Matsushita Naofumi, Terai Hidetomi, Okada Takao, Nozaki Kazutoshi, Inoue Hikaru, Miyamoto Shimpei, Takaoka Kunio
Department of Orthopaedic Surgery, Osaka City University School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka, 545-8585, Japan.
J Orthop Sci. 2006 Oct;11(5):505-11. doi: 10.1007/s00776-006-1048-3.
Nothing has ever had osteoinductive capacity and degradability equivalent to that of autogenous bone, although many types of biomaterials have been developed. To address this issue, we constructed a new bone graft substitute with osteogenic potential and degradability by using porous beta-tricalcium phosphate (beta-TCP) granules, bone morphogenetic protein (BMP), and a synthetic block copolymer composed of poly-D: ,L: -lactic acid with randomly inserted p-dioxanone and polyethylene glycol (PLA-DX-PEG). In this experimental study, the bone-inducing capacity and degradation properties of the composite implant during the bone healing process were examined in vivo in a cortical and cancellous bone defect model in rabbits.
The advantages of this type of implant have been examined in a cortical bone defect model created in the distal femur of rabbits. The defects (6.5 x 5 mm) were filled with 30 mg of various implants: BMP-H [rhBMP-2, 0.0025% (w/w)], BMP-L [rhBMP-2, 0.000625% (w/w)], control A (beta-TCP alone), and control B (no implant). The distal femurs were harvested at scheduled intervals after surgery and examined for the evaluation of the bony repair of the defects by three-dimensional computed tomography and histology.
The repair of both cortical and cancellous bone occurred predominantly in the BMP-H group, and only minor cortical bone repair and cancellous bone formation were noted in the BMP-L and control A groups. Most of the beta-TCP was resorbed in the BMP-H group at 6 weeks after surgery, whereas a significant amount of beta-TCP remained in the BMP-L and control A groups.
beta-TCP granules coated with a BMP-retaining synthetic polymer appear to be effective in enhancing the repair of both cancellous and cortical bone defects. The early disappearance of the implanted beta-TCP and restoration of the normal anatomy of bone tissue are two notable features of this approach.
尽管已经开发出多种生物材料，但尚无任何材料具有与自体骨相当的骨诱导能力和可降解性。为解决这一问题，我们通过使用多孔β-磷酸三钙（β-TCP）颗粒、骨形态发生蛋白（BMP）以及由聚-D，L-乳酸与随机插入的对二氧环己酮和聚乙二醇组成的合成嵌段共聚物（PLA-DX-PEG）构建了一种具有成骨潜力和可降解性的新型骨移植替代物。在本实验研究中，在兔的皮质骨和松质骨缺损模型中对复合植入物在骨愈合过程中的骨诱导能力和降解特性进行了体内研究。
在兔股骨远端创建的皮质骨缺损模型中研究了这种类型植入物的优势。用30mg各种植入物填充缺损（6.5×5mm）：BMP-H [重组人骨形态发生蛋白-2，0.0025%（w/w）]、BMP-L [重组人骨形态发生蛋白-2，0.000625%（w/w）]、对照A（仅β-TCP）和对照B（无植入物）。术后按预定时间间隔采集股骨远端，通过三维计算机断层扫描和组织学检查评估缺损的骨修复情况。
皮质骨和松质骨的修复主要发生在BMP-H组，而在BMP-L组和对照A组仅观察到少量皮质骨修复和松质骨形成。术后6周时，BMP-H组中的大部分β-TCP被吸收，而BMP-L组和对照A组中仍残留大量β-TCP。
涂有保留BMP的合成聚合物的β-TCP颗粒似乎对增强松质骨和皮质骨缺损的修复有效。植入的β-TCP早期消失以及骨组织正常解剖结构的恢复是这种方法的两个显著特征。
