PLGA涂层处理的nHA-Mg多孔复合材料对兔颌骨缺损的修复作用

发布时间：2018-04-19 19:58

本文选题：纳米羟基磷灰石 + 镁　；参考：《吉林大学》2017年硕士论文

【摘要】：口腔颌面部先天性畸形、肿瘤、外伤以及慢性炎症等均会造成颌骨缺损,利用骨组织工程支架材料修复骨缺损是当前研究的热点。纳米羟基磷灰石(nano-hydroxyapatite,nHA)作为常见的骨缺损植入材料,具有良好的结构和成骨作用,但存在机械强度低、韧性差的缺点。金属Mg作为植入材料机械性能优越,成骨效应良好,但是单纯Mg代谢速度很快并且没有适合组织长入的空间结构。因此,本研究设计将nHA和Mg复合,可以提高合金材料的成骨作用,增加材料的机械强度。而复合材料表面采用聚乳酸-羟基乙酸共聚物(poly lactic acid/glycolic acid,PLGA)修饰可以减缓Mg的降解速率。通过前期实验表明本研究的复合材料空间结构良好,强度适宜,无细胞毒性。因此,本实验将复合材料植入到兔下颌骨缺损的动物模型中,观察对骨修复的作用,为复合材料的进一步研究提供实验依据。本实验将18只日本大耳白兔建成双侧下颌骨10 mm×5 mm×1mm骨缺损动物模型,随机选取9只左侧植入表面经PLGA处理的nHA-Mg复合材料作为实验组,右侧不植入任何材料作为空白对照组;剩余9只左侧植入nHA-Mg复合材料作为阳性对照组,右侧同样作为空白对照组。白兔4、8、12周分次处死,截取缺损区域下颌骨,进行影像学和组织学观察,并比较各组新生骨小梁面积占骨组织面积的百分数以及实验组和阳性对照组材料的剩余量。与阳性对照组和空白对照组比较,实验组新生骨小梁面积所占百分数最大(P0.05),而阳性对照组与空白对照组比较差异无统计学意义(P0.05)。影像学观察,实验组有新骨形成,并且效果明显优于阳性对照组和空白对照组。石蜡切片观察,实验组可见血管组织和新生的骨小梁,成骨细胞聚集在骨小梁周围,大量骨陷窝位于骨小梁上,内含有骨细胞,骨形成处于活跃期。随时间延长,新生骨小梁增粗,排列更致密,有改建为板层骨趋势。硬组织磨片观察,实验组材料剩余量多于阳性阳性对照组。综上所述,表面经PLGA处理的nHA-Mg多孔复合材料,其降解速率得到有效控制,并且材料具有促进成骨和引导骨再生的作用。
[Abstract]:Oral and maxillofacial congenital deformities, tumors, trauma and chronic inflammation can cause jaw defects. Nano-hydroxyapatite nano-hydroxyapatite (HA), as a common bone defect implant material, has good structure and osteogenesis, but it has the disadvantages of low mechanical strength and poor toughness. The metal mg has excellent mechanical properties and good osteogenic effect, but the metabolism rate of mg is very fast and there is no space structure suitable for tissue growth. Therefore, the composite of nHA and mg can improve the osteogenesis and increase the mechanical strength of the alloy. On the surface of the composite, poly lactic acid/glycolic acidate modified with poly lactic acid-glycolic acid copolymer could slow down the degradation rate of mg. The experimental results show that the composite has good spatial structure, suitable strength and no cytotoxicity. Therefore, the composite material was implanted into the rabbit mandibular defect animal model, and the effect on bone repair was observed to provide experimental basis for the further study of the composite material. In this experiment, 18 Japanese white rabbits were used to establish bilateral mandibular bone defect models with 10 mm 脳 5 mm 脳 1mm bone defect. Nine nHA-Mg composites were randomly selected as experimental group, and no material was implanted into the right side as blank control group. The remaining 9 nHA-Mg composites were implanted as the positive control group and the right side as the blank control group. The rabbits were killed in 12 weeks. The mandible of the defect area was cut off, and the imaging and histological observation were performed. The percentage of the new bone trabecular area to the bone tissue area and the remaining amount of the materials in the experimental group and the positive control group were compared. Compared with the positive control group and the blank control group, the percentage of new bone trabecular area in the experimental group was the largest (P 0.05), but there was no significant difference between the positive control group and the blank control group (P 0.05). Imaging observation showed that the experimental group had new bone formation, and the effect was better than that of the positive control group and the blank control group. In the experimental group, vascular tissue and new bone trabeculae were observed. The osteoblasts gathered around the trabeculae, a large number of bone lacunae were located on the trabeculae, bone cells were found in the experimental group, and bone formation was active. As time goes on, the trabeculae of new bone become thicker and denser, and have the tendency of remodeling into lamellar bone. The material surplus in the experimental group was more than that in the positive control group. In conclusion, the degradation rate of nHA-Mg porous composites treated with PLGA was effectively controlled, and the material promoted osteogenesis and guided bone regeneration.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R783.1

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