磺化类肝素多糖与骨形态发生蛋白的协同作用研究

项目名称： 磺化类肝素多糖与骨形态发生蛋白的协同作用研究

项目编号： No.50873034

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 轻工业、手工业

项目作者： 刘昌胜

作者单位： 华东理工大学

项目金额： 33万元

中文摘要： 骨形态发生蛋白（BMP）在骨组织修复过程中发挥重要的诱导成骨作用，但在体内环境中容易失活，而大剂量使用存在潜在的风险。本项目仿生体内生长因子糖基化过程，结合材料学和分子生物学的研究方法，制备了不同磺化位点和分子量的磺化壳聚糖，分别从细胞、基因及分子、动物层面上研究了磺化类肝素壳聚糖与骨形态发生蛋白-2的相互作用及其构效关系。本研究表明，6-O位磺化壳聚糖对促进BMP-2活性起到关键作用，而2-N位只起到辅助作用。低浓度的2-N，6-O磺化壳聚糖（26SCS）对BMP-2诱导的碱性磷酸酶活性、矿化形成以及成骨相关基因表达均有明显促进效果。增加链长和提高磺化度能够进一步提高其活性。在低浓度范围内，26SCS表现出比肝素更好的促进rhBMP-2能力。在此基础上，本项目制备了载rhBMP-2的磺化壳聚糖基纳米粒，通过对生长因子的保护和缓释放大其促进作用。动物实验结果表明，磺化壳聚糖作为BMP-2的协同因子在动物体内临界节段骨缺损修复中取得成功，不仅修复速度快，而且修复效果良好，甚至可达到自体骨水平。本项目研究表明，26SCS有促进BMP-2诱导成骨的作用，可以作为BMP-2的协同分子。

中文关键词： 类肝素；骨形态发生蛋白；多糖；骨修复；成骨活性

英文摘要： Bone morphogenetic protein (BMP) plays an important role of osteoinduction in bone repairing. However, it is accessible to degradation, which leads to lose of activity and the higher potential hazard existed if the dosage is increased. Therefore, in this project, the heparin-like sulfated chitosan with selected sulfated site, tunable Mw and sulfur content were synthesized mimicking the in vivo glycosylation process and integrating the methods of material science and biological molecules. The study indicated that 6-O sulfated chitosan played pivotal role in enhancing the osteoblast activities of BMP-2, while the role of 2-N sulfated was not evident. Low dose of 2-N,6-O sulfated chitosan (26SCS) could stimulate not only osteoblast differentiation induced by BMP-2, promote ALP activity and mineralization, but also upregulate the related gene expression. It appeared that low dose of 26SCS enhanced the interaction between BMP-2 ligands and receptors, as well as inhibited the function of Noggin, whereas BMP-2 signaling pathway was hampered when high dose of 26SCS was involved. In addition, the delivery system based on 26SCS has been developed to magnify the synchronous effect. Encouraging results have been obtained in repairing of the segmental critical-sized defects in rabbits. The biomechanics of regenerated bone can achieve the level of normal bone. These findings suggest that 26SCS is a more potent enhancer of BMP-2 and will be promising as a synergistic factor of BMP-2 for bone regeneration.

英文关键词： Heparin-like; Bone morphogenetic protein; Polysaccharide; Bone repairing; Osteogenetic activity