Repair of sheep metatarsus defects by using tissue-engineering technique

Tissue-engineering bone with porous β-tricalcium phosphate (β-TCP) ceramic and autologous bone marrow mesenchymal stem cells (MSC) was constructed and the effect of this composite on healing of segmental bone defects was investigated. 10-15 ml bone marrow aspirates were harvested from the iliac crest of sheep, and enriched for MSC by density gradient centrifugation over a Percoll cushion (1.073g/ml). After cultured and proliferated, tissue-engineering bones were constructed with these cells seeded onto porous β-TCP, and then the constructs were implanted in 8 sheep left metatarsus defect (25 mm in length) as experimental group. Porous β-TCP only were implanted to bridge same size and position defects in 8 sheep as control group, and 25 mm segmental bone defects of left metatarsus were left empty in 4 sheep as blank group. Sheep were sacrificed on the 6th, 12th, and 24th week postoperatively and the implants samples were examined by radiograph, histology, and biomechanical test. The 4 sheep in blank group were sacrificed on the 24th week postoperatively. The results showed that new bone tissues were observed either radiographic or histologically at the defects of experimental group as early as 6th week postoperatively, but not in control group, and osteoid tissue, woven bone and lamellar bone occurred earlier than in control group in which the bone defects were repaired in “creep substitution” way, because of the new bone formed in direct manner without progression through a cartilaginous intermediate. At the 24th week, radiographs and biomechanical test revealed an almost complete repair of the defect of experimental group, only partly in control group. The bone defects in blank group were non-healing at the 24th week. It was concluded that engineering bones constructed with porous β-TCP and autologous MSC were capable of repairing segmental bone defects in sheep metatarsus beyond “creep substitution” way and making it healed earlier. Porous β-TCP being constituted with autologous MSC may be a good option in healing critical segmental bone defects in clinical practice and provide insight for future clinical repair of segmental defect.     

去抗原牛松质骨块/bBMP复合材料修复兔长骨骨缺损

探讨大块异种骨的制备及其在修复节段性骨缺损中的作用。方法将大块的牛松质骨制备成消除抗原性的载体,与牛骨形态发性蛋白（ＢＭＰ）组合构成去抗原牛松质骨块／ｂＢＭＰ复合材料,采用兔桡骨１５ｍｍ节段性骨缺损模型,研究去抗原质骨块／ｂＢＭＰ复合材料在修复骨缺损中的作用。     

血管内皮祖细胞对组织工程骨成骨能力影响的实验研究

目的观察血管内皮祖细胞（EPCs）时组织工程骨修复兔桡骨大段骨缺顿时成骨能力的影响。方法自体骨髓通过不同方法的体外培养，获得EPCs厦经成骨诱导的MSCs，与DBM构建组织工程骨修复兔桡骨大段骨缺损。观察术后不同时期的影像学及骨密度改变。结果术后2周，EPCs组与对照组的X线观察厦骨密度差异无统计学意义。术后4、8、12周，EPCs组的骨密度明显高于对照组，X线示EPCs组骨痂明显多于对照组，8周可见EPCs组髓腔部分再通，对照组髓腔尚封闭。12周EPCs组新生骨密度均匀，髓腔已完全再通，对照组新生骨仍可见部分低密度区，髓腔大部分再通。术后16周，两组骨密度差异无统计学意义，X线示EPCs组新生骨已基本完成塑形，对照组髓腔完全再通，新生骨处于重建塑形期。结论EPCs可以促进组织工程骨修复大段骨缺损时的成骨能力，加速骨愈合。     

骨形态发生蛋白及多孔复合陶瓷人工骨修复长骨大段骨缺损的实验研究

目的：为研制理想的、能较快修复长骨大段骨缺损的人工骨材料。方法：将骨形态发生蛋白（BMP）和多孔复合陶瓷（PCC）结合研制成BMP／PCC人工骨,并将BMP／PCC和PCC人工骨进行兔桡骨大段骨缺损修复的对比研究。术后2、4、8、12周时取材,分别作大体、组织形态学、新骨形成定量分析及生物力学测试。结果：BMP／PCC人工骨内新骨形成量明显多于PCC人工骨、术后12周时,BMP／PCC侧植入部位的抗折强度明显高于PCC侧。结论：BMP／PCC人工骨能更快促进长骨大段骨缺损的修复,是一种较理想的人工骨材料。     

消旋聚乳酸/羟基磷灰石/脱钙骨基质人工骨修复兔桡骨大段骨缺损的实验研究

目的研制理想的,能够修复大段骨缺损的人工骨材料。方法采用乳液共混法将消旋聚乳酸(PDLLA)、羟基磷灰石(HA)、脱钙骨基质(DBM)结合,制成PDLLA/HA/DBM人工骨,并将PDLLA/HA/DBM和PDLLA进行兔桡骨大段骨缺损修复的对比研究。术后2、4、8和12周时摄X片及病理形态学观察及新骨形成定量分析。结果PDLLA/HA/DBM人工骨内新骨形成量明显多于PDLLA及空白对照组(P<0.01),且能够有效修复骨缺损。结论PDLLA/HA/DBM人工骨能促进长骨大段骨缺损的修复,是一种较理想的骨修复材料。     

Artificial bone of porous tricalcium phosphate ceramics and its preliminary clinical application

Summary The authors have prepared the artificial bone of porous tricalcium phosphate ceramics according to an appropriate formula and manufacturing technology. Physical and chemical testing shows that it possesses several distinguishing features: the communicating pores and macro/micropores; mean pore size, 380 μm (from 240 μm to 510 μm); porosity, 46.4 %; and compressive strength, 97.4 kg/cm². It consists of CaO (49.09 %) and P₂O₅ (48.84 %). The testing of its biocompatibility shows that it is devoid of systemic or local toxicity, and free of irritation or foreign body response in tissues, and it does not result in hemolysis or mutation. The new bone readily grows into its pores with direct contact to the implanted material. 11 cases of bone defects were treated with this artificial bone with satisfactory results.     

胶原/纳米磷酸三钙复合人工骨骨膜下引导成骨实验研究

将胶原 (Co)与纳米磷酸三钙 (N- TCP)复合制成复合人工骨并植入兔颅骨的骨膜下作为实验组 ,使用显微镜测微尺测量不同时间点新骨自骨表面长入材料内的高度 ,并和羟基磷灰石 (HA)组 (对照组 )作对照 ,观察 Co/N- TCP复合人工骨引导成骨能力 ,探讨其用于萎缩性牙槽嵴重建的可行性。结果发现 :各时间点实验组新骨长入高度均优于对照组 (P<0 .0 5或 <0 .0 1)。提示 :Co/N- TCP在骨表面引导成骨能力优于 HA。     

Reconstruction of orbital defect in rabbits with composite of calcium phosphate cement and recombinant human bone morphogenetic protein-2

PURPOSE Calcium phosphate cement (CPC) is a biocompatible and osteoconductive bone substitute, and recombinant human bone morphogenetic protein-2 (rhBMP-2) has strong osteoinductibility, therefore we developed a composite bone substitute with CPC and rhBMP-2 and evaluate its reconstruction effect in rabbit orbital defect. METHODS Thirty-six rabbits were randomly divided into two groups and a 5mm×5mm×2mm bone defect in the infraorbital rim was induced by surgery in each orbit (72 orbits in all). The orbital defects were treated with pure CPC or composite of CPC and rhBMP-2. The osteogenesis ability of different bone substitute was evaluated by gross observation, histological examination, histomorphometrical evaluation, compressive load-to-failure testing, and scanning electron microscope (SEM). RESULTS Gross observation showed that both bone substitutes were safe and effective for reconstruction of orbital defect. However, histological examination, histomorphometrical evaluation and SEM showed that CPC/rhBMP-2 group had faster speed in new bone formation and degradation of substitute material than CPC group. Compressive load-to-failure testing showed that CPC/rhBMP-2 group had stronger compressive strength than CPC group at every stage with significant difference (P<0.05). CONCLUSIONS Composite of CPC/rhBMP-2 is an ideal bioactive material for repairing orbital defect, with good osteoconductibility and osteoinductibility.     

Experimental Study on Low Intensity Ultrasound and Tissue Engineering to Repair Segmental Bone Defects

In order to evaluate the efficacy of low intensity ultrasound and tissue engineering technique to repair segmental bone defects, the rabbit models of 1.5-cm long rabbit radial segmental os-teoperiosteum defects were established and randomly divided into 2 groups. All defects were implanted with the composite of calcium phosphate cement and bone mesenchymal stem cells, and additionally those in experimental group were subjected to low intensity ultrasound exposure, while those in control group to sham exposure. The animals were killed on the postoperative week 4, 8 and 12 respectively, and specimens were harvested. By using radiography and the methods of biome-chanics, histomorphology and bone density detection, new bone formation and material degradation were observed. The results showed that with the prolongation of time after operation, serum alkaline phosphatase (AKP) levels in both groups were gradually increased, especially in experimental group, reached the peak at 6th week (experimental group: 1.26 mmol/L; control group: 0.58 mmol/L), suggesting the new bone formation in both two group, but the amount of new bone formation was greater and bone repairing capacity stronger in experimental group than in control group. On the 4th week in experimental group, chondrocytes differentiated into woven bone, and on the 12th week, remodeling of new lamellar bone and absorption of the composite material were observed. The mechanical strength of composite material and new born density in experimental group were significantly higher than in control group, indicating that low intensity ultrasound could not only effectively increase the formation of new bone, but also accelerate the calcification of new bone. It was concluded that low intensity ultrasound could evidently accelerate the healing of bone defects repaired by bone tissue engineering.     

Reconstruction of orbital defect in rabbits with composite of calcium phosphate cement and recombinant human bone morphogenetic protein-2

Background Calcium phosphate cement （CPC） is a biocompatible and osteoconductive bone substitute, and recombinant human bone morphogenetic protein-2 （rhBMP-2） has strong osteoinductibility, therefore we developed a composite bone substitute with CPC and rhBMP-2 and evaluate its reconstruction effect in rabbit orbital defect.Methods Thirty-six rabbits were randomly divided into two groups and a 5 mmx5 mmx2 mm bone defect in the infraorbital rim was induced by surgery in each orbit （72 orbits in all）. The orbital defects were treated with pure CPC or composite of CPC and rhBMP-2. The osteogenesis ability of different bone substitute was evaluated by gross observation, histological examination, histomorphometrical evaluation, compressive load-to-failure testing, and scanning electron microscope （SEM）.Results Gross observation showed that both bone substitutes were safe and effective for reconstruction of orbital defect. However, histological examination, histomorphometrical evaluation and SEM showed that CPC/rhBMP-2 group had faster speed in new bone formation and degradation of substitute material than CPC group. Compressive load-to-failure testing showed that CPC/rhBMP-2 group had stronger compressive strength than CPC group at every stage with significant difference （P ＜0.05）.Conclusion Composite of CPC/rhBMP-2 is an ideal bioactive material for repairing orbital defect, with good osteoconductibility and osteoinductibility.     

多孔磷酸三钙陶瓷人工骨生物降解的实验观察

将多孔磷酸三钙（ＴＣＰ）陶瓷人工骨分别浸泡在去离子水、生理盐水、碳酸盐缓冲液和乳酸缓冲液中，材料在这４种溶液中均出现持续溶解，尤以在乳酸缓冲液中的溶解速率最快。将多孔ＴＣＰ陶瓷植入Ｗｉｓｔａｒ大鼠股骨髁骨腔内，术后连续观察４０周，Ｘ线拍片显示植入材料密度降低、缺损、碎裂，部分材料消失；组织学观察见植入材料孔径扩大，被分离成片块状并被新骨包裹；形态学定量分析显示植入材料面积明显减少。结果表明植入多孔ＴＣＰ陶瓷发生了明显生物降解。     

脱钙骨基质复合牛骨形态发生蛋白修复兔桡骨缺损实验的放射学评价

目的:对异体脱钙骨基质复合BMP修复节段性骨缺损能力进行放射学评价.方法:64只新西兰大白兔采用桡骨15 mm节段性骨缺损模型,随机分为4组,A组植入异体脱钙骨基质(Demineralized BoneMatrix,DBM)与牛骨形态发生蛋白(Bovine Bone Morphogentic Protein,bBMP)复合材料,B组植入异体DBM,C组植入异体骨粒,D组为空白对照组.术后4 w、8 w、12 w、16 w,进行放射学检查和相应的组织学检查.结果异体DBM与bBMP复合材料组X线和组织学检查显示骨愈合修复情况要明显优于异体DBM组、异体骨粒组和空白对照组.结论:DBM经bBMP复合后,可提高修复骨缺损的能力,是一种较为理想、具有高效成骨活性的植骨材料.     

牡蛎壳／消旋聚乳酸复合人工骨修复兔桡骨缺损的实验研究

目的观察牡蛎壳／消旋聚乳酸复合人工骨（OPCB）修复兔桡骨节段性骨缺损的成骨能力,同时观察其在体内的生物相容性、降解情况,并评价其性能。方法应用热致相分离法（TIPS）分别制得OPCB及纯消旋聚乳酸（PDLLA）多孔材料;将27只成年新西兰白兔随机分成3组。制作1．2cm的双侧桡骨干缺损并植入上述两种材料。设立不植入任何材料的空白对照组。观察材料植入后动物的局部及全身反应。于术后6、12、侣周分别取材。作X线、大体标本及组织形态学观察,同时观察术后不同时期的组织反应、材料的降解、骨缺损的修复情况。结果OPCB及纯PDLLA植入动物体内无明显的局部不良反应,且OPCB材料修复骨缺损的能力明显强于纯PDLLA及空白对照组（P〈0．05）。术后18周时,植入OPCB材料的骨缺损基本修复,OPCB与宿主骨结合紧密;植入纯PDLLA材料的骨缺损部分修复;空白对照组则骨缺损断端只有少量骨生成。形成骨不连。同时OPCB材料植入后在6、12周分别可见吞噬有材料的巨噬细胞和多核巨细胞．18周时仍有部分复合材料未降解吸收。结论OPCB材料具备良好的生物相容性及骨缺损修复能力,是一种良好的骨组织工程修复材料。     

异种骨衍生材料修复节段性骨缺损的实验研究

目的 :评价三种异种骨衍生材料修复节段性骨缺损的成骨作用 .方法 :分别用复合型完全脱蛋白骨 (CFDB)、部分脱蛋白骨 (PDPB)、部分脱钙骨 (PDCB)修复兔桡骨节段性缺损 ,以自体髂骨和空白缺损作为对照 ,术后 4 ,8,12 ,2 4周取材 ,通过X线摄片和不脱钙硬组织切片检测 ,评价三种材料的成骨作用 .结果 :X线摄片可见 4周时材料密度较高 ;8周时材料与宿主骨交界处模糊 ;12周时材料边缘部分区域密度接近宿主骨 ;2 4周时PDPB组髓腔再通 ,PDCB组缺损区域密度大部分接近宿主骨 ,有一些高密度影 ,CFDB组缺损区域有更多高密度影 .X线片评分表明 4周和 8周时各材料组无显著差异 ;12周时PDPB组和PDCB组评分高于CFDB组 ;2 4周时评分为PDPB组 >PDCB组 >CFDB组 .经组织形态观察可见 4周和 8周新骨贴附材料生长 ,以后新骨增多 ,材料随时间推移逐渐降解吸收 ,2 4周时成骨量PDPB组 >PDCB组 >CFDB组 .结论 :PDPB修复节段性骨缺损的效果好 ,PDCB的修复效果较好 ,CFDB修复效果欠佳     

Biodegradation of Tricalcium Phosphate Ceramics by Osteoclasts

Biodegradation of tricalcium phosphate (TCP) ceramics was observed through mixed culture of osteoclasts and TCP discs in vitro in this study. Osteoclasts were isolated from newborn SD rat's marrow of long bone and cultured on TCP discs. The culture terminated at the 48th h and 96th h respectively. Under an inverted microscope, the osteoclasts imparted round or oval body with multinuclear and many thin processes. These cells were positively stained for tartrate-resistance acid phosphatase (TRAP). Scanning electron microscope showed that many resorption lacunae on TCP disc surface and their diameters were smaller than 20 μm. Osteoclasts were located in the lacunae. At the 96th h, the resorption lacunae become larger and osteoclasts showed degeneration. It is suggested that osteoclasts possess ability to re-absorb TCP ceramics under in vitro culturing condition.     

复合材料修复骨缺损血管化及结构特征变化

目的：观察骨水泥、脱钙骨基质骨粒、骨形态发生蛋白生物性复合材料修复兔尺骨骨缺损血管化及结构特征变化。方法复合材料植入实验性骨缺损部位不同时间组行印度墨汁动脉血管灌注及材料自然断面扫描电镜观察,分析其血管生成及结构特征变化。结果材料植入第２周即见材料外周及两端血管形成密集,开始向材料中长入;第４,８,１２周新生血管明显逐渐增多,且深入至材料中央,第４周原自然裂隙部分即骨水泥与骨粒间多点面状结合后其间     

骨膜移植修复骨缺损过程中微血管的重建

目的：探讨骨膜移植修复骨缺损过程中微血管的重建。方法：实验用家兔为２０只,２只用于正常桡骨血管观察,另１８只制成骨缺损模型后植入自本骨膜碎牒主后第３,５,７ｄ和第２,４,８,１２周取材,观察微血管的重建。：结果骨缺损复过程中新生血管依次经过下列变化,形成血管芽→毛刷状血管→毛刷状血管→树枝状血管→无血管软骨组织→串珠状血管→海绵状血管→网状血管。结论：新生血管在骨膜碎片移植修复骨缺损过程中的不同阶     

珊瑚／骨髓复合人工骨的实验研究

目的： 评价珊瑚／ 骨髓复合人工骨（ 简称复合骨） 的成骨效应。方法： 将复合骨植入兔背部肌袋和颅骨缺损, 以单纯珊瑚植入作对照。取材后通过组织学观察和计算机图像分析, 检测其成骨情况。结果： 复合骨植入肌袋后４ 周, 局部有骨组织形成, 而单纯珊瑚植入区未见骨组织成分。复合骨植入骨缺损后６ 周, 局部形成的骨组织量明显多于同期的珊瑚植入区（ Ｐ＜ ０－０１） 。术后１２ 周, 复合骨完全被成熟的骨组织取代, 而单纯珊瑚植入区则表现为不完全性骨修复。结论： 复合骨具有良好的骨再生和骨修复能力, 是一种较理想的骨移植替代材料。     

异种骨复合自体骨髓基质干细胞修复节段性骨缺损

目的探讨异种骨复合骨髓基质干细胞(MSCs)修复节段性骨缺损的可行性。方法将MSCs与异种松质骨在体外联合培养,兔桡骨中上段制成1.5 cm的骨-骨膜缺损模型,实验组植入复合异种骨,对照组植入单纯异种骨,空白对照组不植入任何材料,分别于术后4、8、12周各时间点行标本的组织学观察、X线片观察、透射电镜观察及骨密度测试,比较其骨缺损区骨修复情况。结果术后第12周,实验组骨缺损区完全修复,骨密度接近正常;对照组骨缺损区修复缓慢,新骨形成量少;空白对照组骨缺损区未修复。结论异种骨复合MSCs修复节段性骨缺损能力强,在成骨速度和量上明显优于单纯异种骨。     

BMP-2复合PLGA／磷酸三钙修复大段骨缺损的实验研究

目的研究骨形态发生蛋白-2（Bone Morphogenetic Protein,BMP-2）复合聚乳酸一乙醇酸共聚物（P01y-Laetide-CoGlycolic,PLGA）／磷酸三钙（Tricalcium Phosphate,TCP）修复羊大段桡骨缺损的能力。方法手术制成30mm绵羊尺、桡骨骨缺损模型,A组在桡骨缺损区植入BMP-2复合PLGA／磷酸三钙棒材,B组不植入任何材料。两组均以钢板固定桡骨缺损区。术后4、8、12、24周拍摄X片,24周时处死动物进行组织学观察。结果X线片检查示A组术后24周桡骨缺损处完全成骨修复,皮质骨与髓腔的轮廓清晰;B组无有效骨痂形成。组织学检查示A组术后24周时骨痂外层形成皮质骨,为较成熟的板层骨,与断端皮质骨完全融合,其中央可见大量骨髓组织,未见植人材料残留;B组缺损区可见大量纤维组织填充。结论BMP-2复合PLGA/磷酸三钙能很好的修复绵羊大段桡缺损,未来有望成为解决临床骨缺损的有效材料。