高压合成HA/PLGA骨折内固定材料的体内外降解研究

The study on the biodegradation mechanism of the HA/PLGA composite made by high-pressure for internal fixation of bone fractures

目的通过体内、外降解实验来探索超高压技术合成的HA/PLGA生物骨折内固定材料的降解规律。方法将HA/PLGA样品置于恒温SBF液中,定期测试失重率、平均分子量,并对试件作扫描电镜观察;同时将HA/PLGA样品置于新西兰白兔皮下、骨内,定期做光镜和电镜观察。结果HA/PLGA材料在体外的水解过程中,随着材料表面HA颗粒的脱落,水分子渐入材料内部,表现为早期平均分子量的降低,晚期失重率的升高。体内实验观测到材料逐渐被机体组织利用,并有血管等组织进入材料深部,形成对材料的持续性降解。结论高压合成的HA/PLGA在体内实验期间显示出良好的组织相容性,并具有生物降解特性,可被机体利用形成新生骨组织。

Objective To investigate the biodegradation mechanism of the HA/PLGA composite rods for internal fixation of bone fractures. Methods The HA/PLGA samples were immersed in the simulated body fluid （SBF） at 37℃. The average molecular weight and the ratio of the losing weight were measured periodically in vitro. In vivo study the samples of HA/PLGA were implanted subcutaneously and in the medullary cavities of News Zealand rabbits. The specimens were examined histologically by light microscope. The rod surfaces were examined using a scanning electron microscope. Results In the initial hydrolysis process of HA/PLGA, HA particles detached from the rod surface and water infiltrated into the rod. The average molecular weight dropped while the weight loss ration increased. In vivo observation showed that the biodegradable material was used by the body. New vessels grew into the samples to facilitate further degradation. Conclusion The HA/PLGA composite is biocompatible. It is also biodegradable and allows new bone formation.