纳米双相陶瓷人工骨的成骨及降解

背景：烧结后的纳米羟基磷灰石结晶度很高,在体内很难降解;纳米β-磷酸三钙的降解速度太快,不利于体内生物组织在材料上附着,不利于引导成骨。 目的：观察纳米羟基磷灰石/纳米β-磷酸三钙双相陶瓷人工骨的成骨及降解性能。 方法：将36只青紫蓝兔随机分为实验组、对照组及空白组,制作左侧挠骨缺损模型,实验组与对照组分别植入纳米羟基磷灰石/纳米β-磷酸三钙双相陶瓷人工骨、纳米羟基磷灰石人工骨,空白组不植入任何材料。术后4,8,12周观察成骨和材料降解情况。 结果与结论：①术后12周时X射线：实验组可见材料基本降解,连续性骨痂通过骨缺损部位。对照组材料未见明显降解,骨缺损处有骨痂修复。空白组骨缺损未见修复。②术后12周时组织学观察：实验组材料孔隙内以骨细胞和成骨细胞为主,有少量软骨细胞,出现散乱的骨松质,材料完全降解。对照组材料孔隙内以骨细胞为主,有少量成骨细胞和软骨细胞,材料未见明显降解。空白组可见纤维结缔组织及胶原纤维。③术后12周时扫描电镜观察：实验组材料降解,骨缺损部位被新生骨松质取代。对照组材料未见降解,骨缺损部位大都被新生骨松质取代。空白组无明显骨重建。表明纳米羟基磷灰石/纳米β-磷酸三钙双相陶瓷人工骨具有良好成骨能力及降解性能。     

聚乳酸-乙醇酸共聚物-磷酸三钙-骨形态发生蛋白2人工骨结合肌肉移植修复骨缺损

背景：大段骨缺损修复多以植骨为主,如果能将带血运的组织与人工骨同时植入,理论上更有利于新生组织血运建立及人工骨的爬行替代重建。 目的：观察聚乳酸-乙醇酸共聚物-磷酸三钙-骨形态发生蛋白2人工骨结合自体带血供自体肌肉移植修复大段骨缺损的效果。 方法：手术造成30 mm绵羊大段桡骨缺损,抽签随机分为3组：实验组植入聚乳酸-乙醇酸共聚物-磷酸三钙-骨形态发生蛋白2人工骨及自体带血运的屈指长肌,对照组仅植入聚乳酸-乙醇酸共聚物-磷酸三钙-骨形态发生蛋白2人工骨,空白对照组未植入任何材料。3组均以钢板固定骨缺损区,术后24周进行X射线检测及组织学观察。 结果与结论：实验组桡骨缺损处完全成骨修复,皮质骨与髓腔轮廓清晰,骨痂为较成熟板层骨;对照组骨缺损基本完全修复,但新生骨密度及髓腔轮廓清晰度及骨痂成熟度均不如实验组;空白对照组无有效骨痂形成,缺损区被大量纤维组织填充。说明聚乳酸-乙醇酸共聚物-磷酸三钙-骨形态发生蛋白2人工骨结合自体带血供肌肉移植能够很好修复绵羊桡骨30 mm的大段骨缺损。     

β-磷酸三钙煅烧骨修复兔股骨远端骨缺损

背景：自体骨兼具骨引导和骨诱导特性而成为修复骨缺损的金标准,但其来源有限,促使研究人员去寻找各类骨移植替代物。 目的：观察β-磷酸三钙煅烧骨作为骨移植替代物修复兔股骨远端骨缺损的效果。 方法：制备直径5 mm,深12 mm的兔股骨远端骨缺损模型,实验侧骨缺损部位植入β-磷酸三钙煅烧骨试件,对照侧仅制造骨缺损模型,不植入任何材料。观察实验动物手术切口局部情况,并制备病理切片,观察材料植入后的骨长入情况。 结果与结论：骨缺损部位植入β-磷酸三钙煅烧骨试件后,实验动物的切口愈合良好,在术后4周可以观察到骨缺损周边开始形成新骨,并随着时间的延长新骨形成量逐渐增多,至术后12周时,材料中心部位也可见新骨长入,材料逐渐降解,而对照侧直至术后12周时骨缺损部位仍无新骨长入。结果显示β-磷酸三钙具备良好的成骨性能,是一种优良的骨移植替代物。     

复合同种异体成骨细胞的β-磷酸三钙人工骨修复桡骨缺损

背景：作为骨支架材料,β-磷酸三钙具有良好的生物相容性、骨诱导性及生物力学性能。 目的：探讨β-磷酸三钙复合同种异体成骨细胞修复兔桡骨节段性骨缺损的效果。 方法：建立45只兔单侧桡骨骨缺损模型,随机分为3组,实验组缺损区植入复合同种异体成骨细胞的β-磷酸三钙,对照组缺损区植入β-磷酸三钙,空白对照组缺损区不植入任何材料。植入后4,8,16周观察新骨生成情况,通过形态学、X射线等观察指标客观评价各组成骨及骨缺损修复能力。 结果与结论：随着修复时间的延长,实验组骨缺损逐渐修复,至16周时X射线见支架与宿主骨之间的骨痂已完全骨化,骨缺损完全修复;组织学见缺损区皮质骨连续,髓腔再通,并且不同时间点实验组修复效果明显优于对照组与空白对照组(P < 0.01)。表明复合同种异体成骨细胞的β-磷酸三钙人工骨具有良好的成骨能力,有引导组织再生、防止骨不连的作用。     

多孔磷酸三钙修复良性骨肿瘤骨缺损的临床研究

目的评价多孔磷酸三钙(Tricalcium Phosphate,TCP)治疗良性或侵袭性骨肿瘤骨缺损临床效果。方法 2007年9月至2010年1月对19例良性或侵袭性骨肿瘤患者采用多孔磷酸三钙修复骨缺损,其中男12例,女7例。年龄3~58岁,平均年龄22.4岁。随访3~30月,平均13月。采用VAS评分反应疼痛缓解程度,X线检查并Lane-Sandhu评分评定骨愈合情况,分析X片中植骨区灰度变化评估TCP的降解情况。结果 VAS评分术前、术后1周、术后12周、术后24周各组间总体差别比较<0.01,说明术后疼痛逐渐缓解。Lane-sandhu评分三个时段差异<0.001,说明人工骨随时间推移有明显的骨修复效果。认为手术中应当将多孔TCP人工骨松散放置,不要施加任何挤压力。结论多孔磷酸三钙人工骨可以用作良性或侵袭性骨肿瘤骨缺损的修复。     

TCP-PMMA骨水泥-骨界面强度变化的研究

目的探讨具有生物活性的三磷酸三钙骨水泥(TCP-PMMA)用于人工关节固定的可能性。方法25只大白兔随机分成5组,在左右侧股骨远端均造成一标准骨缺损模型(直径6mm,长12mm),实验侧置入TCP-PMMA骨水泥,TCP占TCP-PMMA总重量的35%;对照侧为单纯骨水泥PMMA。在术后2、4、8、12、16周,分别进行骨-骨水泥界面强度测定。结果TCP-PMMA骨水泥侧,界面抗剪强度在植入后2周略有下降,但植入后4周至16周逐渐增强,特别是12周至16周,强度明显高于2、4、8周(P<0.05);并且12和16周的界面抗剪强度明显高于纯骨水泥对照侧。对照侧,在观察期2至16周内,界面抗剪强度无明显变化(P>0.05)。结论TCP-PMMA骨水泥-骨界面强度高于单纯骨水泥;在416周内,其强度随时间的延长而逐渐增强。     

磷酸三钙陶瓷材料形状对大鼠体内成血管化的影响

背景：组织工程人工骨支架材料的大体和微观结构可加速血管化进程。 目的：观察不同形状β-磷酸三钙陶瓷骨在体内的血管化程度,探索载体材料形状对体内血管化的影响。 方法：将柱状和管状两种β-磷酸三钙陶瓷骨材料分别植入SD大鼠两侧腰背筋膜下。 结果与结论：①同位素扫描结果：术后第3,6,12周,管状β-磷酸三钙陶瓷骨材料放射性核素骨显影放射性计数明显高于柱状β-磷酸三钙陶瓷骨材料(P < 0.05),并且随着时间的延长,两组放射性核素骨显影放射性计数均呈上升趋势。②扫描电镜观察结果：第3周时,材料外形保持良好,宿主纤维组织和血管由材料外周向内生长;术后6周时,管状材料内小血管增生活跃,且分布比较均匀,柱状材料血管增生主要集中在外周部分;术后12周时,两组材料血管化程度更高,管状材料外周及中心部位均可见较为成熟的纤维组织和丰富血管网,但柱状材料纤维组织和血管主要集中在外周部分,中轴部分较少。表明管状三维结构β-磷酸三钙陶瓷骨材料较柱状材料更利于体内血管化。     

β-磷酸三钙/聚乳酸-聚羟基乙酸/异烟肼/左氧氟沙星缓释材料的成骨检测

背景：在聚乳酸-聚羟基乙酸中加入β-磷酸三钙可调控其降解速率和强度。 目的：观察β-磷酸三钙/聚乳酸-聚羟基乙酸/异烟肼/左氧氟沙星缓释材料修复兔股骨髁骨缺损的效果。 方法：制作兔右股骨髁直径5 mm、长10 mm的圆柱形骨缺损模型,随机分3组,其中两组分别于骨缺损处植入β-磷酸三钙/聚乳酸-聚羟基乙酸材料和β-磷酸三钙/聚乳酸-聚羟基乙酸/异烟肼/左氧氟沙星缓释材料,空白对照组不植入任何材料。通过影像学、大体标本、组织学检查评价骨缺损修复效果。 结果与结论：术后12周时,β-磷酸三钙/聚乳酸-聚羟基乙酸材料组和β-磷酸三钙/聚乳酸-聚羟基乙酸/异烟肼/左氧氟沙星缓释材料组骨缺损都得到修复,两组新骨占缺损区面积差异无显著性意义(P > 0.05),空白对照组骨缺损未修复。表明β-磷酸三钙/聚乳酸-聚羟基乙酸/异烟肼/左氧氟沙星缓释材料可以很好修复兔股骨髁缺损。     

羟基丁酸-羟基戊酸纳米纤维材料修复胫骨缺损

背景：羟基丁酸-羟基戊酸纳米纤维材料促进骨组织再生的体内实验研究较少,且研究结果有争论。 目的：观察羟基丁酸-羟基戊酸纳米纤维材料修复骨缺损的能力。 方法：随机选取45只新西兰兔,制备单侧胫骨中上段骨缺损模型,随机均分为3组,实验组植入羟基丁酸-羟基戊酸纳米纤维材料,对照组植入β-磷酸三钙人工骨,空白组不植入任何材料。在术后相应时间段分别进行X射线摄片,组织学检查,扫描电镜观察其成骨能力、生物降解性、生物相容性等指标。 结果与结论：术后4~8周,实验组骨缺损植入材料处片状密度增强,截骨两端骨质向缺损区生长,骨皮质不连续,仍见骨性缺损,术后8~12周,新生皮质骨与宿主皮质骨自然连接,骨缺损完全修复。术后4,8周,实验组与对照组在新生骨的形成及修复骨缺损方面相差不明显(P > 0.05),12周时,实验组具备更好的成骨能力,与对照组比较差异有显著性意义(P < 0.05)。结果可见羟基丁酸-羟基戊酸纳米纤维材料具有良好的生物相容性及骨传导性,是一种良好的骨组织工程支架材料。     

快速成型聚乳酸-聚羟乙酸/磷酸三钙支架修复兔桡骨缺损

背景：理想的骨修复材料除必须具有生物相容性、可吸收性、利于血管化及迅速被新生组织替代的孔隙率,还需要有与骨组织相似三维结构。 目的：检验快速成型工艺制作的聚乳酸-聚羟乙酸/磷酸三钙支架复合骨形态发生蛋白修复兔桡骨缺损的效果。 方法：将乳酸乙醇酸共聚物溶于1,4-二氧六环中并混合粉末状磷酸三钙制备成液态的浆料,放入生物材料快速成形机TissFormTM制备出直径5 mm,长15 mm的圆柱形人工骨载体材料。按每个材料15 mg的标准,采用预湿、负压复合骨形态发生蛋白、冻干3步处理,制备出活性人工骨材料。健康新西兰大白兔20只,制备右前肢桡骨中上段15 mm骨缺损模型,实验组和对照组分别植入复合骨形态发生蛋白的活性人工骨和未复合骨形态发生蛋白的单纯支架。通过影像学、组织学、材料降解及骨密度评价修复兔桡骨缺损的效果。 结果与结论：12周时实验组骨缺损愈合,新生骨痂连接缺损断端并塑形,支架材料近于完全降解,各检测指标与对照组比较差异均有显著性意义,对照组骨缺损内未见新骨形成。结果表明复合骨形态发生蛋白的聚乳酸-聚羟乙酸/磷酸三钙支架可以很好的修复兔15 mm骨缺损,且降解速度与成骨速度匹配良好。     

Bone in-growth induced by biphasic calcium phosphate ceramic in femoral defect of dogs

Biphasic calcium phosphate (BCP) ceramics consisting of hydroxyapatite (HA) and tricalcium phosphate (TCP) has been used as a bone graft material during the last decade. In this paper, we report the bone in-growth induced by BCP ceramic in the experimentally created circular defects in the femur of dogs. This BCP ceramic consists of 55% hydroxyapatite (HA) and 45% b-tricalcium phosphate (TCP) prepared in situ by the microwave method. The defects were created as 4-mm holes on the lateral aspect of the femur of dogs and the holes were packed with the implant material. The defective sites were radiographed at a period of 4, 8, and 12 weeks postoperatively. The radiographical results showed that the process of ossification started after 4 weeks and the defect was completely filled with new woven bone after 12 weeks. Histological examination of the tissue showed the formation of osteoblast inducing the osteogenesis in the defect. The collageneous fibrous matrix and the complete Haversian system were observed after 12 weeks. The blood serum was collected postoperatively and biochemical assays for alkaline phosphatase activity were carried out. The measurement of alkaline phosphatase activity levels also correlated with the formation of osteoblast-like cells. This microwave-prepared BCP ceramic has proved to be a good biocompatible implant as well as osteoconductive and osteoinductive materials to fill bone defects.     

Bioactivity and osseointegration study of calcium phosphate ceramic of different chemical composition

Synthetic hydroxyapatite (HA) and tricalcium phosphate (TCP) are promising bone-substitute materials in the orthopaedic and dental fields, as their chemical composition is similar to that of bone. This study investigated the osseointegration performance of carbonated biphasic calcium phosphate (CBCP) ceramics containing carbonated hydroxyapatite and tricalcium phosphate prepared by microwave irradiation, in femoral defects of dogs. The defects were created as 3-mm holes on the lateral aspect of femur and filled with the implant material. The serum was collected postoperatively and biochemical assays for alkaline phosphatase activity levels were carried out. The animals' defective sites were radiographed at 4, 8, and 12 weeks. The radiographic results showed that the process of ossification started after 4 weeks and the defect was completely filled with new bone after 8 weeks. Histological examination of the tissue showed the osteoblastic activity inducing the osteogenesis in the defect. The complete haversian system with osteoblastic and osteoclastic activity and bone remodelling process were observed after 12 weeks. The alkaline phosphatase activity levels also correlated with the formation of osteoblast cells. This calcium phosphate ceramic has proved to work well as a biocompatible implant and as an osteoconductive and osteoinductive material for the filling of bone defects.     

Stimulation of bone formation with an in situ setting tricalcium phosphate/rhBMP-2 composite in rats

The aim of the study was to determine bone-regenerative effects of an in situ setting tricalcium phosphate (TCP) cement combined with rhBMP-2 and to compare it with autologous bone graft. A trepanation defect of 1.5 mm in the femur diaphysis of Sprague-Dawley rats was filled with an in situ setting TCP cement combined with 0, 0.25, 2.5, or 25 microg of rhBMP-2, an autologous bone graft, or left empty. The rats were euthanized after 1 and 3 weeks and examined by radiography, histology, histomorphometry, and bending tests. All TCP groups with or without BMP-2 showed a good bony ingrowth with a close bone-cement contact. Histomorphometric analysis showed no increase of new bone formation in the defect, but a dose-dependent increase in callus formation with a maximum at 25 microg of rhBMP-2. As shown with intravital fluorochrome staining, new bone formation started earlier using rhBMP-2. Bone strength, measured in a three-point bending test and expressed in percentage of the contralateral healthy femur, was 75% for TCP + 25 microg rhBMP-2, 44% for TCP + 2.5 microg rhBMP-2, and 34% for autologous bone graft. TCP particles were detectable in all groups after 3 weeks. Callus formation and bending strength of the TCP + 25 microg rhBMP-2 group was superior to autologous bone graft. So TCP/rhBMP-2 composites may prove to be an effective substitute for autologous bone grafts.     

异位预成中心性血管化人工骨的构建

背景：血管化在骨形成和改建中起重要作用,生物活性陶瓷β-磷酸三钙的多孔性及可吸收性为血管植入构建血管化人工骨提供可能。 目的：探讨异位预成中心性血管化人工骨的建立、血供及人工骨血管化的机制,为异位预成中心性血管化人工骨的临床应用提供理论依据。 方法：选择新西兰兔的腰背动脉解剖分离形成血管束,实验侧将血管束移入人工骨侧槽内,并用自体微小骨颗粒填满,埋入背阔肌肌袋内,以未做血管束植入动物作为对照。术后4,6,8周行大体形态学和组织学检查。 结果与结论：血管束植入组人工骨形成类似滋养孔的结构,血管丰富,血管通畅。中心性血管化人工骨各处均有大量血管新生,4-8周充满全层,4周时开始出现新生骨和骨代谢,12周新生骨更趋于成熟。对照组仅少量血管自周围长入,新生骨少且不成熟。结果表明中心性血管化人工骨可显著促进人工骨血管化。该模型有望成为磷酸钙人工骨的临床应用的新方式。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程全文链接：     

Repair of canine mandibular bone defects with bone marrow stromal cells and porous beta-tricalcium phosphate

Tissue engineering has become a new approach for repairing bone defects. Previous studies have been limited to the use of slow-degradable scaffolds with bone marrow stromal cells (BMSCs) in mandibular reconstruction. In this study, a 30 mm long mandibular segmental defect was repaired by engineered bone graft using osteogenically induced autologous BMSCs seeded on porous beta-tricalcium phosphate (beta-TCP, n=5). The repair of defects was compared with those treated with beta-TCP alone (n=6) or with autologous mandibular segment (n=4). In the BMSCs/beta-TCP group, new bone formation was observed from 4 weeks post-operation, and bony-union was achieved after 32 weeks, which was detected by radiographic and histological examination. In contrast, minimal bone formation with almost fibrous connection was observed in the group treated with beta-TCP alone. More importantly, the engineered bone with BMSCs/beta-TCP achieved a satisfactory biomechanical property in terms of bending load strength, bending displacement, bending stress and Young's modulus at 32 weeks post-operation, which was very close to those of contralateral edentulous mandible and autograft bone (p>0.05). Based on these results, we conclude that engineered bone from osteogenically induced BMSCs and biodegradable beta-TCP can well repair the critical-sized segmental mandibular defects in canines.     

Bone and Ceramic Interaction in the Bone Union Process

This study applied an experimental rat model and ceramic as an artificial matrix to explore the ultrastructural development of new bone production in tibia defects. By X-ray diffraction control or energy-dispersive X-ray analysis the nature of ceramic was verified and routine histology and TEM investigation were used to demonstrate bone - ceramic interaction. The results show that biphasic ceramic can promote bone growth in an osseous defect and is therefore an alternative to autogenous bone matrix. The porousity and bioactivity of the biphasic ceramic enhanced bone formation and provided a scaffold for new lamellar bone invasion.     

组织工程骨-假体界面微观结构与元素分析的意义

目的研究假体-组织工程骨界面的微观结构和钙磷元素及构成比动态变化及意义。方法取新西兰大白兔15只,将兔骨髓间充质干细胞培养、扩增及诱导后,与珊瑚羟基磷灰石复合构建组织工程骨;双侧股骨髁分别制作一0.5cm×1.2cm骨缺损,骨缺损中央植入0.2cmx1.0cm钛合金植入体,左侧植入体周围植入组织工程骨,右侧仅植入珊瑚羟基磷灰石为对照,于术后4周、8周和l2周分别行X线检查、扫描电镜及能谱分析观察植入体表面微观结构和钙磷元素百分含量及比值的变化。结果 X线检查示,实验组术后8-12周可见大量模糊的高密度骨痂影,缺损区与周围骨质间分界变模糊。对照组各时间点无明显变化;扫描电镜示,实验组术后8、12周植入体表面孔隙内有大量无定形物质,而对照组未见有无定形物质。能谱分析示,不同时间点实验组较对照组内钙、磷元素百分含量高,有显著性差异（〈0.05）,随着时间的变化实验组和对照组Ca、P百分含量都呈增高的趋势,但12周和8周相比无显著性差异（〉0.05）。实验组内钙磷比值随时间变化有逐渐增大趋势,8周时达峰值,8周后缓慢下降。结论假体-组织工程骨界面钙、磷元素及构成比的动态变化表明骨整合的形成,并随着时间的延长骨改建逐步增加。     

Hydrolysis of tetracalcium phosphate under a near-constant-composition condition--effects of pH and particle size

Tetracalcium phosphate (TTCP) is a component of a number of calcium phosphate cements used clinically for bone defect repairs. The strength, phase composition, and solubility of the set cement are highly dependent on the reactions of the cement components during setting. This study investigated hydrolysis reactions of TTCP under solution compositions chosen to mimic the compositions of the cement liquid during setting. The study utilized a pseudo-constant-composition technique that allowed both the rate and stoichiometry of the reaction to be determined while the reaction proceeded under a specific, constantly held solution pH, thereby keeping a constant calcium-to-phosphate ratio in solution. The hydrolysis experiments were conducted using either a fine (median particle size 3.5 microm) or coarse (median particle size 13.2 microm) TTCP powder at pH 7, 8 and 10. Low crystalline calcium (Ca)-deficient hydroxyapatite (HA) was the product in all experiments. Both the solution pH and TTCP particle size produced significant effects on all aspects of the hydrolysis reaction. At a given pH, the fine TTCP produced a HA product with a greater Ca deficiency than did the coarse TTCP. For a given particle size, the Ca deficiency generally decreased with increasing pH. Hydrolysis reaction rate generally decreased with increasing pH or TTCP particle size. At pH 7 and 8, the solution was undersaturated with respect to TTCP and supersaturated with respect to HA, suggesting that the reaction rate was limited by TTCP dissolution. In contrast, at pH 10, the solution was approximately saturated with respect to TTCP and highly supersaturated with respect to HA, suggesting that HA formation was the rate-determining step of the reaction. The findings provided useful insights into the setting reaction mechanisms of TTCP-containing calcium phosphate cements.