Abstract:

Objective:The super-high-molecular-weightpoly-DL-lactic acid (PDLLA), with the molecularweightof 900 kD, is a newly emerging biomaterial and potentially used in the therapy of bone fracture because of its excellentmechanical property. However the biocompatibility of this material has notbeen reported so far, therefore this experimentwas designed to examine whether the super- high-molecular-weight PDLLAwas harmful to creatures, when itwas 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@1.5 mm@2.0 mm, and these blockswere 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 datawere analyzedwith SPSS 8.0.Results:The wound healedwell af- ter the operation. Super-high-molecular-weightPDLLAdegraded 6 months after the implantation. In the 3rd month after the opera- tion, a thin fiber membrane around the materialswas 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, butthe inflammatory reactionswere 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.

Key words: super-high-molecular-weightpoly-DL-lacticacid, toxicity, SD-rat, biocompatibility, degrade