超临界流体技术复合人工骨生物替代材料修复腔隙性骨缺损☆

背景：复合材料是目前骨组织工程研究的热点之一。通过两类材料的复合，取长补短，使之具有更好的骨传导功能。 目的：通过超临界流体技术将聚乳酸和同种异体骨粉合成复合型骨替代生物材料置入骨缺损模型，检测其成骨能力。 设计、时间及地点：观察性实验，于2005-12/2006-06在南方医科大学组织工程实验室和山西省医用组织库完成。 材料：20只家兔由南方医科大学动物实验中心提供。新鲜健康成人尸体股骨干标本由山西省医用组织库提供。聚乳酸粉末由山东医疗器械研究所提供。 方法：首先将同种异体皮质骨粉与聚乳酸在超临界二氧化碳作用下复合成多孔骨生物替代材料。将家兔左侧股骨远端造成1.5 cm×1.0 cm×0.6 cm大小的骨缺损，植入复合材料。 主要观察指标：于植入后2，4，8，12周取股骨远端植入材料区，进行大体观察、X射线检查、组织学检查和扫描电镜检查。 结果：实验第2周取材时大体观察已经接近皮质骨强度，第4周电镜观察见材料内部出现成骨细胞，第8周时X射线检查骨缺损基本已经被完全修复，第12周组织学观察材料内部软骨基质钙化，已经形成编织骨，且部分成骨小梁样结构。 结论：采用聚乳酸和同种异体骨粉制备出的复合材料生物相容性良好，修复骨缺损能力良好，可以做为骨组织替代材料。

Composite biomaterials for the repair of lacunar bone defects fabricated by supercritical fluid technique

BACKGROUND: Composite material is one of hot spots in the field of bone tissue engineering study. Compounding two kinds of materials may lead to a better bone conduction function. OBJECTIVE: To evaluate the osseointegration effect of the novel composite biomaterial fabricated by granulated allogeneic bone and polylactic acid using the supercritical fluid technique on the bone defect repair. DESIGN, TIME AND SETTING: An observational study was performed in the Tissue Engineering Laboratory of Southern Medical University and Shanxi Provincial Medical Tissue Bank from December 2005 to June 2006. MATERIALS: Twenty rabbits were offered by Animal Experimental Center of Southern Medical University. Fresh human corpse femoral shaft samples were purchased from Shanxi Provincial Medical Tissue Bank. Polylactic acid was a product of Shandong Medical Instrument Institute. METHODS: Granulated allogeneic bone and polylactic acid were compounded to fabricate the porous bone composite scaffold by the supercritical fluid technique. The composite scaffold was implanted into bone defect in right distal femur at a size of 1.5 cm× 1.0 cm×0.6 cm. MAIN OUTCOME MEASURES: At 2, 4, 8, 12 weeks after grafting, the biocompatibility and repairing effect were estimated by the technique of general and histological observations, X-ray film and scanning electron microscope examination. RESULTS: At 2 weeks, the harvested samples were close to the cortical bone with regard to the bone strength by general observation. At 4 weeks, scanning electron microscope results showed the appearance of osteoblasts in the materials. At 8 weeks, bone defects were almost repaired according to X-ray film. At 12 weeks, the cartilage matrix in materials had calcified and formed into woven bone, some of them were presented as bone trabecula-like shape. CONCLUSION: The composite biomaterial based on polylactic acid and allogeneic bone granulate using supercritical fluid technique could provide excellent biocompatibility and good repairing effect on bone defect. It could be applied as a substitute of bone tissue.