利用脂肪干细胞构建软骨修复兔膝关节软骨缺损的初步研究

目的 利用兔同种异体软骨脱细胞基质支架和脂肪干细胞体外构建组织工程软骨,探讨其修复关节软骨损伤的可行性.方法 将新西兰大白兔的脂肪干细胞与软骨脱细胞基质支架复合,于软骨细胞方向诱导培养基中培养两周,构建组织工程软骨.兔24只随机分为A、B、C 3组, A组关节软骨缺损处置入经诱导的脂肪源干细胞复合软骨基质支架, B组缺损处只置入软骨基质支架, C组软骨缺损处不做任何处理.分别于术后第12周处死动物,修复处行大体、组织学、Ⅱ型胶原免疫组化染色和透射电镜检测.结果 A组软骨缺损处被类软骨组织填充,修复区表面光滑;Ⅱ型胶原免疫组化染色和甲苯胺蓝染色阳性;电镜下可见软骨陷窝内有细胞结构存在,且有大量均匀颗粒状细胞分泌基质成分存在,细胞周围大量胶原纤维.B组软骨缺损处为纤维组织状物填充,C组软骨缺损处无修复组织填充.结论 脂肪干细胞与软骨脱细胞基质复合并向软骨诱导后可良好地修复关节软骨缺损,具有替代正常软骨的潜力.     

补肾行气活血法在骨髓基质干细胞诱导软骨细胞修复兔关节软骨缺损中的作用

[目的]探讨补肾行气活血法在骨髓基质于细胞诱导软骨细胞修复兔关节软骨缺损中的作用. [方法]将胶原凝胶包埋的骨炎定含药血清培养的骨髓基质干细胞诱导的软骨细胞和异体软骨细胞接种CPPf/PLLA支架构建的复合物体外培养3周,行倒置显微镜和扫描电镜观察,并将复合物异体移植入兔关节软骨缺损,术后4、8、12周取材,从大体、组织学和Ⅱ型胶原免疫组织化学分别对再生软骨组织进行评价. [结果]诱导软骨细胞组在支架内分布均匀、透明软骨样组织的形成、表面光滑度、与周围组织整合程度及基质内有Ⅱ型胶原分布等方面明显优于软骨细胞组. [结论]补肾行气活血法在关节软骨缺损修复的作用中较传统的方法有其优越性.     

微粒软骨脱细胞基质复合纤维蛋白凝胶构建软骨组织工程支架材料的研究

目的：应用异体微粒软骨脱细胞基质与纤维蛋白凝胶结合作为可注射性支架材料，进行体内构建良好可塑性和生物特性的组织工程化软骨。方法：制备普通家猪耳廓软骨微粒脱细胞基质，与体外扩增的小型实验猪第二代软骨细胞结合，以纤维蛋白凝胶为支架材料，利用其可注射性回植于实验猪自体腹壁外侧皮下，8周后取财进行大体及组织学检测，并与不合微粒脱细胞软骨基质实验组相比较。结果：培养出的组织工程化软骨组织细胞生长良好，具有分泌软骨基质功能，含微粒脱细胞软骨基质实验组表现出更佳的生物学性能。结论：将异体微粒软骨脱细胞基质与纤维蛋白凝胶结合，可以作为良好的可注射性复合支架材料应用于组织工程化软骨的构建。     

胶原凝胶包埋软骨细胞复合聚磷酸钙纤维/左旋聚乳酸支架异体移植修复兔关节软骨缺损

目的探讨胶原凝胶包埋软骨细胞复合聚磷酸钙纤维／左旋聚乳酸(CPPf／PLLA)支架异体移植修复兔关节软骨缺损的有效性和可行性。方法将胶原凝胶包埋的软骨细胞接种CPPf/PLLA支架构建的复合物体外培养3周，行倒置显微镜和扫描电镜观察，并将复合物异体移植入兔关节软骨缺损，术后4、8、12周取材，从大体、组织学和Ⅱ型胶原免疫组织化学对再生软骨组织进行评价。结果复合物体外培养3周，细胞被大量基质包裹，在支架内分布均匀；新形成的组织为透明软骨样组织、表面光滑且与周围组织整合良好、基质内有Ⅱ型胶原分布。结论胶原凝胶包埋软骨细胞接种CPPf／PLLA支架的方法能提高细胞一支架复合物构建质量，胶原凝胶复合CPPf／PLLA支架可作为软骨细胞载体修复关节软骨缺损。     

骨形成蛋白2基因修饰的骨髓基质细胞与纤维蛋白复合物修复兔关节软骨缺损

目的 研究骨形成蛋白2（bone mophogenetic protein2，BMP-2）重组腺病毒（adenovirus）转染骨髓基质细胞（mesenchymal stem cells，MSCs）后，与纤维蛋白凝胶构成的复合物（Ad—BMP-2＋MSCs-纤维蛋白凝胶）对兔关节软骨缺损修复的影响。方法 ①AdBMP-2转染原代培养的MSCs，通过RT—PCR、细胞免疫组织化学染色、甲苯胺蓝染色等观察转染后3～9d的MSCs其BMP-2、Ⅱ型胶原及蛋白多糖转录、表达水平的变化。②转染后的MSCs种植于纤维蛋白凝胶，在体外培养1～9d，通过上述指标及透射电镜观察三维培养条件下其软骨基质的产生。③42只日本大耳白兔先制成直径4．5mm全层软骨缺损模型，随机分为3组（n=14）：A组为Ad—BMP-2＋MSCs-纤维蛋白凝胶修复组，B组为MSCs-纤维蛋白凝胶修复组，C组为空白对照组。术后4、8和12周取材行大体观察、HE染色、甲苯胺蓝染色、Ⅱ型胶原免疫组织化学及12周关节软骨弹性常数检测。结果 ①Ad—BMP-2转基因MSCs的BMP-2、Ⅱ型胶原mRNART—PCR检测分别在3、5d呈阳性，与对照组比较差异有统计学意义（P〈0．05）。②转基因MSCs三维培养物免疫组织化学和甲苯胺蓝染色呈阳性，电镜显示细胞生长良好，有基质合成。③A组各时间点大体、组织形态学和组织化学染色均显著优于B组和C组，12周时力学和组织学已接近正常关节软骨。结论 Ad—BMP-2能通过促进MSCs分泌BMP-2，诱导Ⅱ型胶原和蛋白多糖的表达，在纤维蛋白三维支架中形成软骨基质，移植入兔关节软骨缺损区可修复直径4．5mm缺损，其修复组织成分接近正常软骨。     

软骨脱细胞基质-Ⅱ型胶原纳米支架复合BMSC修复兔关节软骨缺损的实验研究

目的 观察软骨脱细胞基质(Cartilage acellular extracellular matrix,CAEM)-Ⅱ型胶原(CollagenⅡ,COLⅡ)纳米支架,复合骨髓基质干细胞(Bone marrow stem cells,BMSCs)修复兔关节软骨缺损的效果。方法 CAEM和COLⅡ按质量比1∶1混合,通过静电纺丝技术制备组织工程纳米支架。将第二代BMSCs种植到该支架上,培养箱内静置2 h。12只日本大耳白兔随机分为实验组和对照组,将细胞支架复合物植入实验组兔膝关节软骨缺损处,对照组仅行膝关节软骨缺损建模。12周后实验动物取材,大体观察修复效果,并行HE染色、Ⅱ型胶原染色观察。结果 大体观察见实验组软骨缺损修复良好,对照组软骨缺损处由肉芽样组织充填。HE染色显示,实验组关节软骨缺损处可见软骨陷窝形成,对照组关节软骨缺损处仅有纤维组织充填。实验组修复区Ⅱ型胶原染色为阳性,对照组为阴性。结论 CAEM-COLⅡ纳米支架复合BMSC,对兔关节软骨缺损具有较好的修复能力,具有潜在的临床应用价值。     

双相支架负载软骨细胞修复兔关节软骨缺损

目的研究自固化磷酸钙/纤维蛋白凝胶(CPC/FG)双相支架负载软骨细胞修复兔关节软骨缺损的可行性和有效性.方法将分离培养的第3代软骨细胞包埋在CPC/FG双相支架的FG中,体外培养1周后,将软骨细胞-支架复合体移植修复兔膝关节股骨髁的软骨缺损(φ4 mm,深3.5 mm,达软骨下骨质).然后对软骨缺损的修复情况进行大体、光镜和电镜观察.同时对移植后第12周的修复软骨进行胶原含量测定,并与正常的关节软骨细胞胶原含量进行比较.结果移植的软骨细胞能在双相支架上良好地生长,软骨缺损以透明软骨的形式被修复,而对照组为纤维组织修复.多孔自固化磷酸钙在软骨修复过程中能起软骨下骨的临时替代作用.胶原含量测定显示:移植术后12周的修复软骨胶原含量为(43.25±0.85)%;正常的关节软骨胶原含量为(55.69±0.76)%,两者差异有显著性(P<0.01).结论 CPC/FG双相支架负载软骨细胞能以透明软骨的形式修复兔关节软骨缺损.新环境中移植的软骨细胞生长的不适应和FG降解过快,可能是导致新生修复软骨与自身正常关节软骨胶原含量有差异的原因.     

骨髓基质细胞体外增殖后移植修复关节软骨缺损的实验研究

目的 :用组织工程的方法将骨髓基质细胞体外培养增殖后植入软骨缺损 ,观察关节软骨缺损的修复效果。方法 :抽取兔骨髓基质细胞体外培养增殖后 ,将其与Ⅱ型胶原凝胶相结合 ,植入到兔膝关节实验性关节软骨缺损中 ,对照组的缺损分别置入与髓腔血混合的Ⅱ型胶原凝胶、单纯Ⅱ型胶原凝胶或不作任何处理 ,术后 4、8、12周取材观察及组织学检查。结果 :术后 4周 ,实验组的缺损由透明样软骨样组织充填 ,术后 12周 ,软骨及软骨下骨组织基本修复 ;在对照组缺损 ,软骨下骨在术后 12周亦基本修复 ,但表层软骨主要由纤维组织修复。结论 :骨髓基质细胞来源丰富 ,采集方便 ,经体外培养增殖后 ,足量的未分化细胞与Ⅱ型胶原凝胶载体相结合 ,修复关节软骨缺损的效果较好。     

组织工程软骨对兔膝关节胫骨平台浅层全关节软骨缺损的修复作用

目的探讨组织工程软骨对兔膝关节胫骨平台外侧髁浅层全关节软骨缺损的修复作用，并检测其修复组织的软骨类型。方法取2周龄乳兔软骨细胞体外培养传代至第3代后，与人胎盘Ⅰ型胶原蛋白海绵复合后植入成年兔的胫骨平台外侧髁完全软骨缺损区，并设立空白对照组，分别于术后4、12、24周取材。观察修复效果。运用天狼星红染色检测Ⅰ型胶原，Ⅱ型胶原单克隆抗体检测Ⅱ型胶原的表达。结果实验组术后4周缺损表面未见明显的新生软骨形成，组织学切片上少数几个呈上皮样生长的软骨细胞，苏木素-伊红（HE）染色胞浆呈深蓝色，周围软骨基质染色成浅蓝色；12周，缺损表面有少量的新生软骨形成，组织学切片上可见软骨细胞呈边缘不规则的，小蜂窝状结构，软骨细胞周围有软骨陷窝形成；24周，缺损表面的新生软骨较4、12周的新生软骨明显，表面光滑，且与周围组织结合紧密，但仍存在部分缺损尚未修复，组织学切片上可见软骨细胞呈边缘不规则的，多层细胞的蜂窝状结构，软骨细胞周围有软骨陷窝形成，并分泌甲苯胺蓝异染的软骨基质。而对照组则均未见明显的修复；随着术后时间的延长，Ⅰ型胶原的表达呈逐渐减弱的趋势，而Ⅱ型胶原的表达呈逐渐增强的趋势。结论该方法制成的组织工程软骨对兔胫骨平台外侧髁全层软骨缺损有修复作用，运用该方法不能完全修复兔胫骨平台外侧髁软骨完全缺损；形成的新生软骨为透明软骨样组织。     

藻酸钙复合自体软骨细胞修复羊膝关节负重区软骨缺损的实验研究

[目的]以中国山羊为动物模型,观察藻酸钙复合自体软骨细胞修复膝关节负重区软骨缺损的可行性。[方法]取羊肩关节软骨,分离、培养软骨细胞,蕃红"O"、 Giemsa及Ⅱ型胶原免疫组织化学染色对其进行鉴定。将自体软骨细胞与藻酸钙凝胶复合,修复山羊股骨髁负重区全层软骨缺损(直径6 mm),实验分为四组:(1)缺损旷置组:缺损内未植入任何组织;(2)骨膜覆盖组:自体骨膜覆盖缺损区;(3)藻酸钙+骨膜组:凝胶植入软骨缺损区,并用自体骨膜覆盖;(4)藻酸钙+细胞+骨膜组:藻酸钙复合自体软骨细胞植入软骨缺损区,自体骨膜覆盖;分别于手术后3、6个月取材,通过大体观察及组织学评分检测修复效果。[结果]软骨细胞复合物蕃红"O"、 Giemsa染色及Ⅱ型胶原免疫组化染色结果均为阳性,将藻酸钙凝胶-软骨细胞复合物用于羊负重区关节面软骨缺损修复,从大体观察和组织学评分进行比较,发现各组均有不同程度的组织修复,藻酸钙+细胞+骨膜组效果最好,与其他组差异有统计学意义(P<0.05)。[结论]藻酸钙凝胶-软骨细胞复合物结合自体骨膜覆盖,可较好修复山羊膝关节负重区软骨缺损。     

松质骨基质复合生物蛋白胶构建组织工程软骨的研究

目的尝试采用松质骨基质与生物蛋白胶复合材料构建组织工程软骨。方法体外培养大鼠软骨细胞,接种于松质骨基质／生物蛋白胶材料上行体外培养。采用HE、甲苯胺蓝染色免疫学检测、扫描电镜观察等方法观察所构建的组织工程软骨的特性。结果松质骨基质／生物蛋白胶组的组织学结构更接近于软骨样组织．其Ⅱ型胶原、蛋白多糖基因表达量及蛋白多糖含量明显高于松质骨基质组。结论松质骨基质／生物蛋白胶复合材料可用于构建组织工程软骨,是一种较理想的支架材料。     

同种异体脱钙骨复合骨髓间充质干细胞在兔膝关节腔内培养组织工程软骨的研究

目的 比较同种异体脱钙骨和细胞因子诱导骨髓间充质干细胞(BMSC)制成细胞-支架复合物在兔膝关节腔内环境较体外培养出组织工程软骨的优点.方法 BMSC向软骨细胞诱导后与同种异体脱钙骨支架复合分别在体外培养(A组)和成年雄性新西兰白兔(15只)左侧膝关节腔内(B组)培养,右侧膝关节腔内(C组)培养单纯脱钙骨支架做空白对照.每4、8、12周各组标本分别取材,制石蜡切片行苏木素-伊红(HE)染色、甲苯胺蓝染色、Ⅱ型胶原免疫组织化学等组织学观察,并通过形态学分析软件计算免疫组织化学平均光度(A)值.结果 标本石蜡切片HE染色:4周时A组标本见软骨细胞散在分布于支架表面,内部基本未观察到细胞.B组标本支架内软骨细胞数量明显较多,软骨陷窝形成,陷窝周围基质深染,可见由单个细胞分裂形成的同源细胞群.8周时B组标本以成熟软骨细胞为主,细胞数量多,出现柱状排列的同源细胞群,细胞周围分泌着色均一的玻璃样基质,且渗入支架结构内部,脱钙骨支架有部分被吸收.12周时各组支架结构明显被吸收,A组支架内填满软骨细胞,部分已纤维化,但结构排列紊乱.B组支架呈透明软骨样,软骨细胞充分渗透进入支架内,呈一定应力方向排列.Ⅱ型胶原免疫组织化学A值统计学分析比较发现:第4,8,12周B组Ⅱ型胶原免疫组织化学的A值均高于A组,差异有统计学意义(P＜0.01).两组间A值随时间的变化趋势差异有统计学意义(P＜0.01).结论 同种异体脱钙骨支架复合经细胞因子诱导的BMSC,在膝关节腔内进行培养,利用关节腔内低氧、多种生长因子的微环境以及关节活动时的应力刺激等优势,较体外培养可以培养出组织学特点更好的工程软骨.

Abstract：

Objective To compare the superiority of cultivating tissue engineered cartilage by homologous decalcified bone matrix combined with bone-marrow mesenchymal stem cells (BMSCs) in rabbits' knee cavity with culture in vitro. Methods Archiogeneration BMSCs were isolated and purified by adhering to the culture glassware wall from neonatal New Zealand white rabbits. The third generation BMSCs were induced to chondrocytes by transforming growth factor TGF-β1, insulin-like growth factor IGF-1 and vitamin C. Seven days later, the cells were bond to homologous decalcified bone matrix and cultured in vitro (group A) , cultured in rabbits' left knee cavity (group B) , or bond to homologous decalcified bone matrix and cultured in rabbits' right knee cavity ( group C ). Every 4 weeks after cellular transplant, all rabbits in groups B and C were sacrificed and paraffin-embedded sections were made from the specimens.All the section were subjected to H-E stain, toluidine blue stain and type Ⅱ collagen immunohistochemical staining with chromogen diaminobenzidine ( DAB) . Immunohistochemical absorbance ( A) values were calculated by morphology analysis software. Measurement data were expressed as mean ± standard, and satistical analysis was performed by t test, one-way ANOVA using SPSS 15. 0 software. Results After cultivation for 4 weeks, H-E stain showed diffuse distribution of chondrocytes on scaffold' s surface in group A.In group B, there were a great quantity of chondrocytes in the scaffold, and cartilage lacuna, matrix anachromasis and isogenous group were group. At the 8th week, in group B maturated chondrocytes and isogenous groups arranged as column, surrounded by a pond of cellular matrix infiltrating into the scaffolds. The decalcified bone matrix was absorbed partly. At the 12th week, all the scaffolds were absorbed obviously.Chondrocytes filled into the scaffolds in group A, but arranged irregularly. In group B chondrocytes arranged in the stress orientation. At 4th, 8th, and 12th week, A values of type Ⅱ collagen in group B was significantly higher than in group A with the different being significant. Conclusion Compound of Homologous decalcified bone matrix-induced BMSCs cultured in rabbits' knee cavity could yield better histological feature tissue engineered cartilage.     

以PHBV为支架构建组织工程化软骨

[目的]探讨聚（羟基丁酸酯．羟基戊酸酯）（PHBV）多孔材料作为软骨组织工程支架的可行性以及体内外培养方式对软骨形成的影响。[方法]采用“压片-热处理-粒子析出”技术制备PHBV多孔支架。体外分离培养软骨细胞后接种到PHBV支架体外培养2周，期间扫描电镜观察细胞在支架上的生长情况，然后与单纯PHBV支架同植入裸鼠皮下继续培养4、8周后取材，与体外培养至6、10周的细胞一支架复合物同行组织学观察。[结果]电镜观察示软骨细胞在支架上黏附、增殖良好并能分泌细胞外基质；组织学观察示PHBV浅层有新生软骨组织形成，且皮下培养的软骨组织比体外培养的更为成熟。单纯PHBV支架皮下培养没有软骨组织形成。[结论]PHBV可以作为软骨组织工程支架材料。体内培养较体外更有利于组织工程化软骨的形成。     

Evaluation of the ability of natural and synthetic scaffolds in providing an appropriate environment for growth and chondrogenic differentiation of adipose-derived mesenchymal stem cells

Background:

Although progenitor cells have been observed in articular cartilage, this part has a limited ability to repair due to a lack of blood supply. Formerly, tissue engineering was mainly based on collecting chondrocytes from the joint surface, culturing them on resorbable scaffolds such as poly D, L-lactic glycolic acid (PLGA) and then autologous transplantation. In recent times, due to difficulties in collecting chondrocytes, most of the researchers are focused on stem cells for producing these cells. Among the important factors in this approach, is using appropriate scaffolds with good mechanical and biological properties to provide optimal environment for growth and development of stem cells. In this study, we evaluated the potential of fibrin glue, PLGA and alginate scaffolds in providing a suitable environment for growth and chondrogenic differentiation of mesenchymal stem cells (MSCs) in the presence of transforming growth factor-β3.

Materials and Methods:

Fibrin glue, PLGA and alginate scaffolds were prepared and MSCs were isolated from human adipose tissue. Cells were cultured separately on the scaffolds and 2 weeks after differentiation, chondrogenic genes, cell proliferation ability and morphology in each scaffold were evaluated using real time-polymerase chain reaction, MTT chondrogenic assay and histological examination, respectively.

Results:

Proliferation of differentiated adipose tissue derived mesenchymal stem cells (AD-MSCs) to chondrogenic cells in Fibrin glue were significantly higher than in other scaffolds. Also, Fibrin glue caused the highest expression of chondrogenic genes compared to the other scaffolds. Histological examination revealed that the pores of the Fibrin glue scaffolds were filled with cells uniformly distributed.

Conclusion:

According to the results of the study, it can be concluded that natural scaffolds such as fibrin can be used as an appropriate environment for cartilage differentiation.     

海螵蛸与兔软骨细胞组织的生物相容性

目的 探讨海螵蛸作为新生兔关节软骨体外细胞培养支架材料的可行性.方法 消化分离新生兔关节软骨细胞,接种于自制海螵蛸片支架上培养,从倒置相差显微镜和扫描电镜观察其亲水性和对细胞的吸附力.结果 预湿海螵蛸支架的亲水性优于未预湿海螵蛸支架,使软骨细胞更易扩散至支架孔隙.软骨细胞-支架复合体培养1周后,细胞开始在预湿海螵蛸支架上黏附、伸展、增殖;2周后细胞融合成片,布满整个支架孔隙并产生基质.结论 海螵蛸多孔支架与兔软骨细胞具有良好的生物相容性,可以作为软骨组织工程中细胞培养支架的新材料.     

人脂肪来源细胞体内构建组织工程化脂肪的实验研究

目的探讨以组织工程技术，应用脂肪来源细胞（Adipose—derived cells，ADCs）体内构建脂肪组织的可行性。方法吸脂术获得人脂肪组织，一部分直接植入裸鼠体内；另一部分用酶消化法分离、培养ADCs，将第三代细胞接种于纤维凝胶（Fibrin glue）支架中，经成脂肪培养液诱导1周后，植入裸鼠体内，4周后取材，用称重法及油红、HE染色检测结果。实验分为直接注射脂肪组、单纯支架组、细胞-支架复合体脂肪诱导组、非诱导组。结果直接注射组在裸鼠皮下形成脂肪组织，但吸收量大；细胞-支架复合体诱导组有大量脂肪类组织形成，油红染色显示组织有脂滴形成；细胞-支架复合体非诱导组和单纯支架组均未发现脂肪组织形成。结论采用组织下程技术将吸脂术获得脂肪来源细胞接种纤维凝胶支架，体内构建脂肪组织，具有可行性。     

iNOS抑制剂对兔关节软骨修复组织胶原表达的影响

目的观察诱导型一氧化氮合酶抑制剂对关节软骨修复组织胶原表达的影响。方法24只新西兰大白兔双侧股骨髁间关节面造成全层软骨缺损。随机抽签均分为对照组、骨形态发生蛋白（bone morphogenetic protein,BMP）组和一氧化氮合酶抑制剂S-甲基异硫脲组（S—methylisothiourea,SMT）组。术后1年处死动物。应用苦味酸-天狼猩红染色检测胶原的分布情况,图像分析技术定量胶原的表达及进行修复组织软骨厚度的测量。应用免疫组织化学技术检测Ⅱ型胶原的表达和分布。结果图像分析显示,1年后SMT组I型胶原表达量为65．9％,明显少于BMP组88．5％和对照组94．6％的表达量,Ⅱ型胶原30．7％的表达量明显多于BMP组10．8％和对照组4．5％的表达量。1年后SMT组软骨厚度（1．85±0．56）mm明显高于BMP组（0．67±0．31）mm和对照组（0．24土0．10）mm。SMT组缺损区Ⅱ型胶原含量明显高于BMP组和对照组。结论iN0s抑制剂SMT的应用能明显增加Ⅱ型胶原表达和软骨厚度,对于维持软骨表型有积极意义。     

Cartilage Tissue Engineering With Demineralized Bone Matrix Gelatin and Fibrin Glue Hybrid Scaffold: An In Vitro Study

To develop a cartilage‐like tissue with hybrid scaffolds of demineralized bone matrix gelatin (BMG) and fibrin, rabbit chondrocytes were cultured on hybrid fibrin/BMG scaffolds in vitro. BMG scaffolds were carefully soaked in a chondrocyte–fibrin suspension, which was polymerized by submerging the constructs into thrombin–calcium chloride solution. Engineered cartilage‐like tissue grown on the scaffolds was characterized by histology, immunolocalization, scanning electron microscopy, biochemical assays, and analysis of gene expression at different time points of the in vitro culture. The presence of proteoglycan in the fibrin/BMG hybrid constructs was confirmed by positive toluidine blue and alcian blue staining. Collagen type II exhibited intense immunopositivity at the pericellular matrices. Chondrogenic properties were further demonstrated by the expression of gene‐encoded cartilage‐specific markers, collagen type II, and aggrecan core protein. The glycosaminoglycan production and hydroxyproline content of tissue grown on the fibrin/BMG hybrid scaffolds were higher than that of the BMG group. In conclusion, the fibrin/BMG hybrid scaffolds may serve as a potential cell delivery vehicle and a structural basis for cartilage tissue engineering.     

Tissue engineering of tendons and ligaments by human bone marrow stromal cells in a liquid fibrin matrix in immunodeficient rats: Results of a histologic study

Introduction The original complex structure and mechanical properties are not fully restored after ligament and tendon injuries. Due to their high proliferation rate and differentiation potential, Bone Marrow Stromal Cells (BMSC) are considered to be an ideal cell source for tissue engineering to optimize the healing process. Ideal matrices for tissue engineering of ligaments and tendons should allow for homogenous cell seeding and offer sufficient stability. Material and methods A mixture of human BMSC and liquid fibrin glue was injected into a standardized full-thickness window defect of the patellar tendon of immunodeficient rats (BMSC group). The histology of the tissue was analysed 10 and 20 days postoperatively and compared to four control groups. These groups consisted of a cohort with a mixture of human fibroblasts and fibrin glue, fibrin glue without cells, a defect group without treatment, and a group with uninjured patellar tendon tissue. Results Tendon defects in the BMSC group revealed dense collagen fibres and spindle-shaped cells, which were mainly orientated along the loading axis. Histologic sections of the control groups, especially of untreated defects and of defects filled with fibrin glue only, showed irregular patterns of cell distribution, irregular formed cell nucleoli and less tissue maturation. Compared to healthy tendon tissue, higher numbers of cells and less intense matrix staining was observed in the BMSC group. No ectopic bone or cartilage formation was observed in any specimen. Conclusions Injection of human BMSC in a fibrin glue matrix appears to lead to more mature tissue formation with more regular patterns of cell distribution. Advantages of this “in-vivo” tissue engineering approach are a homogenous cell-matrix mixture in a well-known and approved biological matrix, and simple, minimally-invasive application by injection.