组织工程软骨与柚皮苷联合修复兔膝关节软骨缺损的组织学证实

背景：目前临床上虽有多种方法用于治疗软骨缺损,但没有从根本上解决关节软骨缺损修复问题。目的：通过组织学研究进一步评价柚皮苷结合组织工程软骨修复兔关节软骨缺损的效果。方法：取兔骨髓间充质干细胞体外增殖后,复合于改建后的脱细胞真皮基质载体上,制成组织工程软骨,植入到兔膝关节软骨缺损,并以柚皮苷汤灌胃,于4,8周后分别对修复组织进行苏木精-伊红、Masson三色染色、甲苯胺蓝染色、Ⅱ型胶原染色、Ⅹ型胶原染色等组织学检查。结果与结论：术后8周,柚皮苷结合干细胞复合体组缺损处修复组织变成乳白色,半透明光滑组织,缺损修复组织与周围正常软骨已基本难区分,表面光滑。组织学检查发现修复缺损处基本为新生软骨填充。结果证实,柚皮苷结合组织工程软骨能提高家兔膝关节软骨缺损的修复质量。     

Use of stem cells in the biological repair of articular cartilage

Importance of the field: Articular cartilage is avascular, aneural, and renowned for its poor capacity to repair after damage. For decades scientists and clinicians have deliberated over the potential to repair or regenerate articular cartilage and to date many techniques have been used in an attempt to create the best possible repair tissue.

Areas covered in this review: This review article summarises surgical interventions that have been developed since the late 1940's; covering conservative strategies, invasive techniques and touching upon latest advancements involving stem cells and tissue engineering.

What will the reader gain: The reader will gain a sound understanding into the history and background of strategies that have developed in attempts to reverse clinical symptoms of damaged or diseased articular cartilage. The article provides an insight into the plethora of potential repair mechanisms, and reviews future developments involving stem cells and biomaterials.

Take home message: Although work is still in its infancy, the use of stem cells in the biological repair of articular cartilage provides a promising outlook onto future developments; advancing from strategies and techniques that are already in use.     

生物组织粘合剂对软骨修复材料和修复过程的影响

目的探讨组织粘合剂对软骨修复材料和修复过程的影响。方法硫酸铵方法提取猪血制备纤维蛋白原胶,用于粘合关节软骨、骨膜和筋膜软骨细胞修复材料修复关节软骨缺损,术后6、12和24周后取材,通过大体、光镜和放射自显影方法观察,并与化学性医用胶进行比较。结果生物组织粘合剂具有粘合可靠,使用方便,止血好,无有害作用,并不影响修复材料的愈合、生长;化学胶不仅对修复材料有损害作用,对修复部位有同样损伤作用,导致受损伤部位组织细胞死亡。结论纤维蛋白原胶可以用于粘合软骨修复材料,化学性医用胶对软骨修复材料和修复部位有损害作用。     

Characterization of costal cartilage and its suitability as a cell source for articular cartilage tissue engineering

Costal cartilage is a promising donor source of chondrocytes to alleviate cell scarcity in articular cartilage tissue engineering. Limited knowledge exists, however, on costal cartilage characteristics. This study describes the characterization of costal cartilage and articular cartilage properties and compares neocartilage engineered with costal chondrocytes to native articular cartilage, all within a sheep model. Specifically, we (a) quantitatively characterized the properties of costal cartilage in comparison to patellofemoral articular cartilage, and (b) evaluated the quality of neocartilage derived from costal chondrocytes for potential use in articular cartilage regeneration. Ovine costal and articular cartilages from various topographical locations were characterized mechanically, biochemically, and histologically. Costal cartilage was stiffer in compression but softer and weaker in tension than articular cartilage. These differences were attributed to high amounts of glycosaminoglycans and mineralization and a low amount of collagen in costal cartilage. Compared to articular cartilage, costal cartilage was more densely populated with chondrocytes, rendering it an excellent chondrocyte source. In terms of tissue engineering, using the self‐assembling process, costal chondrocytes formed articular cartilage‐like neocartilage. Quantitatively compared via a functionality index, neocartilage achieved 55% of the medial condyle cartilage mechanical and biochemical properties. This characterization study highlighted the differences between costal and articular cartilages in native forms and demonstrated that costal cartilage is a valuable source of chondrocytes suitable for articular cartilage regeneration strategies.     

组织工程化软骨修复界面整合的体外模型

背景：随着组织工程学的发展,自体软骨细胞移植技术经常被用来修复软骨缺损,整合不良是导致修复失败的原因之一。许多体外模型被用来进行这方面的研究。 目的：建立一种组织工程化软骨修复界面整合的体外实验模型并评价其效果。 方法：制备猪体外软骨整合模型,获得21个软骨环,18只琼脂糖凝胶覆盖的软骨环设为琼脂糖凝胶组,剩余3个做无琼脂糖对照组,分别植入分离的软骨细胞,观察近期软骨环边界细胞漏出情况,分别在1,2,4周做切片、染色并行组织学观察,测量新生软骨平均面积并进行比较。 结果与结论：无琼脂糖对照组由于软骨细胞早期从软骨环底部漏出,未能在软骨环中形成软骨细胞聚集,所以未做后期处理,而琼脂糖凝胶组则未发生。琼脂糖凝胶组1,2,4周做切片并行固定后组织切片分别用苏木精-伊红染色、阿利新蓝、番红O、Ⅱ型胶原免疫组化染色,移植的软骨细胞在软骨环内不断增殖,并且产生细胞外基质。在第1,2周的孵育中,新生软骨的面积明显增大,到第4周时,面积也有进一步增加,但是第2-4周的面积增加,差异无显著性意义（P〉0.05）。模型成功模拟了自体软骨细胞移植修复关节软骨缺损的体外整合过程,未来可应用于软骨整合及软骨组织工程的机制研究。     

3D ingrowth of bovine articular chondrocytes in biodegradable cryogel scaffolds for cartilage tissue engineering

A feasibility study was undertaken to examine the potential of biodegradable HEMA-lactate-dextran (HEMA-LLA-D)-based cryogels as scaffolds for cartilage tissue engineering. This was a preliminary in vitro study giving essential information on the biocompatibility of cryogels with cartilage cells. HEMA-lactate (HEMA-LLA) and HEMA-LLA-D were synthesized and characterized by different techniques. Cryogel scaffolds with supermacroporous structures were produced by cryogenic treatment of these macromers. Chondrocytes obtained from bovine articular cartilage were seeded onto cylindrical cryogels and cultured. The samples were examined by several microcopical techniques for cell viability and morphological analyses were performed at two culture points. Histological study of the constructs revealed the cells' growth on the surface and within the scaffolds. Confocal microscopical images demonstrated that the majority of live vs. dead cells had been attached to and integrated with the pores of the scaffold. SEM analysis showed round to oval-shaped chondrocytic cells interconnected with each other by communicating junctions. The chondrocytes rapidly proliferated in the cryogels, manifesting that they fully covered the scaffold surface after 9 days and almost filled the spaces in the pores of the scaffold after 15 days of culture. Chondrocytes secreted significant amount of extracellular matrix in the scaffolds and exhibited highly interconnective morphology. Light and transmission electron microscopy revealed groups of active cartilage cells closely apposed to the cryogel. We concluded that cryogel scaffolds could be excellent candidates for cartilage tissue regeneration with their extraordinary properties, including soft, elastic nature, highly open interconnected pore structure and very rapid, controllable swellability.     

间充质干细胞在关节软骨组织工程中的应用

背景：组织工程技术的发展为关节软骨缺损修复和功能重建提供了新的方法和思路。目的：探讨以间充质干细胞作为种子细胞在关节软骨组织工程中的应用和研究进展。 方法：由第一作者检索 PubMed 数据库中2000-01-01/2014-09-30有关间充质干细胞和关节软骨组织工程的文献,检索词为“articular cartilage defects, cartilage tissue engineering, mesenchymal stem cel s”。共检索到70篇相关文献,对其中49篇文献进行综述。 结果与结论：关节软骨缺损自身修复能力很有限,目前的临床治疗手段无法达到满意修复,而组织工程的发展为解决这个问题提供了新思路。在种子细胞选择方面,软骨细胞去分化能力有限,胚胎干细胞受到伦理、法律等方面的制约,而间充质干细胞因其自体来源、易扩增、具有软骨分化潜能而受到广泛重视。但目前应用组织工程方法修复关节软骨缺损的效果存在一定的争议,主要是远期功能距离临床应用存在一定差距,在修复组织结构和生物力学方面还需要进一步研究。     

组织工程技术修复损伤关节软骨的研究与应用

背景：软骨是一种无血管的组织,软骨损伤后自身修复能力有限。当前用于治疗关节软骨损伤的方法从保守治疗到手术治疗多种多样。随着组织工程技术的发展,关节软骨的修复又进入了新的高度。目的：综述组织工程方法修复软骨损伤的新进展。方法：由第一作者在2013年5月应用计算机检索2000至2013年PubMed 数据库及CNKI 数据库,英文以“cartilage tissue engineering,cartilage defect;stem cel ,scaffold;growth factor”为关键词,中文以“软骨组织工程,软骨缺损,干细胞,支架,生长因子”为关键词,选择内容与软骨组织工程、软骨损伤修复相关的文章,同一领域文献则选择近期发表或发表在权威杂志文章,共纳入64篇文献。结果与结论：软骨组织工程三大要素--种子细胞、支架和细胞因子,三者必须协调发展和互利。现阶段组织工程方法修复关节软骨损伤的研究虽已取得很大进展,但大多停留于实验探索阶段,尚未应用于临床。随着新材料的不断研发,新的组织工程软骨修复材料将兼顾材料学和生物科学的需要,使其更接近机体自身组织生物学特性。在新的技术支持下,动物实验研究也将向临床试验转变,使关节软骨损伤的治疗取得突破性进展。     

富血小板血浆复合软骨细胞构建可注射性组织工程化软骨

背景：富血小板血浆中含有大量的生长因子,因此其在骨再生、创伤愈合等方面得到了较多的应用,然而其在组织工程软骨的研究报道较少。 目的：观察富血小板血浆对软骨细胞增殖和分化的影响,以及富血小板血浆复合软骨细胞构建组织工程化软骨的可行性。 方法：检测兔全血、富血小板血浆及激活富血小板血浆中转化生长因子β、胰岛素样生长因子1、血小板源性生长因子BB及表皮生长因子的浓度。将兔软骨细胞在分别含10％,15％,20％,30％富血小板血浆的DMEM培养液中培养7d,CCK-8法检测细胞增殖,QT-PCR检测细胞内II型胶原、蛋白聚糖、Sox-9的表达。在兔皮下注射自体富血小板血浆与软骨细胞复合物,6周后取材进行组织学检测。结果与结论：富血小板血浆中各生长因子浓度高于全血（P〈0．05）,激活富血小板血浆中各生长因子浓度高于富血小板血浆（P〈0．05）。不同浓度富血小板血浆均能促进软骨细胞的增殖,且20％浓度内呈浓度依赖性。20％浓度组促II型胶原表达的能力强于其他浓度组（P〈0．05）,15％浓度组促Sox-9和蛋白聚糖表达的能力强于其他浓度组（P〈0．05）。富血小板血浆一软骨细胞复合物移植后,新生组织呈软骨样并有明显的软骨陷窝,细胞外富含软骨样基质,表明其作为可注射性支架用于软骨组织工程。     

聚乙烯醇及其复合材料在组织工程支架中的应用

背景：聚乙烯醇是具有良好生物相容性和生物降解特性的聚合物,因其水溶性、成膜性、乳化性、胶黏性,而且无味无毒,被广泛用于临床领域。
　　目的：综述聚乙烯醇及其复合材料在骨、软骨、皮肤、血管等组织工程支架中的应用。
　　方法：由第一作者检索2000年1月至2011年12月中国知网数据库、1980年1月至2012年12月Pubmed数据库及 Elsevier数据库中,有关聚乙烯醇及其复合材料在骨、软骨、皮肤、血管等组织工程支架中应用的文章,中文关键词为“聚乙烯醇,复合材料,组织工程支架”,英文关键词为“Poly (vinyl alcohol),composite material, tissue engineering scaffold”。
　　结果与结论：虽然聚乙烯醇及其复合材料还存在强度不够高、植入后有并发症等缺点,但这类材料具有良好的生物相容性和生物可降解特性,在组织工程中的应用从实验室到临床前研究都有很大的进展。对于其修复的长期效果还需要进一步深入研究。通过对材料表面进行修饰,改善细胞与支架材料的相互作用;通过模拟细胞生长微环境,制备仿生材料,提高材料的亲水性、对细胞的黏附性,促进细胞的分化增殖;构建具有可控三维多孔结构的支架,并赋予其控制释放细胞生长因子等功能,更好地仿生天然细胞外基质的结构和功能;制备出降解速度与机械强度能够完全适应组织再生需要的支架,研制复合、仿生材料是今后支架材料研究的主要方向。     

Efficacy of thermoresponsive,photocrosslinkable hydrogels derived from decellularized tendon and cartilage extracellular matrix for cartilage tissue engineering

Tissue engineering using adult mesenchymal stem cells (MSCs), a promising approach for cartilage repair, is highly dependent on the nature of the matrix scaffold. Thermoresponsive, photocrosslinkable hydrogels were fabricated by functionalizing pepsin‐soluble decellularized tendon and cartilage extracellular matrices (ECM) with methacrylate groups. Methacrylated gelatin hydrogels served as controls. When seeded with human bone marrow MSCs and cultured in chondrogenic medium, methacrylated ECM hydrogels experienced less cell‐mediated contraction, as compared against non‐methacrylated ECM hydrogels. However, methacrylation slowed or diminished chondrogenic differentiation of seeded MSCs, as determined through analyses of gene expression, biochemical composition and histology. In particular, methacrylated cartilage hydrogels supported minimal due to chondrogenesis over 42 weeks, as hydrogel disintegration beginning at day 14 presumably compromised cell–matrix interactions. As compared against methacrylated gelatin hydrogels, MSCs cultured in non‐methacrylated ECM hydrogels exhibited comparable expression of chondrogenic genes (Sox9, Aggrecan and collagen type II) but increased collagen type I expression. Non‐methacrylated cartilage hydrogels did not promote chondrogenesis to a greater extent than either non‐methacrylated or methacrylated tendon hydrogels. Whereas methacrylated gelatin hydrogels supported relatively homogeneous increases in proteoglycan and collagen type II deposition throughout the construct over 42 days, ECM hydrogels possessed greater heterogeneity of staining intensity and construct morphology. These results do not support the utility of pepsin‐solubilized cartilage and tendon hydrogels for cartilage tissue engineering over methacrylated gelatin hydrogels. Methacrylation of tendon and cartilage ECM hydrogels permits thermal‐ and light‐induced polymerization but compromises chondrogenic differentiation of seeded MSCs.     

Human chondrocyte migration behaviour to guide the development of engineered cartilage

Tissue‐engineering techniques have been successful in developing cartilage‐like tissues in vitro using cells from animal sources. The successful translation of these strategies to the clinic will likely require cell expansion to achieve sufficient cell numbers. Using a two‐dimensional (2D) cell migration assay to first identify the passage at which chondrocytes exhibited their greatest chondrogenic potential, the objective of this study was to determine a more optimal culture medium for developing three‐dimensional (3D) cartilage‐like tissues using human cells. We evaluated combinations of commonly used growth factors that have been shown to promote chondrogenic growth and development. Human articular chondrocytes (AC) from osteoarthritic (OA) joints were cultured in 3D environments, either in pellets or encapsulated in agarose. The effect of growth factor supplementation was dependent on the environment, such that matrix deposition differed between the two culture systems. ACs in pellet culture were more responsive to bone morphogenetic protein (BMP2) alone or combinations containing BMP2 (i.e. BMP2 with PDGF or FGF). However, engineered cartilage development within agarose was better for constructs cultured with TGFβ3. These results with agarose and pellet culture studies set the stage for the development of conditions appropriate for culturing 3D functional engineered cartilage for eventual use in human therapies. Copyright © 2015 John Wiley & Sons, Ltd.     

Design and characterization of a tissue‐engineered bilayer scaffold for osteochondral tissue repair

Treatment of full‐thickness cartilage defects relies on osteochondral bilayer grafts, which mimic the microenvironment and structure of the two affected tissues: articular cartilage and subchondral bone. However, the integrity and stability of the grafts are hampered by the presence of a weak interphase, generated by the layering processes of scaffold manufacturing. We describe here the design and development of a bilayer monolithic osteochondral graft, avoiding delamination of the two distinct layers but preserving the cues for selective generation of cartilage and bone. A highly porous polycaprolactone‐based graft was obtained by combining solvent casting/particulate leaching techniques. Pore structure and interconnections were designed to favour in vivo vascularization only at the bony layer. Hydroxyapatite granules were added as bioactive signals at the site of bone regeneration. Unconfined compressive tests displayed optimal elastic properties and low residual deformation of the graft after unloading (< 3%). The structural integrity of the graft was successfully validated by tension fracture tests, revealing high resistance to delamination, since fractures were never displayed at the interface of the layers (n = 8). Ectopic implantation of grafts in nude mice, after seeding with bovine trabecular bone‐derived mesenchymal stem cells and bovine articular chondrocytes, resulted in thick areas of mature bone surrounding ceramic granules within the bony layer, and a cartilaginous alcianophilic matrix in the chondral layer. Vascularization was mostly observed in the bony layer, with a statistically significant higher blood vessel density and mean area. Thus, the easily generated osteochondral scaffolds, since they are mechanically and biologically functional, are suitable for tissue‐engineering applications for cartilage repair. Copyright © 2012 John Wiley & Sons, Ltd.     

Bio‐inspired design of a magnetically active trilayered scaffold for cartilage tissue engineering

An important topic in cartilage tissue engineering is the development of biomimetic scaffolds which mimic the depth‐dependent material properties of the native tissue. We describe an advanced trilayered nanocomposite hydrogel (ferrogel) with a gradient in compressive modulus from the top to the bottom layers (p < 0.05) of the construct. Further, the scaffold was able to respond to remote external stimulation, exhibiting an elastic, depth‐dependent strain gradient. When bovine chondrocytes were seeded into the ferrogels and cultured for up to 14 days, there was good cell viability and a biochemical gradient was measured with sulphated glycosaminoglycan increasing with depth from the surface. This novel construct provides tremendous scope for tailoring location‐specific cartilage replacement tissue; by varying the density of magnetic nanoparticles, concentration of base hydrogel and number of cells, physiologically relevant depth‐dependent gradients may be attained. © 2015 The Authors Journal of Tissue Engineering and Regenerative Medicine Published by John Wiley & Sons Ltd.     

A comparison study of different decellularization treatments on bovine articular cartilage

Previous researches have emphasized on suitability of decellularized tissues for regenerative applications. The decellularization of cartilage tissue has always been a challenge as the final product must be balanced in both immunogenic residue and mechanical properties. This study was designed to compare and optimize the efficacy of the most common chemical decellularization treatments on articular cartilage. Freeze/thaw cycles, trypsin, ethylenediaminetetraacetic acid (EDTA), sodium dodecyl sulfate (SDS), and Triton‐X 100 were used at various concentrations and time durations for decellularization of bovine distal femoral joint cartilage samples. Histological staining, scanning electron microscopy, DNA quantification, compressive strength test, and Fourier‐transform infrared spectroscopy were performed for evaluation of the decellularized cartilage samples. Treatment with 0.05% trypsin/EDTA for 1 day followed by 3% SDS for 2 days and 3% Triton X‐100 for another 2 days resulted in significant reduction in DNA content and simultaneous maintenance of mechanical properties. Seeding the human adipose‐derived stem cells onto the decellularized cartilage confirmed its biocompatibility. According to our findings, an optimized physiochemical decellularization method can yield in a nonimmunogenic biomechanically compatible decellularized tissue for cartilage regeneration application.     

An additive manufacturing‐based PCL–alginate–chondrocyte bioprinted scaffold for cartilage tissue engineering

Regenerative medicine is targeted to improve, restore or replace damaged tissues or organs using a combination of cells, materials and growth factors. Both tissue engineering and developmental biology currently deal with the process of tissue self‐assembly and extracellular matrix (ECM) deposition. In this investigation, additive manufacturing (AM) with a multihead deposition system (MHDS) was used to fabricate three‐dimensional (3D) cell‐printed scaffolds using layer‐by‐layer (LBL) deposition of polycaprolactone (PCL) and chondrocyte cell‐encapsulated alginate hydrogel. Appropriate cell dispensing conditions and optimum alginate concentrations for maintaining cell viability were determined. In vitro cell‐based biochemical assays were performed to determine glycosaminoglycans (GAGs), DNA and total collagen contents from different PCL–alginate gel constructs. PCL–alginate gels containing transforming growth factor‐β (TGFβ) showed higher ECM formation. The 3D cell‐printed scaffolds of PCL–alginate gel were implanted in the dorsal subcutaneous spaces of female nude mice. Histochemical [Alcian blue and haematoxylin and eosin (H&E) staining] and immunohistochemical (type II collagen) analyses of the retrieved implants after 4 weeks revealed enhanced cartilage tissue and type II collagen fibril formation in the PCL–alginate gel (+TGFβ) hybrid scaffold. In conclusion, we present an innovative cell‐printed scaffold for cartilage regeneration fabricated by an advanced bioprinting technology. Copyright © 2013 John Wiley & Sons, Ltd.     

Establishment of an in vitro three‐dimensional model for cartilage damage in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease that leads to progressive joint destruction. To further understand the process of rheumatoid cartilage damage, an in vitro model consisting of an interactive tri‐culture of synovial fibroblasts (SFs), LPS‐stimulated macrophages and a primary chondrocyte‐based tissue‐engineered construct was established. The tissue‐engineered construct has a composition similar to that of human cartilage, which is rich in collagen type II and proteoglycans. Data generated from this model revealed that healthy chondrocytes were activated in the presence of SFs and macrophages. The activated chondrocytes subsequently displayed aberrant behaviours as seen in a disease state such as increased apoptosis, decreased gene expression for matrix components such as type II collagen and aggrecan, increased gene expression for tissue‐degrading enzymes (MMP‐1, ‐3, ‐13 and ADAMTS‐4, ‐5), and upregulation of inflammatory mediator gene expression (TNF‐α, IL‐1β, IL‐6 and IKBKB). Additionally, the inclusion of SFs and macrophages in the model enabled both cell types to more closely replicate an in vivo role in mediating cartilage destruction. This is evidenced by extensive matrix loss, detected in the model through immunostaining and biochemical analysis. Subsequent drug treatment with celecoxib has shown that the model was able to respond to the therapeutic effects of this drug by reversing cartilage damage. This study showed that the model was able to recapitulate certain pathological features of an RA cartilage. If properly validated, this model potentially can be used for screening new therapeutic drugs and strategies, thereby contributing to the improvement of anti‐rheumatic treatment. Copyright © 2017 John Wiley & Sons, Ltd.     

Enhanced treatment of articular cartilage defect of the knee by intra‐articular injection of Bcl‐xL‐engineered mesenchymal stem cells in rabbit model

Direct intra‐articular injection of mesenchymal stem cells (MSCs) has been proposed as a potential cell therapy for cartilage defects. This cell therapy relies on the survival of the implanted MSCs. However, the arduous local environment may limit cell viability after implantation, which would restrict the cells' regenerative capacity. Thus, it is necessary to reinforce the implanted cells against the unfavourable microenvironment in order to improve the efficacy of cell therapy. We examined whether the transduction of an anti‐apoptotic protein, Bcl‐xL, into MSCs could prevent cell death and improve the implantation efficiency of MSCs in a rabbit model. Our current findings demonstrate that the group treated with Bcl‐xL‐engineered MSCs could improve cartilage healing both morphologically and histologically when compared with the controls. These results suggest that intra‐articular injection of Bcl‐xL‐engineered MSCs is a potential non‐invasive therapeutic method for effectively treating cartilage defects of the knee. Copyright © 2009 John Wiley & Sons, Ltd.     

多孔素蛋白支架修复兔下颌骨临界性骨缺损

背景：丝素蛋白具有良好的生物相容性和可降解性。目的：观察多孔丝素蛋白支架原位修复兔下颌骨临界性骨缺损效果。方法：建立免双侧下颌骨临界性骨缺损模型,随机选取一侧缺损植入多孔丝素蛋白支架作为实验组,另一侧缺损不作处理作为对照组。结果与结论：①大体标本：术后12周,实验组骨缺损腔表面完全被新生骨覆盖,材料无脱出;对照组骨缺损腔内充满肉芽组织,骨不连。②×射线骨密度测定：术后2,6,12周,两组骨密度均随着时间延长逐渐增高,组内不同时间点间差异有显著性意义（P〈0．05）,且同期实验组高于对照组（P〈0．05）。③组织病理切片苏木精伊红染色：术后12周,实验组岛状新生骨及骨小梁明显增多,而且粗大而致密,材料内部明显疏松,部分区域塌陷;对照组宿主骨边缘可见散在分布的新生骨组织,但并无粗大骨小梁形成。④骨形态发生蛋白2免疫组织化学染色：术后2,6,12周,两组骨形态发生蛋白2阳性细胞数均随着时间延长逐渐增多,组内不同时间点间差异有显著性意义（P〈0.05）,且同期实验组多于对照组（P〈0．05）。表明多孔丝素蛋白支架用于原位组织工程修复骨缺损具有一定可行性。     

Chondrocytes from congenital microtia possess an inferior capacity for in vivo cartilage regeneration to healthy ear chondrocytes

The remnant auricular cartilage from microtia has become a valuable cell source for ear regeneration. It is important to clarify the issue of whether the genetically defective microtia chondrocytes could engineer cartilage tissue comparable to healthy ear chondrocytes. In the current study, the histology and cell yield of native microtia and normal ear cartilage were investigated, and the biological characteristics of derived chondrocytes examined, including proliferation, chondrogenic phenotype and cell migration. Furthermore, the in vivo cartilage‐forming capacity of passaged microtia and normal auricular chondrocytes were systematically compared by seeding them onto polyglycolic acid/polylactic acid scaffold to generate tissue engineered cartilage in nude mice. Through histological examinations and quantitative analysis of glycosaminoglycan, Young's modulus, and the expression of cartilage‐related genes, it was found that microtia chondrocytes had a slower dedifferentiation rate with the decreased expression of stemness‐related genes, and weaker migration ability than normal ear chondrocytes, and the microtia chondrocytes‐engineered cartilage was biochemically and biomechanically inferior to that constructed using normal ear chondrocytes. This study provides valuable information for the clinical application of the chondrocytes derived from congenital microtia to engineer cartilage. Copyright © 2016 John Wiley & Sons, Ltd.