超高分子量聚DL-乳酸生物相容性和降解性的实验研究

目的:了解超高分子量聚DL-乳酸(PDLLA)的生物降解性和生物相容性。方法:将PDLLA植入到SD大鼠体内,在术后1年内,观察其活体情况、大体解剖学形态、组织病理学变化和血液学指标的改变。结果:PDLLA植入到 SD大鼠体内后,在术后6月左右基本降解,术后1年完全降解;在观察期内,其组织愈合、内脏解剖、局部光镜观察和血液学指标等均未见异常。结论:PDLLA在动物体内能顺利降解,不引起不良作用,具有较好的生物降解性和生物相容性。

Experimental Research on Degradation and Biocompatibility of Super-high-molecular-weight Poly-DL-lactic Acid

OBJECTIVE: The super-high-molecular-weight poly-DL-lactic acid (PDLLA), with the molecular weight of 900 kD, is a newly emerging biomaterial and potentially used in the therapy of bone fracture because of its excellent mechanical property. However the biocompatibility of this material has not been reported so far, therefore this experiment was designed to examine whether the super-high-molecular-weight PDLLA was harmful to creatures, when it was implanted in the body of animals for a long period. METHODS: The material was prepared in small cuboids, with the size of 1.0 mm x 1.5 mm x 2.0 mm, and these blocks were implanted into the masseteric space of SD rats and, the activity of the SD-rats was monitored continuously. The animals were sacrificed in the 3rd, 6th, 9th, 12th months after the operation and, the specimens were taken out from the animals. The examination included anatomical, pathological and haematological methods. The data were analyzed with SPSS 8.0. RESULTS: The wound healed well after the operation. Super-high-molecular-weight PDLLA degraded 6 months after the implantation. In the 3rd month after the operation, a thin fiber membrane around the materials was formed. In the 6th month, the membrane was much thinner than that in the 3rd month and completely disappeared in the 9th month. The pathological examination showed that slightly inflammatory reaction appeared in the tissue around these blocks in the 3rd month, but the inflammatory reactions were gradually remitted in the following 6th, 9th and 12th months. Further, the haematological examination did not show any abnormity during the 12-month observation period. CONCLUSION: The super-high-molecular-weight PDLLA can be degrade when it is implanted into the body of creatures, which proves its good biocompatibility.