title: [Experimental research on degradation and biocompatibility of super-high-molecular-weight poly-DL-lactic acid].
abstract: 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.
  
  
  CONCLUSIONS
  The super-high-molecular-weight PDLLA can be degrade when it is implanted into the body of creatures, which proves its good biocompatibility.
authors.affiliation: West China College of Stomatology, Sichuan University.
authors.forename: Lei
authors.initials: L
authors.lastname: Liu
authors.forename: Qian
authors.initials: Q
authors.lastname: Zheng
authors.forename: Shicheng
authors.initials: S
authors.lastname: Wei
authors.forename: Zonglin
authors.initials: Z
authors.lastname: Zhao
authors.forename: Chengdong
authors.initials: C
authors.lastname: Xiong
authors.forename: Fucheng
authors.initials: F
authors.lastname: Luo
authors.forename: Xianmo
authors.initials: X
authors.lastname: Deng
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry / Q000378:metabolism*; D001673:Biodegradation, Environmental; D018786:Bone Substitutes; D020007:Implants, Experimental; D019344:Lactic Acid / Q000737:chemistry / Q000378:metabolism*; D008297:Male; D008334:Mandible / Q000378:metabolism / Q000601:surgery*; D008970:Molecular Weight; D011091:Polyesters; D011108:Polymers / Q000737:chemistry / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D001672:Biocompatible Materials; D018786:Bone Substitutes; D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C033616:poly(lactide)