Development of Biodegradable Materials for Tissue Reconstruction

探讨了PLLA非织造布作为可生物降解支架用于短期植入的可能性。将细胞-支架复合材料植入兔体内，试图确定影响细胞活性的因素。多个肝细胞在体外附着于PLLA表面，呈中间细胞形态。然而，在这种底物上，细胞功能的维持非常困难。另一方面，体内研究表明，如果肝细胞提供足够的营养和氧气，肝细胞/可生物降解聚合物复合材料有望成为肝重建的支架材料。在同种异体移植的情况下，存活需要免疫抑制剂以避免受者的免疫排斥。软骨细胞-PLLA复合材料被用于尝试再生软骨。在体外培养条件下，大鼠软骨细胞在PLLA等贴壁聚合物基质上表现出良好的增殖能力，并产生II型胶原。培养后第10天，胶原产量最高。体内实验结果显示，当碱性成纤维细胞生长因子包被在PLLA支架上时，种植的软骨细胞分散分布在支架周围，周围可见大量的小血管。当软骨细胞-PLLA复合材料被移植到裸鼠体内时，即使在同种异体移植中也不需要注射免疫抑制剂。所有植入的复合材料周围都有一层薄薄的纤维包膜，宿主对种植体的炎症反应轻微。硫代巴比妥酸组织学染色结果显示，移植细胞有明显的表型，并形成了新的成熟软骨。

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.