The development of degradable polymer scaffolds is a key issue in bone regeneration. Poly(D, L-lactide) (PDLLA) and its derivatives have usually been applied to the construction of degradable scaffolds, but these scaffolds had problems with acidic degradation products and quick loss of mechanic strength during the later degradation, which usually led to scaffold collapse and cavity formation because of the slower rate of bone regeneration. In the present paper, a polysaccharide derivative, agarose acetate (AGA), was synthesized and a novel porous AGA scaffold was successfully developed through a salt-leaching process. The AGA scaffold had over 90% porosity without swelling in water, and compared to collapse and acidic products of PDLLA scaffold during degradation, the AGA scaffold maintained a stable morphology and a nearly neutral pH value over 18 months' degradation in PBS. A bone mesenchymal stem cells (BMSCs) adhesion and proliferation experiment showed that more cells adhered to the AGA scaffold than to the PDLLA scaffold. A subcutaneous implant test showed that the AGA scaffold slowly degraded and did not cause an inflammatory response surrounding the implantation lesion site. AGA scaffold was implanted into femur defects in New Zealand white rabbits to test its in vivo performance. Results indicated that the AGA scaffold accelerated the process of bone regeneration compared to the PDLLA group and, with time, new bone was formed from the margin toward the center of the scaffolds, and the scaffold left in place retained its porous structure without collapsing. Meanwhile, the AGA scaffold showed a low degradation rate and kept its shape during the in vivo degradation compared to the PDLLA scaffold. This performance could have the benefit of integrated regenerative bone being formed instead of cavities due to the quickly degraded scaffold disappearing. These results demonstrate that the AGA scaffold has significant potential in bone regeneration applications.

中文翻译：

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醋酸琼脂糖与PDLLA支架修复兔股骨缺损的比较研究。

可降解聚合物支架的开发是骨再生中的关键问题。聚（D，L-丙交酯）（PDLLA）及其衍生物通常被用于可降解支架的构建，但是这些支架存在酸性降解产物和在后续降解过程中机械强度快速损失的问题，这通常导致支架骨再生速度较慢，因此会塌陷并形成空腔。本文合成了多糖衍生物醋酸琼脂糖（AGA），并通过盐浸工艺成功开发了新型多孔AGA支架。AGA支架的孔隙率超过90％，而在水中不会溶胀，并且与降解过程中PDLLA支架的坍塌和酸性产物相比，在PBS中降解18个月后，AGA支架保持了稳定的形态和接近中性的pH值。骨间充质干细胞（BMSCs）粘附和增殖实验表明，粘附到AGA支架上的细胞比粘附在PDLLA支架上的细胞更多。皮下植入物测试显示，AGA支架缓慢降解，并且不会引起植入病变部位周围的炎症反应。将AGA支架植入新西兰白兔的股骨缺损中，以测试其体内性能。结果表明，与PDLLA组相比，AGA支架加速了骨骼的再生过程，并且随着时间的流逝，新的骨骼从支架的边缘向中心形成，并且留在原位的支架保持了其多孔结构而不塌陷。与此同时，与PDLLA支架相比，AGA支架在体内降解过程中显示出较低的降解速率并保持其形状。由于快速降解的支架消失，这种性能可能具有形成整合的再生骨而不是蛀牙的好处。这些结果表明，AGA支架在骨再生应用中具有巨大潜力。