消旋聚乳酸/羟基磷灰石复合材料成骨性的体内实验研究

In vivo study of bone formation of PDLLA/HA composite

目的探讨消旋聚乳酸/羟基磷灰石(PDLLA/HA)复合材料在动物体内的生物相容性和成骨性。方法将66只日本大耳兔随机为3组,每组22只。其中2组分别于股骨髁间植入PDLLA/HA复合材料圆柱棒(PDLLA/HA组)和PDLLA圆柱棒(PDLLA组),1组仅手术而不植入材料作为对照组。术后3、6周植入部位摄X线片观察植入材料的变化及其与周围组织的结合情况;术后3、6、12、24周每组各处死5只兔,进行植入部位大体解剖学观察和组织病理学观察。结果术后X线观察显示PDLLA/HA组植入材料显影良好,与周围组织有明显界限;而PDLLA组可以看到明显的孔道。大体解剖学和组织病理学观察显示PDLLA/HA组术后早期局部炎症反应明显轻于PDLLA组,材料与周围组织结合紧密,膜外有少许新骨生成;6周时膜外新骨增多;12周时复合螺钉周围有少量新生骨小梁形成,边缘附有大量的成骨细胞;24周时可见纤维组织长入材料,材料色、形、质与周围结缔组织相近。而PDLLA组材料降解明显,12周后已不能维持棒体形状。结论PDLLA/HA复合材料具有良好的生物相容性和体内成骨性。

Objective To investigate the biological compatibility and bone formation of PDLLA /HA composites in vivo. Methods A total of 66 Japanese rabbits were randomly divided into 3 groups, 22 rabbits in each. In 2 of the groups, rods made of PDLLA/HA composites (PDLLA/HA group) or PDLLA (PDLLA group) were transplanted into the condylar joints of the rabbits. The rabbits in another group received an operation without transplantation (control). The condylar joints were examined by X-ray at 3 and 6 weeks after the operation to observe the change of the transplanted materials and its integration with the adjacent tissues. The rabbits were killed at 3, 6, 12, and 24 weeks after the operation (3 for each time point in each group), the joints transplanted with the rods were observed macroanatomically and histopathologically. Results In the PDLLA/HA group, the transplanted rod with a clear margin was detected by X-ray after the operation, while in the PDLLA group holes could be obviously observed. Macroanatomical and histopathological examinations showed that the early local inflammatory reaction in the PDLLA/HA group was markedly milder than that in the PDLLA group. In the PDLLA/HA group, the transplanted rod was integrated with the adjacent tissues closely with a few new bones outside. At 6 weeks, the amount of the new bones increased. Bone trabecula formation around the rod with a large number of osteoblasts could be observed at 12 weeks. At 24 weeks, fiber tissues, which were similar to the surrounding connective tissues, could be seen in the rods. Whereas, in the PDLLA group, the transplanted rods were degraded, the shape of the rods could not be found at 12 weeks. Conclusion PDLLA/ HA material has a good biological compatibility and bone formation in vivo.