不同来源骨髓间充质干细胞的体内成软骨

背景：骨髓间充质干细胞经体外诱导后可修复软骨缺损,但目前采用的种子细胞多来源于自体或同种异体。 目的：观察同种异体及异种来源的骨髓间充质干细胞诱导成软骨后修复喉软骨缺损的效果。 方法：分别取人胚胎骨髓间充质干细胞和刚出生兔骨髓间充质干细胞的第3代细胞种植于聚乳酸-羟基乙酸共聚物生物支架上,并加入转化生长因子β1和软骨形态发生蛋白诱导成软骨细胞。将两种细胞体系植入新西兰白兔体内,并于植入后4,8周取材行大体、组织学观察。 结果与结论：植入后4,8周人胚胎骨髓间充质干细胞和兔骨髓间充质干细胞均有新生组织填充,经组织学观察大部分为软骨细胞,分泌软骨细胞基质糖胺聚糖和Ⅱ型胶原,且两种细胞支架复合物所生成的软骨细胞数大致相同,并无明显的免疫排斥反应。提示异种来源的骨髓间充质干细胞复合聚乳酸-羟基乙酸共聚物在转化生长因子β1和软骨形态发生蛋白联合诱导下所得的组织工程化软骨,与同种来源的骨髓间充质干细胞所获得的组织工程化软骨修复喉软骨缺损具有可比性。     

SOX-9转染骨髓基质细胞与聚乳酸-羟基乙酸共聚物的生物相容性

背景:Sox基因家族是一个新发现的基因家族,在胚胎发育、性别分化、神经系统及骨骼系统发育过程中起着重要的作用。目的:观察SOX-9基因转染骨髓基质干细胞后在聚乳酸-羟基乙酸共聚物培养生长的生物相容性,以及其复合材料修复软骨缺损动物模型的可行性。方法:将SOX-9基因转染成功后的骨髓基质细胞在聚乳酸-羟基乙酸共聚物培养生长,制备软骨缺损动物模型,将复合物植入软骨缺损,通过大体标本观察、组织学观察及Ⅱ型胶原免疫组织化学及RT-PCR检测对软骨缺损模型的修复效果。结果与结论:SOX-9基因转染骨髓基质干细胞后可以在聚乳酸-羟基乙酸共聚物上正常生长,并有Ⅱ型胶原的高表达,将复合物植入软骨缺损后,可以修复软骨缺损动物模型。聚乳酸-羟基乙酸共聚物与转染后的骨髓基质细胞具有良好的生物相容性,可以修复兔软骨缺损动物模型。     

无纺网与多孔海绵状材料作为软骨组织工程支架的适用性及体内降解性

背景：聚羟基乙酸无纺网与聚羟基丁酸酯-聚羟基己酸酯共聚物多孔海绵具有良好的塑形适应性、生物降解性与生物相容性。 目的：观察聚羟基乙酸无纺网与聚羟基丁酸酯-聚羟基己酸酯共聚物多孔海绵作为软骨组织工程支架的适用性及体内降解性。 方法：分别制备乳兔软骨细胞-聚羟基乙酸无纺网复合物、乳兔软骨细胞-聚羟基丁酸酯-聚羟基己酸酯共聚物多孔海绵复合物。在实验组成年兔两侧背部皮下分别植入制备的两种复合物,在对照组成年兔两侧背部皮下分别植入聚羟基乙酸无纺网与聚羟基丁酸酯-聚羟基己酸酯共聚物。 结果与结论：组织学观察显示,以聚羟基乙酸无纺网获取的组织工程软骨,植入4 周时软骨细胞较小,软骨内有较多聚羟基乙酸纤维残留,8周时软骨细胞较成熟,包埋在陷窝内,聚羟基乙酸纤维消失,12周时软骨细胞成熟,基质分泌丰富,无聚羟基乙酸存留;以聚羟基丁酸酯-聚羟基己酸酯共聚物多孔海绵获取的组织工程软骨,植入4周时软骨细胞不成熟,软骨基质内似“杂质”样材料残留物较多,8周时软骨细胞较成熟,软骨基质内仍可见材料残留,12周时软骨基质材料残留基本消失。两组组织工程软骨特殊染色与免疫组织化学检测均显示再生软骨胶原与基质黏多糖生成良好,软骨中均检测出Ⅱ型胶原。表明两种材料作为软骨组织工程支架具有良好的适用性,其降解时间均达到组织工程软骨构建的要求。中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程全文链接：     

丝素蛋白/羟基磷灰石材料复合骨髓间充质干细胞构建组织工程化软骨

背景：随着组织工程的兴起,软骨损伤的修复可能性显著地提高,但单一的支架材料均不能符合理想支架,有一定的局限性。 目的：观察骨髓间充质干细胞复合丝素蛋白/羟基磷灰石构建组织工程化软骨的可行性。 方法：体外分离培养骨髓间充质干细胞,并定向诱导成软骨细胞,与丝素蛋白/羟基磷灰石复合培养,构建膝关节胫骨平台全层关节软骨缺损。54只大白兔单侧膝关节全层软骨缺损模型后随机抽签法分为3组,复合组植入细胞-丝素蛋白/羟基磷灰石复合物;材料组植入单纯丝素蛋白/羟基磷灰石,对照组不行任何植入。植入后8,12周CT检查及组织学检查观察软骨缺损修复情况。 结果与结论：植入后8周,复合组关节面不平整,关节间隙增大,形成新生类软骨细胞,基质丰富。材料组关节面塌陷,软骨细胞少量增殖。植入后12周,复合组关节面平整,关节间隙如常。大量软骨细胞出现,与周边软骨色泽一样,支架材料完全降解。材料组关节面不平整,软骨细胞不完全充填,支架材料部分降解。对照组未见修复。提示用骨髓间充质干细胞复合丝素蛋白/羟基磷灰石可形成透明软骨修复动物膝关节全层软骨缺损,显示了丝素蛋白/羟基磷灰石材料作为关节软骨组织工程支架材料的良好生物相容性。     

聚羟基烷酸酯聚合物负载软骨细胞修复同种异体喉软骨缺损

背景：喉软骨组织缺损发病率较高,患者发病后主要以疼痛、肿胀、功能障碍等为主。目前,临床上对于喉软骨组织损伤更多的以修复手术治疗为主,常规材料虽然能够有效的改善患者症状,但是长期疗效欠佳。近年来,软骨组织工程在临床上研究相对较多,但是在耳鼻咽喉科实际使用相对较多。目的：探讨聚羟基烷酸酯聚合物负载软骨细胞在同种异体喉软骨缺损修复中的效果。方法：将聚羟基丁酸酯与聚羟基己酸酯共聚物材料设为细胞外基质,采用组织工程技术制备细胞-材料复合物,将初级组织工程软骨组织直接移植于兔甲状软骨缺损的修复,或将初级组织工程软骨组织体内植入一定时期形成较成熟组织工程软骨再应用于甲状软骨缺损的修复。实验设单纯聚羟基丁酸酯与聚羟基己酸酯共聚物材料修复组和单纯软骨细胞修复组进行对照,对甲状软骨缺损修复效果进行大体和组织学评价。结果与结论：初级组软骨在电镜扫描下能够看见软骨细胞表现为串珠状,培养4周后能够看见大量胶冻形状的基质。在电子显微镜下进行观察结果显示：细胞分布在复合材料表面和海绵状空隙中,显示多个类圆形小突起;入选新西兰兔均取得手术成功,并且手术后并未出现呼吸困难、进食困难等现象;实验初级组织工程软骨组1只兔出现短暂喘鸣;实验较成熟组织工程软骨组1只动物术后2周死于腹泻。大体测试负载软骨细胞的聚羟基丁酸酯与聚羟基己酸酯共聚物有一定硬度。皮下植入4周后成熟细胞表现为白色片状,材料具有弹性。植入后4,8周两组修复区与原有软骨间光滑平淡,但是修复区域则色发黄。单纯聚羟基丁酸酯与聚羟基己酸酯共聚物材料修复组和单纯软骨细胞修复组修复区均凹陷,仅见结缔组织。实验组兔不良反应发生率显著低于对照组(P < 0.05)。结果证实,聚羟基烷酸酯聚合物负载软骨细胞移植修复同种异体喉软骨缺损效果较好。中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

聚羟基烷酸酯聚合物负载软骨细胞修复同种异体喉软骨缺损

背景：软骨组织工程基础研究相当深入,但在耳鼻咽喉科实际应用研究颇少,探索组织工程技术简便实用的喉软骨修复方法是值得研究的课题。 目的：比较多孔海绵状聚羟基丁酸酯与聚羟基己酸酯共聚物生物材料负载软骨细胞体外培养形成的初期组织工程软骨组织与体内植入一定时期形成的较成熟组织工程软骨组织修复同种异体甲状软骨缺损的效果。 方法：收集体外培养第3代乳兔(3 d龄)软骨细胞,以多孔海绵状聚羟基丁酸酯与聚羟基己酸酯共聚物生物材料为细胞外基质,采用组织工程技术制备细胞-材料复合物,共同体外培养形成初级组织工程软骨组织后直接应用于成兔甲状软骨缺损的修复(实验组A,n=5)或将初级组织工程软骨组织体内植入一定时期形成较成熟组织工程软骨再应用于甲状软骨缺损的修复(实验组B,n=5)。设单纯聚羟基丁酸酯与聚羟基己酸酯共聚物材料修复组(对照A组,n=4)和单纯软骨细胞修复组(对照B组,n=4)作为对照。分别于术后4周(实验B组)和8周(实验A组、对照A组、对照B组)取材,对甲状软骨缺损修复效果进行大体和组织学评价。 结果与结论：两者大体支架形态基本一致,修复区与原有软骨均相续平坦,无凹陷及缺损。但实验A组存在界面无细胞区,修复区基质分泌不丰富;实验B组界面区有细胞生长,基质分泌良好。两者炎细胞浸润均不明显。对照组修复区凹陷,呈暗红色软组织充填,组织学及特殊染色检查未发现软骨样结构及其分泌的基质成分。结果表明在有免疫力的动物体内,初级组织工程软骨组织直接应用与体内植入后再应用均能有效修复同种异体甲状软骨缺损,无明显免疫反应;相同时期内,应用较成熟组织工程软骨组织修复效果优于应用初级组织工程软骨组织。然而,直接应用初级组织工程软骨组织可节省时间、成本、工作量及操作环节,避免二次皮下手术的痛苦,是比较实用的方法之一。     

改性纳米羟基磷灰石/聚乳酸-聚羟乙酸复合骨髓基质干细胞修复兔桡骨缺损*

背景：前期试验证实骨髓基质干细胞能够在改性纳米羟基磷灰石/聚乳酸-聚羟乙酸材料表面黏附、增殖,该材料具有良好的生物安全性。 目的：观察骨髓基质干细胞与改性纳米羟基磷灰石/聚乳酸-聚羟乙酸材料复合修复兔桡骨缺损的效果。 方法：建立兔15 mm桡骨缺损模型,随机分为3组：空白对照组不进行任何处理,实验组植入改性纳米羟基磷灰石/聚乳酸-聚羟乙酸+骨髓基质干细胞组织工程化骨,对照组植入单纯改性纳米羟基磷灰石/聚乳酸-聚羟乙酸支架材料。 结果与结论：①X射线评价：术后1~12周,实验组骨缺损修复程度及速度明显优于空白对照组与对照组(P < 0.05)。②组织学检测：实验组术后4周即可观察到新生骨和纤维组织长入材料空隙,局部形成陷窝结构;8周时新生骨组织增多,部分可观察到成熟的骨小梁结构;12周时可见大量成熟骨细胞,骨小梁排列紧密,移植材料逐步被新生骨取代,与正常骨组织形态基本一致,且骨小梁出现时间早于空白对照组与对照组。说明骨髓基质干细胞复合改性纳米羟基磷灰石/聚乳酸-聚羟乙酸构建的组织工程化骨能够促进骨缺损处新骨的生成,较单纯支架材料具有明显优势。     

改良纤维蛋白胶软骨细胞复合物修复软骨缺损的实验研究

目的：研究改良纤维蛋白胶细胞复合物和标准纤维蛋白胶细胞复合物修复关节软骨缺损的效果。方法：(1)分离3周龄幼兔关节软骨细胞并体外单层培养，将抑肽酶和氨甲环酸加入纤维蛋白胶(FG)中，构建标准FG细胞复合物和改良FG细胞复合物。(2)体外培养后植入动物模型体内，A，B组缺损内分别植入标准FG细胞复合物和改良FG细胞复合物，C组为空白对照。术后分期取材，对新生软骨进行组织学观察及氨基多糖含量测定。结果：改良FG细胞组新生软骨在组织学特性上与正常软骨相似，修复效果优于标准组。结论：在纤维蛋白胶中加入抑肽酶和氨甲环酸，可使FG降解速度与软骨细胞基质形成速度同步，提高了软骨修复质量。     

Ⅰ/Ⅲ型胶原膜联合自体骨髓间充质干细胞修复兔膝关节软骨缺损

背景：研究表明Ⅰ型胶原和Ⅲ型胶原都有利于骨髓间充质干细胞的黏附、增殖和分化。 目的：观察Ⅰ/Ⅲ型胶原膜联合自体骨髓间充质干细胞修复兔膝关节软骨缺损的可行性。 方法：取24只新西兰大白兔制作双膝股骨滑车直径3.8 mm、深2 mm关节软骨缺损模型,分为2组：实验组缺损区植入Ⅰ/Ⅲ型胶原膜-自体骨髓间充质干细胞复合物,对照组缺损区植入单纯Ⅰ/Ⅲ型胶原膜。 结果与结论：膝关节股骨标本组织学染色显示,实验组植入8周时为类透明软骨修复,12周时接近于正常软骨;对照组植入8周时以纤维样组织修复为主,12周时为纤维软骨修复。实验组植入后8,12周组织学评分均明显高于对照组(P < 0.001)。表明运用Ⅰ/Ⅲ型胶原膜-自体骨髓间充质干细胞复合物可修复关节软骨缺损。     

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。     

点种法移植软骨细胞修复关节软骨缺损

背景：生物性的重建虽能达到修复缺损,重建关节面的目的,但功能上难以与正常软骨一致。应用可降解的聚合物把移植的软骨细胞包埋起来进行移植,可能获得真正意义上的透明软骨。 目的：观察以同种异体兔软骨细胞胶原包埋后,点种法移植软骨细胞修复关节软骨缺损的效果。 方法：新西兰纯种兔制备膝关节全层软骨缺损后分为3组：分别进行胶原包埋软骨细胞点种法移植、单纯软骨细胞点种法移植和仅在大面积软骨缺损的软骨下钻孔。 结果与结论：术后2,4,12,24周观察组织学动态变化,发现胶原包埋软骨细胞点种法移植组能获得透明软骨修复,而软骨细胞点种法组和单纯软骨下骨钻孔组缺损区仅为纤维组织填充,并且胶原包埋软骨细胞点种法移植组兔各期平均组织学和组织化学得分均高于其他两组(P < 0.01)。说明胶原包埋点种法软骨细胞移植能获得透明软骨修复,尤其适用于大面积软骨缺损。     

透明质酸钠复合外周血间充质干细胞修复软骨缺损

背景：近几年外周血来源的间充质干细胞被重视,但并未见应用其修复软骨缺损的报道。 目的：将动员后外周血来源的间充质干细胞与透明质酸钠复合后注入关节腔内,探讨修复关节软骨缺损的可行性。 方法：联合应用干细胞因子及粒细胞集落刺激因子动员2月龄兔,取外周血后分离间充质干细胞,进行原代及传代细胞培养。以透明质酸钠为细胞载体材料,将它与第3代间充质干细胞混合制成细胞混悬液。于3月龄兔双膝关节股骨内外髁负重区制造软骨缺损区,随机选取10只以左膝为实验组,术后1周关节腔内注射含透明质酸钠的细胞悬液0.5 mL,右膝为透明质酸钠对照组,注射透明质酸钠0.5 mL,其余5只作为生理盐水对照组,每周1次,连续3次。治疗后12周时处死取材,观察缺损处修复情况、新生组织类型及有无免疫反应。 结果与结论：①兔外周血中分离培养的间充质干细胞与骨髓来源的形态相似,能够进行原代培养。②膝关节内注射外周血间充质干细胞与透明质酸钠的混悬液后未见红肿等现象发生,关节活动良好。③治疗后12周时,实验组部分缺损区基本被软骨样组织填满,表面较平整光滑。但部分边界尚可见,浅层纤维化较明显。实验组的修复效果明显优于透明质酸钠对照组及生理盐水对照组。说明动员后外周血间充质干细胞与透明质酸钠的混悬液短期内对关节软骨缺损具有一定的修复作用。     

Tissue engineering of articular cartilage with autologous cultured adipose tissue-derived stromal cells using atelocollagen honeycomb-shaped scaffold with a membrane sealing in rabbits

Adipose tissue derived stromal cells (ATSCs), which were isolated from adipose tissue of rabbit, have shown to possess multipotential, that is, they differentiate into osteoblasts and adipocytes in plate-culturing and into chondrocytes in an established aggregate culture using defined differentiation-inductive medium. The aim of this study was to evaluate the utility of ATSCs in tissue engineering procedures for repair of articular cartilage-defects using the atelocollagen honeycomb-shaped scaffold with a membrane sealing (ACHMS-scaffold). We intended to repair full-thickness articular cartilage defects in rabbit knees using autologously cultured ATSCs embedded in the ACHMS-scaffold. ATSCs were incubated within the ACHMS-scaffold to allow a high density and three-dimensional culture with control medium. An articular cartilage defect was created on the patellar groove of the femur, and the defect was filled with the ATSCs-containing ACHMS-scaffold, ACHMS-scaffold alone, or empty (control). Twelve weeks after the operation, the histological analyses showed that only the defects treated with the ATSCs-containing ACHMS-scaffold were filled with reparative hyaline cartilage, highly expressed Type II collagen. These results indicate that transplantation of autologous ATSCs-containing ACHMS-scaffold is effective in repairing articular cartilage defects.     

组织工程化软骨细胞和骨髓间充质干细胞用于修复同种异体关节软骨缺损

背景：关节软骨几乎没有自身修复的能力,目前临床大多采用自体或异体软骨移植修复、软骨膜或骨膜移植修复、软骨细胞移植修复。由于自体软骨来源有限,异体软骨又存在慢性免疫排斥反应,最终可能导致预后不佳;软骨膜或骨膜移植修复的软骨易于退化,导致修复效果不佳。 目的：总结组织工程化软骨细胞、骨髓间充质干细胞及两者共培养对同种异体软骨缺损修复作用的研究现状。 方法：应用计算机检索PubMed 数据库及中国期刊网全文数据库1994-01/2012-01有关组织工程化软骨细胞和骨髓间充质干细胞用于修复同种异体关节软骨缺损方面的文章,英文检索词为“cartilage defect,allograft,chondrocyte,mesenchymal stem cells,bone marrow mesenchymal stem cells”,中文检索词为“软骨缺损,同种异体移植,软骨细胞,骨髓间充质干细胞”。排除重复性及非中英文语种研究,共保留35篇文献进行综述。 结果与结论：随着体外细胞培养方法的不断改进,现已能够把软骨细胞从坚韧的软骨中分离出来,并获得大量高纯度的软骨细胞并繁殖出新生软骨细胞。软骨细胞培养增殖能力低,传代培养容易引起老化和去分化;而成体骨髓中骨髓间充质干细胞含量少,随传代次数的增多成软骨潜能明显降低。骨髓间充质干细胞和软骨细胞共培养,两种细胞相互促进增殖和分化,作为种子细胞可减少软骨细胞增殖传代次数并节省软骨细胞数量,与组织工程支架材料复合能有效修复关节软骨缺损。     

同种异体和异种来源骨髓间充质干细胞诱导成软骨修复喉软骨缺损

BACKGROUND: Because chondrocytes have no regeneration ability, to select suitable seed cells is the primary problem to repair cartilage defects. OBJECTIVE: To investigate the effect of allogeneic versus heterologous bone marrow mesenchymal stem cells (BMSCs) in repairing laryngeal cartilage defects after chondrogenic induction. METHODS: BMSCs from human and rabbits were isolated and cultured. Passage 3 cells were cultured in chondrogenic induction medium containing transforming transforming growth factor beta 1 and bone morphogenetic protein, and then were dropped onto a poly(lactic-co-glycolic acid) (PLGA) scaffold. Thirty New Zealand rabbits were randomly assigned into three groups: blank control group, human BMSCs group, rabbit BMSCs group. Animal models of laryngeal cartilage defects were made in the three groups. After modeling, saline-soaked PLGA scaffold, PLAG scaffold with human BMSCs or with rabbit BMSCs were implanted respectively into the rabbits in the normal blank, human BMSCs and rabbit BMSCs groups. The expression of type II collagen in the larynx and its surrounding tissues was detected by immunohistochemistry at 4 and 8 weeks postoperatively. RESULTS AND CONCLUSION: The animals in each group breathed normally with no presence of wheezing, and their eating and activity were good. Moreover, there was no purulency or infection in the three groups. At 4 and 8 weeks after operation, the positive rates of type II collagen in the two BMSCs groups were significantly higher than that in the blank control group (P < 0.05). There was no significant difference between two BMSCs groups (P > 0.05). These results show that both allogeneic and heterologous BMSCs have good therapeutic effects on the repair of laryngeal cartilage defects in rabbits.      

Repair of articular cartilage defect by cell transplantation

Full-thickness articular cartilage defects are a major clinical problem; however, at present there is no treatment that is widely accepted to regeneratively repair these lesions. The current therapeutic approach is to drill or abrade the base of the defect to expose the bone marrow with its cells and growth factors. This usually results in a repaired tissue of fibrocartilage that functions poorly in the loaded joint environment. Recently, autologous cultured chondrocyte transplantation and mosaic plasty were explored. We can repair small articular cartilage defects using these methods, although their effectiveness is still controversial. We have reported that transplantation of allogeneic chondrocytes embedded in collagen gels or allogeneic chondrocytes cultured in collagen gels could repair articular cartilage defect in a rabbit model. We also reported that autologous culture-expanded bone marrow mesenchymal cell transplantation could repair articular cartilage defect in a rabbit model. This procedure offers expedient clinical use, given that autologous bone marrow cells are easily obtained and can be culture-expanded. We transplanted autologous culture-expanded bone marrow cells into the cartilage defect of the osteoarthritic knee joint on 11 patients at the time of high tibial osteotomy. As early as 6.8 weeks after transplantation, the defect was covered with white soft tissue, in which slight metachromasia was histologically observed. Thirty-three weeks after transplantation, the repaired tissue had hardened. Histologically, repaired tissues showed stronger metachromasia and a partial hyaline cartilage-like appearance. This procedure may prove a promising method by which to repair articular cartilage defects.     

Repair of articular cartilage defects treated by microfracture and a three-dimensional collagen matrix

The objective of our study was to evaluate the behavior of ovine chondrocytes and bone marrow stromal cells (BMSC) on a matrix comprising type-I, -II, and -III collagen in vitro, and the healing of chondral defects in an ovine model treated with the matrix, either unseeded or seeded with autologous chondrocytes, combined with microfracture treatment. For in vitro investigation, ovine chondrocytes and BMSC were seeded on the matrix and cultured at different time points. Histological analysis, immunohistochemistry, biochemical assays for glycosaminoglycans, and real-time quantitative PCR for collagens were performed. The animal study described here included 22 chondral defects in 11 sheep, divided into four treatment groups. Group A: microfracture and collagen matrix seeded with chondrocytes; B: microfracture and unseeded matrices; C: microfracture; D: untreated defects. All animals were sacrificed 16 weeks after implantation, and a histomorphometrical and qualitative evaluation of the defects was performed. The in vitro investigation revealed viable cells up to 3 weeks; chondrocytes had a predominantly round morphology, produced glycosaminoglycans, and expressed both collagen markers, whereas BMSC stained positive for antibodies against type-II collagen; however, no mRNA for type-II collagen was amplified. All treatment groups of the animal model showed better defect filling compared to untreated knees. The cell-seeded group had the greatest quantity of repair tissue and the largest quantity of hyaline-like tissue. Although the collagen matrix is an adequate environment for BMSC in vitro, the additionally implanted unseeded collagen matrix did not increase the repair response after microfracture in chondral defects. Only the matrices seeded with autologous cells in combination with microfracture were able to facilitate the regeneration of hyaline-like cartilage.     

Tissue engineering of articular cartilage using an allograft of cultured chondrocytes in a membrane-sealed atelocollagen honeycomb-shaped scaffold (ACHMS scaffold)

The aim of this study was to investigate with tissue engineering procedures the possibility of using atelocollagen honeycomb-shaped scaffolds sealed with a membrane (ACHMS scaffold) for the culturing of chondrocytes to repair articular cartilage defects. Chondrocytes from the articular cartilage of Japanese white rabbits were cultured in ACHMS scaffolds to allow a high-density, three-dimensional culturing for up to 21 days. Although the DNA content in the scaffold increased at a lower rate than monolayer culturing, scanning electron microscopy data showed that the scaffold was filled with grown chondrocytes and their produced extracellular matrix after 21 days. In addition, glycosaminoglycan (GAG) accumulation in the scaffold culture was at a higher level than the monolayer culture. Cultured cartilage in vitro for 14 days showed enough elasticity and stiffness to be handled in vivo. An articular cartilage defect was initiated in the patellar groove of the femur of rabbits and was subsequently filled with the chondrocyte-cultured ACHMS scaffold, ACHMS scaffold alone, or non-filled (control). Three months after the operations, histological analysis showed that only defects inserted with chondrocytes being cultured in ACHMS scaffolds were filled with reparative hyaline cartilage, and thereby highly expressing type II collagen. These results indicate that implantation of allogenic chondrocytes cultured in ACHMS scaffolds may be effective in repairing articular cartilage defects.