人发角蛋白复合聚乳酸棒的力学强度及体内降解

背景:生物可降解内固定材料已应用于临床,但目前仅用于非承重骨的内固定。研究一种具有较高的初始力学强度和早期降解速度缓慢,并能用于承重骨内固定的器材是临床所需要的。目的:对自行研究的人发角蛋白复合聚乳酸骨折内固定棒进行初始机械力学强度测试和动物体内降解观察。设计:重复测量设计。单位:南方医科大学珠江医院骨科中心,南方医科大学人体解剖学教研室。材料:实验于2002-09/2003-10在南方医科大学完成。选择54只成年SD大鼠。方法:①利用MTS-858MiniBionix型生物力学测试机分别对20根人发角蛋白复合聚乳酸棒的剪切强度、弯曲强度和弯曲模量进行测试,了解人发角蛋白复合聚乳酸骨科内固定棒的初始机械力学性能。②108个人发角蛋白复合聚乳酸试件随机植入54只SD大鼠双侧脊旁皮下组织中,分别于术后1,2,4,8,12,16,20,24,28周取出(每个时间点6只大鼠),测量重量损失,了解人发角蛋白复合聚乳酸在SD大鼠体内的降解情况。主要观察指标:①人发角蛋白复合聚乳酸骨折内固定棒的力学强度。②人发角蛋白复合聚乳酸骨折内固定棒动物体内降解情况。结果:54只大鼠均进入结果分析。①人发角蛋白复合聚乳酸骨折内固定棒具有良好的初始机械力学强度,其剪切强度为241MPa,弯曲强度为358MPa,弯曲模量为13GPa。②人发角蛋白复合聚乳酸在SD大鼠体内可以良好的降解,早期降解较慢,而晚期降解较快。结论:人发角蛋白复合聚乳酸骨科内固定棒具有良好的初始力学强度,且在体内可以良好的降解。

Mechanical strength and degradation in vivo of human hair polylactic acid composite rods

BACKGROUND: Biodegradable internal fixation devices have been used in clinics. However, they can only be used for internal fixation of non weight-bearing bones. A new kind of biodegradable internal fixation device with high initial strength and slow early degradation, which can be used for weight-bearing bones, is required.OBJECTIVE: To test the initial strength and observe the degradation of human hair polylactic acid (HHPLA) composite rods.DESIGN: Repeated measurement designSETTING: Center of Orthopaedic Department, Zhujiang Hospital, Southern Medical University; Department of Human Anatomy of Southern Medical UniversityMATERIALS: The experiment was conducted in the Southern Medical University between September 2002 and October 2003. Totally 54 adult SD rats were recruited.METHODS: ①The shear strength, the bending strength and the bending modulus of 20 HHPLA composite rods were tested with the biomechanical testing system (MTS-858 Mini Bionix) to investigate the initial nechanical feature of HHPLA composite rods. ②A total of 108 samples of HHPLA composite rods, which were developed for internal fixation of fracture, were randomly implanted in bilateral dorsal subcutaneous tissue of 54 SD rats and taken out at weeks 1, 2, 4, 8, 12, 16, 20, 24 and 28 (6 rats at each time point). The weight losses were measured to understand the degradation of HHPLA composite rods in SD rats.MAIN OUTCOME MEASURES: ①Mechanical strength of HHPLA composite rods. ②Degradation in vivo of HHPLA composite rods.RESULTS: Totally 54 rats entered the result analysis. ①HHPLA composite rods has good initial mechanical strength. Its shear strength of the HHPLA rod was 241 MPa, bending strength was 358 MPa, and the bending modulus was 13 GPa. ②HHPLA was fairly degradable in SD rats.Degradation was slower in the earlier period than that in the later period.CONCLUSION: HHPLA composite rods have some fairly good characteristics of initial mechanical strength and degradation in vivo.