痂重塑为板状骨;⑤结果说明, 负载重组人骨形态发生蛋白2的磷酸钙骨水泥/纤维蛋白胶复合材料, 可促进骨质疏松性骨折的愈合, 提高骨强度.%BACKGROUND: Bone morphogenetic protein 2 is a most widely studied and osteogenic-inducing bone morphogenetic protein. However, simple bone morphogenetic protein can be diluted by tissue fluid and decomposed by protease after implantation, so it is difficult to maintain sustained drug concentration or play an effective role in bone induction. OBJECTIVE: To observe the effect of repairing osteoporotic fracture through calcium phosphate cement/fibrin glue composite as the carrier of bone morphogenetic protein 2. METHODS: Fifty-four female Sprague-Dawley rats were selected to remove bilateral ovaries for making osteoporosis models. Three months later, the middle femoral fracture models were made, and then randomized into three groups, with 18 rats in each group. Kirschner wire fixation group was injected nothing. The fracture end was injected with 0.5 mL calcium phosphate cement/fibrin glue (composite group) or calcium phosphate cement/fibrin glue loaded with recombinant human bone morphogenetic protein 2 (loaded group) . At 4 and 12 weeks after fracture, X-ray examination, micro-CT examination, biomechanical three-point bending test and pathological observation were performed. RESULTS AND CONCLUSION: (1) The fracture healing score in the loaded group was higher than that in the other two groups (P < 0.05) . (2) The bone volume fraction, trabecular thickness and number of trabeculae at 4 and 12 weeks in the loaded group were higher than those in the other two groups (P < 0.05) , and the trabecular segregation was lower than that in the other two groups (P < 0.05) . (3) The maximum load and stiffness at 4 and 12 weeks in the loaded group were higher than those in the other two groups (P < 0.05) , and the elastic modulus at 4 weeks after fracture was higher than that in the other two groups (P < 0.05) . (4) Fibrocartilage callus was mainly seen at 4 weeks after fracture in the Kirschner wire fixation group, and the callus was reconstructed into lamellar bone at 12 weeks after fracture with less callus content. Obvious fibrocartilage callus appeared at 4 weeks after fracture in the composite and loaded groups, and the callus was reconstituted into a plate-like bone at 12 weeks. (5) These results imply that the calcium phosphate cement/fibrin glue composite loaded with recombinant human bone morphogenetic protein 2 can promote the healing of osteoporotic fracture and improve bone strength.
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