课题背景：聚乙烯醇是由聚醋酸乙烯酯水解而成的一种水溶性聚合物，目前普遍被认为是良好的关节软骨替代材料。具有骨传导特性的纳米羟基磷灰石与有机质高分子聚酰胺66进行共溶而制成的高分子聚合物，是具有中国自主知识产权和国际领先水平的新型纳米粒晶的骨修复替代材料。实验旨在探讨新型生物复合材料聚乙烯醇/纳米羟基磷灰石+聚酰胺66修复关节软骨及软骨下骨缺损的效果。

应用要点：①聚乙烯醇/纳米羟基磷灰石+聚酰胺66生物复合材料在修复关节软骨及软骨下骨缺损时，与周边关节软骨相容性好，周边软骨未见退行性变，Ⅱ型胶原分泌正常，表现出了良好的生物相容性。②聚乙烯醇/纳米羟基磷灰石+聚酰胺66复合材料植入动物体内后，随着周边软骨下骨成分逐渐向下层材料长入，形成牢固的生物自锁固定，对上层材料起到了良好的支撑作用，同时也解决了材料的远期稳定性问题。

同行评价：人工软骨作为替代材料应用于关节软骨缺损的修复目前在临床上仍存在不能高质量地修复关节软骨缺损并达到很好的远期疗效。实验将具有良好的生物力学性能的聚乙烯醇水凝胶、具有骨传导特性的纳米级羟基磷灰石以及具有高强度、高韧性和良好稳定性的聚酰胺66材料复合，形成新型人工骨仿生材料并植入动物体内，考察了复合材料植入兔膝关节后动物的生物学行为及关节腔内的变化，以及关节局部组织形态学变化和材料植入动物体内后的稳定性，得到了很有意义的结果。

摘要

背景：聚乙烯醇(Polyvinyl alcohol hydrogel，PVA)水凝胶目前普遍被认为是关节软骨良好的替代材料，纳米羟基磷灰石(nano-hydroapatite，n-HA)修复骨缺损已取得公认，聚酰胺66(PA66)是一种具有高强度、高韧性和良好稳定性的聚合物，在工程和医学领域已获得广泛应用。
目的：实验仿照关节软骨理化特性，制备新型生物复合材料PVA/n-HA+PA66，观察新型生物复合材料PVA/n-HA+PA66修复兔关节软骨及软骨下骨缺损的效果。
设计、时间及地点：随机分组设计的动物对照实验，于2006-07/2007-07在四川大学华西医院骨科组织工程实验室完成。
材料：成年健康新西兰大白兔72只，在兔股骨关节面上打孔（5 mm×5 mm×5 mm）制备兔关节软骨及软骨下骨缺损模型。PVA/n-HA+PA66生物复合材料由四川大学纳米分析测试中心提供，规格：直径5 mm，高5 mm，圆柱体，上层PVA高度为1.5 mm，乳白色，光滑，质韧，下层n-HA+PA66表面粗糙，质硬，高度为3.5 mm。PVA为多孔网状结构，孔径为5~40 μm，孔隙率为75.3%，含水率为71.6%，n-HA+PA66为多孔网状结构，孔径100~400 μm，孔隙率61.7%。
方法：72只模型兔按随机数字表法分为3组，PVA/n-HA+PA66植入组、单纯PVA植入组、空白对照组，每组24只。PVA/n-HA＋PA66植入组在兔关节软骨及软骨下骨缺损处植入PVA/n-HA＋PA66材料，单纯PVA植入组在缺损处植入PVA材料、空白对照组不做任何处理。
主要观察指标：植入4，8，12，24周后观察兔行为形态、兔膝关节局部组织形态学变化，免疫组织化学染色检测Ⅱ型胶原，扫描电镜观察生物材料与周边软骨及软骨下骨连接界面的反应。
结果：72只兔全部进入结果分析。①术后大体形态观察伤口无感染，关节活动度好。②植入后24周，PVA/n-HA+PA66植入组下层材料与周边组织融为一体，周边软骨未见明显退行性变；单纯PVA植入组PVA与部分周边软骨间隙加大，周边软骨部分退行性变；空白对照组缺损部位大部分已钙化。③植入后24周，PVA/n-HA+PA66植入组PVA周边软骨Ⅱ型胶原阳性染色，PVA边缘及表面Ⅱ型胶原阳性染色增多；单纯PVA植入组PVA与周边组织间隙中Ⅱ型胶原阳性染色有少量增加，PVA表面阳性染色减弱，周边软骨阳性染色减弱；空白对照组缺损处表面组织中Ⅱ型胶原染色减低，周边关节软骨染色减低。④植入后24周，扫描电镜见PVA/n-HA+PA66植入组下层材料网孔中充满大量类骨质成分，上层材料PVA与下层材料嵌合紧密；单纯PVA植入组材料周边骨质有部分退缩，间隙加大；空白对照组缺损处下部由骨质充填，上部为纤维瘢痕样组织，组织结构排列紊乱。
结论: 双相生物复合材料PVA/n-HA+PA66具有良好的组织相容性及良好的替代关节软骨及软骨下骨的功能。
关键词:生物复合材料；关节软骨；软骨下骨；修复

郭涛，杨天府，肖杰，龙浩 ，陈艺新，裴福兴，李玉宝.新型生物复合材料聚乙烯醇/纳米羟基磷灰石+聚酰胺66修复关节软骨及软骨下骨缺损[J].中国组织工程研究与临床康复，2008，12(14):2623-2627
[www.zglckf.com/zglckf/ejournal/upfiles/08-14/14k-2623(ps).pdf]

Repair of articular cartilage and subchondral defects with a new type biological composite material polyvinyl alcohol/nano-hydroxyapatite and polyamide 66

Abstract

BACKGROUND:Polyvinyl alcohol (PVA) hydrogel has been generally considered as a good substitute material of articular cartilage, nano-hydroxyapatite (n-HA) is widely used to repair bone defect, and polyamide 66 (PA66) polymer has achieved an extensive application in the fields of engineering and medicine owing to its high intensity, strong tenacity and good stability.
OBJECTIVE: Based on physico-chemical characteristics of articular cartilage, this study is designed to prepare a new type of biomaterial composite PVA/n-HA+PA66 and observe the repair of articular cartilage and subchondral defects in rabbit knee joints with PVA/n-HA+PA66.
DESIGN, TIME AND SETTING: The animal controlled experiment was performed according to random grouping in Tissue Engineering Laboratory, Department Orthopedics, West China Hospital, Sichuan University from July 2006 to July 2007.
MATERIALS: Seventy-two healthy adult New Zealand rabbits were used for the models of articular cartilage and subchondral defects by perforating (5 mm×5 mm×5 mm) on the femoral bone joint. PVA/n-HA+PA66 was offered by the Analytical and Testing Center of Sichuan University, its specification was cylinder, diameter 5 mm, height 5 mm; upper layer (PVA) height 1.5 mm, ivory, smooth and tenacious; lower layer (n-HA+PA66) height 3.5 mm, rough and stiff. PVA was porous network, with pore diameter 5-40 μm, porosity 75.3% and water ratio 71.6%; n-HA+PA66 was also porous, with pore diameter 100-400 μm and porosity 61.7%.
METHODS: Seventy-two rabbit models were at random divided into 3 groups (n=24): PVA/n-HA+PA66 implant group, PVA implant group, and control group. Materials were implanted into articular cartilage and subchondral defects in rabbits, while no treatment was given in the control group.
MAIN OUTCOME MEASURES: The macroscopic and histological evaluations of rabbit knee joints were performed at 4, 8, 12 and 24 weeks postoperatively. Ⅱ collagen was measured by immunohistochemical dyeing. The interfaces of biomaterial implants with articular cartilage and subchondral bone were observed by scanning electron microscope.
RESULTS: All 72 rabbits were involved in the result analysis.①No infection was observed in all animals with good motion of joints.②At 24 weeks postoperatively, the lower layer materials of PVA/n-HA+PA66 got well with surrounding cartilage, which did not degenerate obviously; In PVA implant group, the gap was enlarged between PVA and partly of surrounding cartilage, which did degenerate; Most of the defects had been calcified in the control group.③At 24 weeks postoperatively,Ⅱ collagen immunohistochemical dyeing were positive in gaps between PVA and surrounding cartilage, and in PVA surface; In PVA implant group, positive dyeing was a little increased in gaps between PVA and surrounding cartilage, but weakened in PVA surface and surrounding cartilage; Reduced dyeing was observed in both the defect surface and surrounding cartilage in the control group.④At 24 weeks postoperatively, lower layer materials of PVA/n-HA+PA66 were full of bone tissues under scanning electron microscope, and were closely connected with upper layer material PVA; In PVA implant group, bone tissue around the materials receded, and the gap became bigger; The interior defects in the control group were filled with bone tissues, while superior defects with fibrous scar-like tissues that arranged in disorder.
CONCLUSION: The diphase biological composite materials PVA/n-HA+PA66 have good function for replacing articular cartilage and subchondral, with good biocompatibility.

Guo T, Yang TF, Xiao J, Long H, Chen YX, Pei FX, Li YB.Repair of articular cartilage and subchondral defects with a new type biological composite material polyvinyl alcohol/nano-hydroxyapatite and polyamide 66.Zhongguo Zuzhi Gongcheng Yanjiu yu Linchuang Kangfu 2008;12(14):2623-2627 [www.zglckf.com/zglckf/ejournal/upfiles/08-14/14k-2623(ps).pdf]