Repair of massive bone defect by bone morphogenetic protein

1.采用胍抽提、丙酮分级、离子交换层析、凝胶过滤和高效液相色谱等方法从Dunn骨肉瘤（800 g）和人骨肉瘤裸鼠（800 g）中纯化骨形态发生蛋白.对各种胶原、羟基磷灰石和生物聚合物的免疫原性、生物相容性和生物降解性进行了测试，为BMP在体内的应用选择合适的载体.将BMP与各载体复合物植入小鼠背部肌肉内，术后3周进行放射学和组织学检查.胃蛋白酶消化的牛皮胶原、羟基磷灰石、聚乳酸、聚乳酸-聚乙二醇嵌段共聚物被证明是BMP的合适载体。将骨形态发生蛋白（BMP）与各种载体材料（胶原、聚乳酸、聚乳酸-聚乙二醇）复合植入兔胫骨骨膜下。BMP/聚乳酸-聚乙二醇复合材料4周时有新骨形成.在兔胫骨造成2cm骨缺损，将BMP/聚乳酸-聚乙二醇复合物与羟基磷灰石棒植入骨缺损处的差距。6周时在羟基磷灰石棒表面观察到新骨形成，12周时获得骨桥。我们将BMP与各种载体物质（胶原、聚乳酸、聚乳酸-聚乙二醇）的复合物（含和不含羟基磷灰石）植入猴背部肌肉中。只有BMP/胶原/羟基磷灰石在4周时诱导新骨形成。将BMP/胶原/羟基磷灰石复合物植入猴胫骨骨膜下。4周时观察到新骨形成。

1. Bone morphogenetic proteins were purified from Dunn osteosarcomas (800g) and human osteosarcomas in nude mice (800g) by guanidine extraction, acetone fractionation, ion-exchange chromatography, gel filtration and HPLC.2. We tested immunogenicity biocompatibility and biodegrability of various collagens, hydroxyapatites, and biopolymers, in order to select suitable carriers for BMP in vivo.3. We implanted the composites of BMP and each carrier substance into the back muscles of mice and examined new bone formation radiologically and histologically at 3 weeks.4. Pepsin-digested bovine skin collagen, hydroxyapatite, polylactic acid, and polylactic acid-polyethelene glycol, block copolymer proved to be suitable carriers for BMP.5. We implanted the composites of BMP and each carrier substance (collagen, polylactic acid, polylactic acid-polyethelene glycol) beneath the periosteum of rabbit tibia. New bone formation was observed by a composite of BMP/polylactic acid-polyethelene glycol at 4 weeks.6. We made a bony defect (2cm) in the rabbit tibia and implanted a composite of BMP/polylactic acid-polyethelene glycol in combination with hydroxyapatite rod into the gap of tibia. New bone formation was observed at the surface of the hydroxyapatite rod at 6 weeks and a bony bridge was obtained at 12 weeks.7. We implanted the composites of BMP and each carrier substance (collagen, polylactic acid, polylactic acid-polyethelene glycol) with and without hydroxyapatite into the back muscles of monkeys. Only BMP/collagen/hydroxyapatite induced new bone formation at 4 weeks.8. We implanted the composite of BMP/collagen/hydroxyapatite beneath the periosteum of monkey tibia. New bone formation was was observed at 4 weeks.