β-TCP降解和rhBMP-2诱导成骨的关系

探讨β-TCP的降解率是否可以影响rhBMP-2的诱导成骨量.将不同降解率的β-TCP1和β-TCP2分别与rhBMP-2复合制备成不同降解率的两种复合物,β-TCP1/rhBMP-2和β-TCP2/rhBMP-2.然后分别种植于小鼠股部肌袋中.种植后分别进行组织学检查、组织形态计量、碱性磷酸酶和降解量测定.两种复合物种植后均有软骨和骨形成,成骨量随时间推移而增加.但是,种植后8周时β-TCP1/rhBMP-2组成骨量显著高于β-TCP2/rhBMP-2组(P＜0.05).种植后4周以前两组的ALP水平均随时间推移而升高(P＜0.05),但是,在4～8周间则无明显差异.此外,种植后8周时β-TCP1/rhBMP-2的降解量显著高于β-TCP2/rhBMP-2(P＜0.05).β-TCP的降解率可以影响BMP的诱导成骨量.     

中空羟基磷灰石复合rhBMP-2修复骨缺损过程的再血管化研究

目的　探讨和观察中空羟基磷灰石复合rhBMP-2在骨缺损修复过程的再血管化。  方法　将48只成年的新西兰雄性大白兔制作成桡骨骨缺损模型,随机分3组,各组分别植入以下材料：中空HA/ rhBMP-2复合人工骨、单纯中空HA人工骨、单纯rhBMP-2。植入后于4、8、12、16周分别注射99mTc-MDP进行放射性核素骨显像并监测骨缺损修复过程中再血管化情况,同时进行大体、X线、组织学观察。  结果　术后各时间段,中空HA/ rhBMP-2复合人工骨组在X线及放射性核素聚集强度明显高于单纯中空HA人工骨组(P<0.05) ,表现为成骨代谢活跃及早期的再血管化能力。  结论　中空HA/ rhBMP-2复合人工骨具有良好的骨缺损修复能力,成骨活性持久,再血管化能力强,有望成为一种理想的骨缺损修复材料。     

碳化硅对成骨细胞增殖和分化的影响

目的研究碳化硅(SiC)的体外生物相容性,为探索SiC作为骨缺损修复材料的可行性奠定基础。方法实验组为实质SiC,对照组为致密羟基磷灰石(HA)。将取自大鼠胎鼠颅骨的成骨细胞分别接种于2组材料表面。分别采用扫描电子显微镜、四甲基偶氮唑盐(MTT)法、碱性磷酸酶(ALP)含量测定技术、流式细胞仪检测细胞周期,观察分析两种材料表面上的细胞的增殖和分化能力。结果扫描电子显微镜显示:原代成骨细胞在两种材料表面伸展良好,细胞在材料表面伸出很多伪足,并且在材料表面可见明显的细胞外基质沉积。两组材料上细胞的MTT值从1、3、5、7 d随观察时间逐渐升高,并且各个时间点实质SiC均高于致密HA,两者之间的差异有统计学意义(P<0.05)。两组材料上细胞的ALP含量从1、3、5、7 d随观察时间逐渐升高;在1、3 d时,致密HA高于实质SiC,在5、7 d时,致密HA低于实质SiC,但是两组之间的差异均无统计学意义(P>0.05)。1、3、5 d两组材料的细胞增值指数(PI)值逐渐升高,高峰出现在第5天,第7天时下降,两组材料在各个时间点的PI均接近,差异无统计学意义(P>0.05)。结论实质SiC具有与致密HA相似的良好的细胞相容性。     

Electrosprayed Hydroxyapatite on Polymer Nanofibers to Differentiate Mesenchymal Stem Cells to Osteogenesis

Abstract

Electrospraying of hydroxyapatite (HA) nanoparticles onto the surface of polymer nanofibers provides a potentially novel substrate for the adhesion, proliferation and differentiation of mesenchymal stem cells (MSCs) into bone tissue regeneration. HA nanoparticles (4%) were electrosprayed on the surface of electrospun polycaprolactone (PCL) nanofibers (420 ± 15 nm) for bone tissue engineering. PCL/HA nanofibers were comparatively characterized with PCL/Collagen (275 ± 56 nm) nanofibers by FT-IR analysis to confirm the presence of HA. Fabricated PCL/HA and PCL/Collagen nanofibers and TCP (control) were used for the differentiation of equine MSC into osteogenic lineages in the presence of DMEM/F12 medium supplemented with β-glycerophosphate, ascorbic acid and dexamethasone. Cell proliferation and differentiation into an osteogenic lineage was evaluated by MTS assay, SEM observation, ALP activity, ARS staining, quantification of mineral deposition and expression of osteocalcin. Proliferation of MSCs increased significantly (P ? 0.05) up to 12% in PCL/Collagen (day 15) compared to PCL/HA nanofibrous substrate. ALP activity was increased 20% in PCL/HA by day 10 confirming the direction of osteogenic lineage from MSCs differentiation. PCL/HA stimulated an increased mineral secretion up to 26% by day 15 on ARS staining compared to PCL/Collagen nanofibers and showing cuboidal morphology by expressing osteocalcin. These results confirmed that the specifically fabricated PCL/HA composite nanofibrous substrate enhanced the differentiation of MSCs into osteogenesis.     

Recombinant growth/differentiation factor-5 (GDF-5) stimulates osteogenic differentiation of marrow mesenchymal stem cells in porous hydroxyapatite ceramic

To evaluate the growth/differentiation factor-5 (GDF-5) in the in vivo osteogenic potential of bone marrow mesenchymal stem cells (MSCs), we subcutaneously implanted five different kinds of hydroxyapatite (HA) ceramic implants: HA alone, GDF-5/HA composites (GDF/HA), MSCs/HA composites, the MSCs/HA composites supplemented with GDF-5 (GDF/MSCs/HA), and recombinant bone morphogenetic protein-2 (BMP/MSCs/HA). Neither the HA alone nor the GDF/HA composites exhibited any bone formation at any time after implantation. At 4 weeks, the MSCs/HA composites exhibited a certain amount of bone formation in some pore areas. In contrast, at 2 weeks, the GDF/MSCs/HA composites exhibited histologically obvious de novo bone formation together with active osteoblasts in many pore areas and additional bone formation at 4 weeks. In the de novo formed bone, neither chondrocytes nor endochondral bone was detected. The GDF/MSCs/HA composites also showed high alkaline phosphatase (ALP) and osteocalcin expression determined at both the protein and gene levels and the high level of expression was well maintained even at 4 weeks. Compared with GDF/MSCs/HA, the BMP/MSCs/HA composites exhibited excellent osteogenesis with relatively early osteoblastic phenotype expression. The results indicate that GDF-5 synergistically enhances de novo bone formation capability of MSCs/HA composite and suggest that tissue-engineered GDF/MSCs/HA composites could be used as bone graft substitutes.     

3D打印技术制备新型HA/ZrO2梯度复合材料在犬股骨干骨缺损修复中的应用

目的 运用3D打印技术制备新型羟基磷灰石/二氧化锆(HA/ZrO₂)梯度复合材料,分析其性能,并观察其修复比格犬股骨干骨缺损的能力。方法 随机抽取6月龄雄性比格犬1只,截去右下肢股骨中段全层15 mm制成骨缺损模型后,放入动物专用Micro CT进行容积扫描,完成数据采集、转化及后期处理,将处理后的数据导入CeraFab 7500光固化3D打印机中。根据设定参数启动打印程序,形成复合光敏树脂初胚,并对其进一步脱脂烧结,然后采用浸涂法制备HA/ZrO₂梯度复合材料。运用扫描电镜、X射线衍射(XRD)和生物力学实验分析HA/ZrO₂梯度复合材料的性能。制备HA/ZrO₂梯度复合材料浸提液。培养小鼠成纤维细胞株L929,采用噻唑蓝(MTT)法检测HA/ZrO₂梯度复合材料对体外细胞增殖和毒性的影响。将16只比格犬随机分为4组,每组4只。A组:截取犬股骨中段15 mm后,不植入任何材料;B组、C组、D组分别截去股骨中段15、25、35 mm制成骨缺损模型,然后分别植入相应规格的HA/ZrO₂梯度复合材料。术后第2、4、8、12 周拍摄术肢股骨正侧位X片,观察植入材料与自身骨结合情况及周围骨痂生长情况。术后12 周处死实验动物,截取整段股骨,大体观察标本植入材料与周围骨生长状况;行Micro CT扫描,测定新生骨量,并对新生骨进行3D图像重建;对股骨标本进行极限抗压实验,测量极限抗压强度。结果 运用3D打印技术制备的HA/ZrO₂梯度复合材料扫描电镜显示表面光滑,结构均匀,断口表面层均匀过渡结合,没有明显界限,相互之间冶金结合,结构稳定。XRD分析显示HA及ZrO₂峰形明显、结晶程度较好、粉体纯度高。抗压试验显示极限抗压强度为(43.37±2.31) MPa。MTT试验显示HA/ZrO₂梯度复合材料无明显细胞毒性。实验动物术后X线片显示:A组术后形成骨不连;B组有连续性骨痂通过,人工假体与宿主骨之间的界线消失;C组术后第2、4、8周连续性骨痂及新生骨长入速度较B组缓慢,但人工假体与断端间隙逐渐被新生骨填充,有连续性骨痂通过;D组新骨生成缓慢,仅在断端周围出现新生骨。术后12周取材,Micro CT 3D重建及新生骨量检测,B、C、D组单位体积新生骨量分别为(238.55±19.11) mm³/cm³、(223.31±13.41) mm³/cm³、(110.83±6.48) mm³/cm³,3组间比较差异有统计学意义(F=156.824,P＜0.01),其中B、C组新生骨量明显多于D组,差异均有统计学意义(P值均＜0.05)。新生骨CT 3D重建显示:B组复合材料整体被新生骨包绕,无外露;C组复合材料少许外露,表面基本被新生骨填塞;D组复合材料大部外露,新生骨散在长入。B、C、D组股骨标本极限抗压强度分别为(49.72±2.33) MPa、(49.81±2.43) MPa、(46.92±3.61) MPa,3组间比较差异无统计学意义(F=1.119,P＞0.05)。结论 运用3D打印技术制备的纳米HA/ZrO₂梯度复合材料具有可靠的生物相容性及生物力学强度,可以实现临床个体化治疗原则,能很好地修复犬股骨干35 mm内骨缺损,是一种理想的骨组织替换材料。     

Increased osteoblast adhesion on nanoparticulate calcium phosphates with higher Ca/P ratios

The biological properties of calcium phosphate-derived materials are strongly influenced by changes in Ca/P stoichiometry and grain size, which have not yet been fully elucidated to date. For this reason, the objective of this in vitro study was to understand osteoblast (bone forming cells) adhesion on nanoparticulate calcium phosphates of various Ca/P ratios. A group of calcium phosphates with Ca/P ratios between 0.5 and 2.5 were obtained by adjusting the Ca/P stoichiometry of the initial reactants necessary for calcium phosphate precipitation. For samples with 0.5 and 0.75 Ca/P ratios, tricalcium phosphate (TCP) and Ca(2)P(2)O(7) phases were observed. In contrast, for samples with 1.0 and 1.33 Ca/P ratios, the only stable phase was TCP. For samples with 1.5 Ca/P ratios, the TCP phase was dominant, however, small amounts of the hydroxyapatite (HA) phase started to appear. For samples with 1.6 Ca/P ratios, the HA phase was dominant. Last, for samples with 2.0 and 2.5 Ca/P ratios, the CaO phase started to appear in the HA phase, which was the dominant phase. Moreover, the average nanometer grain size, porosity (%), and the average pore size decreased in general with increasing Ca/P ratios. Most importantly, results demonstrated increased osteoblast adhesion on calcium phosphates with higher Ca/P ratios (up to 2.5). In this manner, this study provided evidence that Ca/P ratios should be maximized (up to 2.5) in nanoparticulate calcium phosphate formulations to increase osteoblast adhesion, a necessary step for subsequent osteoblast functions such as new bone deposition.     

骨形态发生蛋白载体材料的研究和应用现状

骨形态发生蛋白用于骨缺损的修复需要有合适的载体 ,目前已经有多种材料用作 BMP的载体 ,包括生物陶瓷、骨水泥、高分子多聚体、胶原、纤维蛋白凝块、异体骨、异种骨等。这些材料理化性能和生物学性能各不相同 ,因而与 BMP复合后也各具特色。本文介绍了不同载体与 BMP复合成人体骨的各自性能特点 ,并回顾了各种载体材料的研究和实际应用现状     

硅胶膜管联合BMP／HA修复大块骨缺损实验研究

目的：探讨硅胶膜（SGM）管与骨形态发生蛋白（BMP）和羟基磷灰石（HA）复合的修复兔长骨缺损的效果。方法：制备兔桡骨中段1．2cm缺损模型,实验组缺损区外围包绕硅胶膜,其内分别填充自体骨,BMP／HA,HA三种材料：对照组仅填充HA;空白组骨缺损区未填充,通过X线摄片,光学显微镜,立体计量学分析和生物力学评价对骨缺损区愈合效果进行.分析。结果：术后1个月,SGM＋BMP／HA组骨缺损区见有大量的类骨质,明显优于其他组,第2个月,SGM＋自体骨组与SGM＋BMP／HA组植入区有大片新骨形成,术后3个月,SGM＋自体骨级瑟SGM＋BMP／HA组骨缺损基本修复并出现骨组织改建现象,此时,SGM＋HA组与对照组骨缺损区也有少量新骨形成,空白缺损区为纤维组织充填,结论：硅胶膜管与自体骨或BMP／HA联合用于修复骨缺损成骨效果更佳,因为硅胶膜的屏障作用可使骨缺损区受到引导成骨和放导成骨的双重作用。     

HA/β-TCP支架材料的研究进展

随着骨修复材料需求的增多,HA/β-TCP复合支架作为一种兼具良好的生物相容性、生物降解性、骨传导性以及骨诱导性的生物材料受到了人们的广泛关注。本文关注于web of science上的相关文献,主要论述以下几个方面内容:HA/β-TCP组成比例对复合支架的性能影响;HA/β-TCP复合支架与其他主流材料的复合;新制作工艺的出现与结构改进。在技术推进和研究深入的背景下,对作为骨修复工程中较为理想的生物材料HA/β-TCP复合支架的发展现状进行介绍。     

Cem-OsteticTM人工骨浆复合骨形态发生蛋白对山羊椎体骨缺损修复作用研究*

目的 观察人工骨浆复合骨形态发生蛋白（BMP）对成年山羊椎体骨缺损的修复作用,并探讨其临床应用的可行性。方法将健康成年山羊24只随即分成单纯Cem-Ostefic^TM人工骨浆组（A组）和Cem-OsteticrM／BMP人工骨浆复合骨形态发生蛋白组（B组）,每组12只动物。在山羊胸腰段3处不相邻椎体分别建立椎体压缩性骨折撑开复位后骨缺损模型。将Cem-Ostetic^TM/BMP人工骨浆复合材料填充于缺损处,同时设立单纯人工骨浆对照组。术后4周、8周、12周分别处死动物,每组每次处死4只。通过大体观察,影像学检查,HE染色和生物力学测试。结果术后4周及8周时B组成骨情况、材料降解速度及生物力学强度和刚度测试明显优于A组（P〈0．05）,但仍未达到正常椎体的力学性能,差异有显著性（P〈0．01）。第12周时,两组X线及CT下均可见大量新骨生成,基本完整填充空隙,填充材料均基本完全降解,生物力学测试两组强度和刚度无显著性差异,基本达到了正常椎体的力学性能。结论Cem-Ostetic^TM人工骨浆是BMP的良好载体,Cem—Ostetic^TM／BMP复合材料具有较强的传导成骨和诱导成骨活性,生成的新骨有良好的强度和刚度。     

聚羟基丁酸-羟基戊酸共聚酯膜与聚羟基丁酸-羟基戊酸共聚酯-溶胶-凝胶生物活性玻璃复合材料修复骨缺损的研究

目的 探讨聚羟基丁酸-羟基戊酸共聚酯(PHBV)膜与PHBV-溶胶-凝胶生物活性玻璃(PHBV-SGBG)多孔复合材料促进骨再生的能力.方法 制备犬胫骨骨缺损模型,实验分4组:PHBV膜+PHBV-SGBG组;PHBV膜组;PHBV-SGBG组;空白对照组.术后2、4、8、12周取材,扫描电镜下观察各组骨缺损区的骨生长情况,并进行新骨的Ca、P元素微区定量测定.结果 所有植入材料组(PHBV膜+PHBV-SGBG组、PHBV膜组、PHBV-SGBG组)均可不同程度地促进新骨的形成.术后12周,PHBV膜+PHBV-SGBG组骨缺损区的修复重建基本完成,新生骨的Ca/P比值(1.625±0.037)与周围正常骨的Ca/P比值(1.625±0.063)差异无统计学意义(P＞0.05);空白对照组的新生骨质疏松有洞,显示有较高的有机组织能谱;PHBV-SGBG组的骨修复略优于PHBV膜组,但两组间的差异无统计学意义(P＞0.05).结论 PHBV膜具有引导骨再生的能力,PHBV-SGBG复合材料具有很好的骨传导性和骨形成能力,联合应用PHBV膜和PHBV-SGBG复合材料具有促进骨缺损修复的协同作用.     

Expression of core binding factor 1 and osteoblastic markers in C2C12 cells induced by calcium phosphate ceramics in vitro

The in vivo osteoinductive capacity of porous calcium phosphate ceramics (Ca/P ceramics) with special structure and phase composition had been found for almost decades. The mechanism of the osteoinductivity of porous calcium phosphate is studied by C2C12 cells culture in this paper. C2C12 cells were cocultured with four kinds of porous Ca/P ceramics for 2 and 5 days, without adding other growth factors. The four kinds of Ca/P ceramics were pure HA sintered at 1250 degrees C and HA/TCP with a ratio of 60/40 sintered at 1100, 1200, and 1250 degrees C respectively. RT-PCR analysis found that the Ca/P ceramics induced the expression of Cbfa1, collagen type I, bone sialoprotein, and osteocalcin in C2C12 cells, while they did not induce mRNA expression of Indian hedgehog (IHH) that regulate chondrocyte differentiation. Our results showed that Ca/P ceramics alone were sufficient to induce C2C12 cells differentiation. The induction of bone-related markers expression by Ca/P ceramics in osteoprogenitor cells suggested that the osteogenesis induced by the ceramics was intramembranous and the osteoinductivity was their intrinsic property.     

Surface reactions of calcium phosphate ceramics to various solutions

The surface reactions of calcium phosphate ceramics have been thought to play an important role in bonding with living bone. Hydroxyapatite (HA), tricalcium phosphate (TCP), and two kinds of apatite-containing glass ceramics were immersed in three types of solutions with different chemical constituents. The first solution was a physiological saline, the second contained phosphate (PO4), and the third was a balanced salt solution consisting of calcium (Ca), magnesium (Mg), and PO4. After serial incubation periods, changes in the solutions were assessed by measurement of total Ca, Mg, and PO4. The ceramic surfaces were studied using scanning electron spectroscopy, infrared reflection spectroscopy, and thin-film x-ray diffraction. The surface reactions of the ceramics were greatly affected by the chemical compositions of the surrounding media. In the complete solution with both Ca and PO4, a carbonated apatite layer was formed on the surfaces of HA, TCP, and the glass ceramics. In comparison to HA and TCP, the glass ceramics were characterized as Ca-releasing materials, the dissolved Ca creating an apatite layer on the surfaces in a few days, in conjunction with PO4 stock in the surrounding media. The immersion test with various solutions proved to be a simple and effective method of assessing surface conditions of ceramic materials.     

体内组织工程骨的BMP4 mRNA表达

比较磷酸钙陶瓷构建的体内组织工程骨和自然再生骨的BMP4 mRNA表达.制备Φ5 mm×8 mm的骨诱导性磷酸钙陶瓷20粒并分别植入5只狗的竖直肌内,同时,拔除狗的一颗磨牙形成自然再生骨模型.术后1、2、4、12及24周,取出体内组织工程骨及自然再生骨.提取总 RNA, 经逆转录成 cDNA 后,用实时相对定量PCR的方法检测 BMP4 mRNA 的表达.结果表明:在本实验周期,BMP4 mRNA 在磷酸钙陶瓷构建的体内组织工程骨中的表达量高于在自然再生骨中的表达量,但BMP4 mRNA 在体内组织工程骨和自然再生骨中有相同的基因表达时序性.作为类似自体骨的骨替代物,磷酸钙陶瓷构建的体内组织工程骨具有切实可行的应用前景.     

羟基磷灰石+骨形成蛋白+纤维蛋白粘合剂复合物增高牙槽嵴的新骨形成反应

目的:观察羟基磷灰石+骨形成蛋白+纤维蛋白粘合剂(HA+BMP+FS)复合物增高牙槽嵴的新骨形成反应。方法:从小牛长骨中提取骨形成蛋白(BMP),首次采用羟基磷灰石(HA)与纤维蛋白粘合剂(FS)以及具有高效骨诱导性的BMP三者复合,形成一种功能互补的新的人工骨材料,用以进行增高犬的无牙颌牙槽嵴,术后3、6、12、24周动物处死取标本作大体、组织学观察、组织学新骨形成量计算、四环素荧光标记显微法、扫描电镜形貌观察、背反射电子图象和X线能谱分析法等检查。结果:发现:(1)实验组术后3周起出现编织骨,6周新骨增加,12~24周有成熟的骨组织相互连结,布满HA微粒间隙。对照组术后3周未见新骨,6周个别HA微粒与基骨接触,12~24周少许新骨长入。(2)新骨组织与HA直接结合,钙磷元素与HA和基骨接近。结论:HA+BMP+FS复合材料可显著地促进HA-基骨界面骨性结合,加快再建牙槽嵴的新骨形成,增加新骨形成量,从形态和功能上大大提高再建牙槽嵴的质量。     

骨髓间充质干细胞复合羟基磷灰石/磷酸三钙植骨材料的体外研究

目的研究兔骨髓间充质干细胞(BMSCs)在羟基磷灰石/磷酸三钙(HA/TCP)植骨材料上的黏附增殖情况。方法抽取兔股骨骨髓,进行贴壁培养BMSCs。在成骨诱导液中诱导BMSCs,于7d用钙钴法检测碱性磷酸酶活性,10d进行茜素红矿化结节染色;在成脂诱导液中诱导BMSCs,于21d进行油红O染色。将BMSCs接种到HA/TCP植骨材料上,加入成骨诱导液,采用倒置显微镜、荧光显微镜及扫描电镜检测,并采用四氮唑蓝(MTT)比色法测定HA/TCP植骨材料上BMSCs的增殖情况。结果BMSCs在成骨诱导液中7d碱性磷酸酶呈强阳性,10d矿化结节染色呈橘红色;在成脂诱导液中,21d油红O染色呈阳性。BMSCs在HA/TCP植骨材料上孔隙周围及孔隙内生长良好并大量增殖。MTT分析结果显示,HA/TCP对BMSCs的体外增殖无抑制作用。结论BMSCs与HA/TCP植骨材料有良好的生物相容性。     

Differential osteogenic activity of osteoprogenitor cells on HA and TCP/HA scaffold of tissue engineered bone

Biomaterial, an essential component of tissue engineering, serves as a scaffold for cell attachment, proliferation, and differentiation; provides the three dimensional (3D) structure and, in some applications, the mechanical strength required for the engineered tissue. Both synthetic and naturally occurring calcium phosphate based biomaterial have been used as bone fillers or bone extenders in orthopedic and reconstructive surgeries. This study aims to evaluate two popular calcium phosphate based biomaterial i.e., hydroxyapatite (HA) and tricalcium phosphate/hydroxyapatite (TCP/HA) granules as scaffold materials in bone tissue engineering. In our strategy for constructing tissue engineered bone, human osteoprogenitor cells derived from periosteum were incorporated with human plasma-derived fibrin and seeded onto HA or TCP/HA forming 3D tissue constructs and further maintained in osteogenic medium for 4 weeks to induce osteogenic differentiation. Constructs were subsequently implanted intramuscularly in nude mice for 8 weeks after which mice were euthanized and constructs harvested for evaluation. The differential cell response to the biomaterial (HA or TCP/HA) adopted as scaffold was illustrated by the histology of undecalcified constructs and evaluation using SEM and TEM. Both HA and TCP/HA constructs showed evidence of cell proliferation, calcium deposition, and collagen bundle formation albeit lesser in the former. Our findings demonstrated that TCP/HA is superior between the two in early bone formation and hence is the scaffold material of choice in bone tissue engineering.     

Enhancement of the in vivo osteogenic potential of marrow/hydroxyapatite composites by bovine bone morphogenetic protein

A composite of marrow mesenchymal stem cells and porous hydroxyapatite (HA) has in vivo osteogenic potential. To investigate factors enhancing the osteogenic potential of marrow/HA composites, we prepared a bone morphogenetic protein (BMP) fraction from the 4M guanidine extract of bovine bone by heparin-sepharose affinity chromatography. Marrow/HA composites or composites containing marrow mesenchymal stem cells, BMP, and HA (marrow/BMP/HA composites) were implanted subcutaneously in 7-week-old male Fischer rats. BMP/HA composites and HA alone were also implanted. The implants were harvested after 2, 4, or 8 weeks and were prepared for histological and biochemical studies. Histological examination showed obvious de novo bone formation together with active osteoblasts at 2 weeks, as well as more extensive bone formation at 4 and 8 weeks in many pores of the marrow/BMP/HA composites. The marrow/HA composites did not induce bone formation at 2 weeks, but there was moderate bone formation at 4 weeks. At 2 weeks, only marrow/BMP/HA composites resulted in intensive osteogenic activity, judging from alkaline phosphatase and osteocalcin expression at both the protein and gene levels. These results indicate that the combination of marrow mesenchymal stem cells, porous HA, and BMP synergistically enhances osteogenic potential, and may provide a rational basis for their clinical application, although further in vivo experiment is needed.     

玉米蛋白3-D多孔支架材料仿生矿化的初步研究

为了提高玉米蛋白的骨诱导性和骨结合性,以促进其在骨组织工程领域中的应用,将玉米蛋白多孔支架材料浸泡于5倍模拟体液(5×SBF)中,尝试在不同的条件下对玉米蛋白多孔支架材料表面进行仿生矿化。通过场发射扫描电镜(SEM)观察仿生矿化后多孔支架材料各个表面的形貌,能谱(EDS)计算出钙磷比(Ca/P)比。在5倍模拟体液中浸泡后,材料各表面均形成了分布和尺寸相对均匀的微米级(2~10 um)颗粒。其钙磷比接近羟基磷灰石,可以认为获得了比较理想的玉米蛋白-羟基磷灰石多孔支架复合材料。