基于三维打印Sr-CaS/NBD多肽缓释微球支架材料修复感染性骨缺损的实验研究

Repairment for infective bone defect (IBD) is always the challenge clinically, and bone tissue engineering have been payed more attention in such area recently. In the previous study, we have proved that Sr-CaS has accelerated bone healing in repairment for bone defect. Moreover, inflammation inhibits osteoblast differentiation, NBD peptide as an agonist was able to effectively antagonize the inhibition of osteoblast differentiation through down-regulating NF-κB pathway. Based on that IBD has a long course and insufficient osteogenic activity, and local application of NBD peptide is inefficiency in continuous anti-inflammatory, we will design NBD peptide sustained-release microspheres, structure personalized scaffold material of Sr-CaS/ NBD peptide according with bone defect shape relied on Three-Dimensional Printing (3DP) at low temperatures in this project. We will investigate materials characterization, drug sustained-release characteristic, biomechanics, anti-inflammatory and osteogenic capacity of scaffold, according to FTIR, XRD, Micro-CT, histology, biomechanics and molecular biology. The study will integrate sustained-release microspheres and 3DP technology, achieve high volume load, slow release and activity maintenance of NBD peptide, take advantage of osteogenic capacity of Sr-CaS. It will provide scientific evidence for individual-based treatment of IBD with both lasting anti-inflammatory and bone defect repairment.

感染性骨缺损修复一直是临床医生面临的难题，采用骨组织工程方法修复倍受关注。课题组前期研究发现：Sr-CaS有促进骨缺损修复的优势；NBD多肽可防治炎症对成骨细胞分化的抑制且与其阻断NF-КB信号通路有关。针对感染性骨缺损病程较长，成骨活性不足，NBD多肽局部用药效率低下、难以持续抗炎问题，本研究拟合成NBD多肽载药缓释微球，采用三维打印技术将Sr-CaS与NBD多肽载药缓释微球混合，低温制备符合骨缺损形状个性化支架材料。采用FTIR、XRD、Micro-CT、生物力学和分子生物学等手段观察材料表征、药物缓释特性、异位抗炎成骨及生物力学特点。该研究将微球缓释技术与三维打印技术相结合，实现药物高量装载和缓慢释放，保持药物活性同时利用Sr-CaS优良生物活性提高复合支架促新骨再生能力，为感染性骨缺损个性化治疗，维持病灶局部长效抗炎同时实现骨质缺损修复提供新的思路。

背景：感染性骨缺损由于骨质感染加之合并骨缺损，其病情复杂、病程漫长，临床上具有感染复发率高，难以治愈特点，往往给患者带来沉重的经济负担，大大降低了患者的生活质量，也一直是骨科医师面临的最具挑战性的难题之一。临床迫切需要一种既能控制感染又能促进骨愈合的材料，基于此，我们尝试通过三维打印技术将载体材料(Sr-CaS)和NBD多肽载药缓释微球组装，制备成符合患者骨缺损病灶形状的个性化药物控释型载药支架材料进行填充治疗。.研究内容和结果：我们利用复乳-溶剂挥发法（W/O/W）制备Sr-CaS/NBD多肽缓释微球，对其生物相容性进行了评价，结果显示其生物相容性良好。采用C2C12细胞，通过TNF-α处理造成炎症刺激细胞模型。造模成功后，通过分组设计，比较NBD多肽，NBD多肽缓释微球和Sr-CaS/NBD多肽缓释微球支架对成骨细胞增殖、分化、矿化的影响及Sr-CaS/NBD多肽缓释微球支架复合共培养的抗炎效果，结果显示Sr-CaS/NBD多肽缓释微球具有抗炎、促进成骨细胞增殖、分化及矿化的作用。最后，建立大鼠胫骨感染性骨缺损模型，将Sr-CaS/NBD多肽缓释微球利用3D打印成所需的形状，采用影像学、骨形态计量学及Micro-CT三维结构等技术，研究Sr-CaS/NBD多肽缓释微球支架对大鼠胫骨感染性骨缺损模型骨破坏的影响，结果显示Sr-CaS/NBD多肽缓释微球支架具有抗感染、促进骨修复的作用。.结论：Sr-CaS/NBD多肽缓释微球支架制备成功，生物相容性良好，在细胞水平及动物体内实验中均表现出具有抗感染、促进骨修复的作用。