Development of Biodegradable Materials for Tissue Reconstruction

探讨PLLA无纺布作为可降解支架材料短期植入的可能性。将细胞-支架复合物植入家兔体内，并试图确定影响细胞活力的因素。在体外，许多肝细胞以中间细胞的形态粘附在PLLA表面。然而，在这种基质上维持细胞功能是非常困难的。另一方面，体内研究表明，肝细胞和生物可降解聚合物的复合材料是有前途的肝重建的支架，如果肝细胞提供足够的营养和氧气。在同种异体移植的情况下，免疫抑制剂是生存所必需的，以避免免疫排斥反应。软骨细胞-PLLA复合物被用于尝试再生软骨。大鼠软骨细胞显示出良好的增殖粘附聚合物基板，如PLLA和II型胶原蛋白的生产在体外条件下。培养10 d后胶原蛋白产量达到最大。体内实验结果显示，bFGF包被于PLLA支架上后，软骨细胞在支架上分散分布，基质周围可见大量细小血管。当软骨细胞-PLLA复合物被移植到裸鼠中时，即使在同种异体移植中也不需要注射免疫抑制剂。在所有植入的复合材料周围观察到薄层纤维囊，宿主对植入物的炎症反应轻微。从硫堇清晰的组织学染色来看，很明显植入的细胞表现出它们的表型并形成新的成熟软骨。

The possibility of PLLA non-woven fabrics as the biodegradable scaffold for short-term implantation was explored. The cell-scaffold composite was implanted into rabbit and the factors governing the cell viability were attempted to be identified. Many hepatocytes adhered in vitro on the PLLA surface with the intermediate cell shape. However, the maintenance of cell fuction was very difficult on this substrate. On the other hand, in vivo studies revealed that the composites of hepatocytes and biodegradable polymers were promising as the scaffold for liver reconstruction, if hepatocytes were supplied with sufficient nutrients and oxygen. In the case of an allograft, an immunosuppressive agent was necessary for survival to avoid the immunorejection of recipient.A chondrocyte-PLLA composite was employed in an attempt to regenerate cartilage. Rat chondrocyte showed good proliferation on adherent polymer substrates like PLLA and type II collagen production under the in vitro condition. The collagen production became maximal on the 10th day after cultivation. From the in vivo study, seeded chondrocytes spread throughout the scaffold dispersively and a lot of small blood vessels were observed around the matrix when bFGF was coated on the PLLA scaffold. When the chondrocyte-PLLA composite was transplanted into nude mice, injection of an immunosuppressive agent was not necessary even in an allograft implantation. A thin layr fibrous capsule was observed surrounding all of the implanted composites, and the inflammatory response of the host to the implants was mild. From the clear histological staining with thionin, it was obvious that the implanted cells exhibited their phenotype and formed new matured cartilage.