应用同种异体组织工程软骨修复关节软骨缺损观察

目的用胶原蛋白和人血纤维蛋白混合物为载体支架在体外进行软骨细胞三维立体培养,构建人工软骨组织,利用此人工软骨修复关节软骨缺损。方法取2周龄兔关节软骨,经消化、分离的软骨细胞体外培养。培养第3周时,进行免疫组织化学分析;利用培养3周的人工软骨对异体成兔的关节软骨损伤进行修复。结果培养物内软骨细胞均得到较好存活,形成软骨陷窝,出现同源性细胞簇,分泌软骨基质;DNA和糖胺多糖(GAG)在培养第24天时达到高峰,分别为(5.18±0.19)、(214.3±2.8)μg/块;对异体关节软骨损伤的移植修复结果良好,在12周时,移植物与周边正常组织结合紧密、齐高,移植的软骨细胞趋于柱状排列,为透明软骨组织。结论用胶原蛋白和人血纤维蛋白为载体支架体外培养软骨细胞,可构建较大的组织工程软骨,能较好地修复同种异体关节软骨缺损。     

应用人胚软骨细胞修复关节软骨缺损的研究

目的了解应用人胚胎关节软骨细胞修复家兔膝关节软骨大面积深层缺损的效果,为临床上进一步应用人胚胎关节软骨细胞进行同种异体细胞移植的可行性提供佐证.方法将分离的人胚胎关节软骨细胞以天然胶原作为细胞外基质网架,进行体外三维培养1周后,植入家兔关节软骨大面积深层(5 mm×5 mm×4 mm)缺损处,对修复组织进行大体观察及组织学评估.结果移植术后12周,缺损部位平坦、光滑,已为类似关节软骨的半透明组织填充,修复组织与宿主关节软骨组织整合较好,界限模糊;移植术后24周,缺损表面为透明软骨填充,缺损深部的软骨下骨组织已经重建.结论人胚胎关节软骨细胞可以作为软骨组织工程的种子细胞用于修复关节软骨组织的缺损.     

体外重建组织工程关节软骨的实验研究

目的　用胶原蛋白和人血纤维蛋白混合物为载体在体外进行软骨细胞三维立体培养 ,构建人工软骨组织。方法　取 2周龄的新生兔关节软骨 ,经消化 ,将获得的软骨细胞与牛 型胶原、人血冻干纤维蛋白原、凝血酶按一定比例混合 ,制成软骨培养物并在体外培养。培养第 3周时 ,取材进行 HE、甲苯胺蓝染色和透射电镜检查。结果　体外培养 3周 ,培养物内细胞均存活 ,形成软骨陷窝 ,同源性细胞簇出现 ,并分泌软骨基质。透射电镜下可见丰富的粗面内质网和线粒体 ,及少量的高尔基复合体。结论　用胶原蛋白和人血纤维蛋白为载体支架体外培养软骨细胞 ,可构建较大的组织工程软骨     

松质骨骨基质明胶负载软骨细胞移植修复兔膝关节软骨缺损

目的 应用松质骨骨基质明胶(bone matrix gelatin，BMG)负载兔软骨细胞移植修复同种异体关节软骨缺损。方法 BMG载软骨细胞，体外培养12d后植入同种异体新西兰兔膝关节软骨缺损。对照组植入BMG或不作任何植入。移植前用胰蛋白酶处理关节软骨缺损。术后2、4、8、12、24周行解剖显微镜、组织学、电镜观察和免疫组织化学染色。结果 BMG术后8周降解。实验组术后24周关节软骨缺损以软骨组织修复，与周围软骨及软骨下骨愈合良好。Safranin-O、免疫组织化学染色证实其基质有蛋白多糖和Ⅱ型胶原，电镜观察表明修复组织软骨细胞及基质与正常关节软骨一致。BMG对照组以部分软骨组织修复，空白对照组以纤维组织修复。结论 松质骨BMG可作为软骨组织工程的天然细胞支架，其负载软骨细胞移植能修复同种异体兔关节软骨缺损。     

应用自体软骨细胞移植物修复关节软骨缺损

目的 通过体外扩增关节软骨细胞，构建软骨组织工程移植物，观察移植物对自体关节软骨损伤的修复作用。方法 由8周龄成年兔髌骨外侧缘获取关节软骨，分离软骨细胞，体外扩增后，与牛Ⅰ型胶原、人血冻干纤维蛋白原、凝血酶按一定比例混合，制成软骨培养物，体外培养4d。用于对成兔自体关节软骨损伤的移植修复。结果 成年家兔关节软骨细胞体外单层培养至第2代时开始出现去分化现象，可利用生长因子抑制去分化；该移植物的移植修复效果良好，修复后12周移植物与周边正常组织结合紧密、齐高，细胞趋于柱状排列，已形成透明软骨组织。结论 利用体外扩增的方法能获得足够量表型良好的关节软骨细胞，当应用胶原-纤维蛋白为载体制备出软骨组织工程培养物后，能较好地修复自体关节软骨损伤。     

组织工程软骨修复兔膝关节软骨大面积深层缺损的实验研究

目的　将培养的软骨细胞埋在胶原凝胶中,观察其对家兔漆关节软骨大面积深层缺损的修复作用。方法体外培养软骨细胞,然后与胶原以一定比例混合培养,植入免膝关节股骨负重面的缺损（５ｍｍ ×４ｍｍ）部位,观察 ２、４、８．１２周软骨缺损的修复情况,并进行大体和组织学观察。结果移植后第 ８周,所修复组织的边缘变得模糊,与周围宿主整合得很好,缺损边缘不清晰。组织学观察,缺损处表面光滑,边缘与宿主完全整合,缺损处呈典型的关节软骨样组织,并且底部有新形成的软骨及骨小梁生成。对照组（未移植组）组织学观察缺损部位主要为纤维组织所填充,未见有由新生软骨细胞形成的软骨组织。结论埋在胶原凝胶中软骨细胞对家兔膝关节软骨深层缺损的修复作用。     

组织工程软骨修复全层大面积关节软骨损伤的实验研究

目的观察由软骨细胞体外培养的人工软骨组织对家兔膝关节软骨全层缺损修复的可行性.方法分离收集兔软骨细胞(4周龄),用培养液悬浮,经离心管体外培养成组织工程软骨,然后植入兔膝关节股骨负重面的缺损(5 mm×4 mm)部位,观察2,4,8,12周软骨缺损的修复情况,并进行大体和组织学观察.结果移植后第8周,移植部位填充物与宿主已完全整合,缺损处表面光滑;组织学显示,缺损部位新生软骨与所移植软骨有较好的连续性,并且缺损底部有软骨下骨及海绵状骨生成;对照组(未移植组),从组织学观察到缺损部位呈纤维样修复,未见有由新生软骨细胞形成软骨组织.结论用体外培养的组织工程软骨做移植物修复家兔关节软骨组织深层缺损具有较好的疗效.     

β-TCP—HA—AC—BMSCs复合体修复兔膝关节骨、软骨缺损的实验研究

目的观察磷酸三钙人工骨（β-TCP）－透明质酸（HA）－脱细胞耳软骨（AC）-骨髓间充质干细胞（BM-SCs）复合体修复兔膝关节骨、软骨缺损的效果。方法获取新西兰大白兔BMSCs,体外诱导成软骨细胞并培养,取异体兔耳软骨并进行脱细胞处理,并与β-TCP—AC结合形成复合物接种软骨细胞。取6月龄新西兰大白兔12只,手术制备膝关节缺损模型,并随机分为A、B两组。A组（8只）缺损区植入β-TCP—AC—BMSCs,并于关节腔内注入HA;B组（4只）缺损空置作为空白对照。结果BMSCs在体外生长稳定,增殖能力强,可被诱导为软骨细胞。第16周,A组缺损区内充填白色半透明新生软骨组织,色泽与正常软骨相似,质韧,表面平整,与正常软骨界限消失,表面细胞平行于关节面,深层细胞排列紊乱,细胞呈团状,基质异染广泛,与周围正常软骨连接良好。B组缺损区未修复,底部为白色纤维组织。结论 β-TCP—HA-AC—BMSCs复合体修复兔膝关节骨、软骨缺损效果良好。     

柔肝中药对体外培养软骨细胞增殖能力及关节软骨低聚基质蛋白分泌的影响

目的 探讨柔肝中药对体外培养软骨细胞增殖能力及关节软骨低聚基质蛋白（COMP）分泌的影响。方法 采用分阶段酶消化法体外培养兔软骨细胞，以2×10^4／ml密度接种3代内细胞，以Ⅱ型胶原的免疫组织化学研究鉴定细胞。给予家兔临床等效剂量灌胃后，抽取含药血清培养细胞，分别用5％、10％的柔肝方含药血清（分给药后1、3、5h3个时间点）以及正常兔血清、小牛血清干预7d，采用四甲基偶氮唑蓝（MTF）法观察中药含药血清对体外培养的软骨细胞增殖的影响；体外培养人软骨细胞，采用柔肝复方组及单味柔肝药提取物直接添加体外培养体系3d，添加终浓度为10mg／ml。采用酶联免疫吸附试验（ELISA）检测药物对体外培养的人软骨细胞COMP分泌的影响。结果 培养细胞经Ⅱ型胶原的免疫组织化学染色后有阳性表现，在对软骨细胞增殖的影响方面，柔肝方含药血清各组均优于兔血清组和小牛血清组，其中含药血清组的3h时间点总体优于1h及5h时间点（P〈0．05）；在对软骨细胞上清COMP分泌方面，柔肝复方及单方提取物组均有促进细胞分泌COMP的作用（P〈0．05），但两组之间差异无统计学意义（P〉0．05）。结论 柔肝方中药含药血清可以促进体外培养软骨细胞增殖；在药物直接干预的条件下，柔肝复方及单方提取物可以促进软骨细胞分泌COMP。     

人胚胎关节软骨细胞库的建立

目的：体外建立人胚胎关节软骨细胞冻存、复苏的稳定技术，为软骨组织工程提供大量的、具有软骨细胞生物活性的种子细胞。方法：将传代培养的人胚胎关节软骨细胞用含10%DMSO、50%胎牛血清的IMDM培养液悬浮后，置于-196℃的液氮中长期保存，建立人胚胎关节软骨细胞库。然后将细胞库中的冻存细胞进行复苏培养，观察其生长状况，并测定软骨细胞中DNA及糖醛酸的含量。结果：冻存软骨细胞复苏后仍保持旺盛的增殖与分泌细胞外基质的功能。结论：关节软骨细胞库的建立，可以长期保存培养的软骨细胞。     

Joint cartilage regeneration by tissue engineering

Summary The research field of tissue engineering combines cells biology, biomaterial science, and surgery. Major long-term goals are tissue and organ replacement therapies using the patients‘ own cells. Our work is focused on the treatment of severe joint defects and on plastic surgery using in vitro engineered cartilage tissues. The practical approaches in cartilage engineering face problems with three-dimensional cell distribution or cell immobilization raising biocompatibility problems. The tissue engineering of cartilage is based on combining biocompatible cell embedding substances such as fibrin, agarose, alginate, hyaluronic acid and fiber fleece scaffolds of poly α-hydroxy acids (PLLA/PGLA). Different technical approaches were established: a) three-dimensional in vitro cultures of chondrocytes for the development of vital tissue transplants and b) interacting three-dimensional cultures consisting of different cell populations, such as BMP-transfected mesenchymal cells. The preshaped artificial tissue constructs were cultured in perfusion chambers to maintain a stable diffusion of nutrients during the in vitro pre-formation step. Subsequently, pre-formed tissues were implanted into nude mice and into 4mm articular joint defects of rabbits. Transplants were found to produce cartilage typic morphological patterns and matrix. 80% of the transplants remained stable in vivo. However, 20% of the tissues are resorbed or replaced by a fibrous tissue. These results demonstrate that current artificial cartilage transplants are already feasible for plastic reconstruction. The treatment of severe joint defects, however, faces additional problems which are addressed in ongoing studies: (a) the fixation of engineered cartilage in joints, (b) the protection against chronic inflammatory degradation, and (c) the required enormous mechanical stability      

Joint cartilage regeneration by tissue engineering

The research field of tissue engineering combines cells biology, biomaterial science, and surgery. Major long-term goals are tissue and organ replacement therapies using the patients‘ own cells. Our work is focused on the treatment of severe joint defects and on plastic surgery using in vitro engineered cartilage tissues. The practical approaches in cartilage engineering face problems with three-dimensional cell distribution or cell immobilization raising biocompatibility problems. The tissue engineering of cartilage is based on combining biocompatible cell embedding substances such as fibrin, agarose, alginate, hyaluronic acid and fiber fleece scaffolds of poly α-hydroxy acids (PLLA/PGLA). Different technical approaches were established: a) three-dimensional in vitro cultures of chondrocytes for the development of vital tissue transplants and b) interacting three-dimensional cultures consisting of different cell populations, such as BMP-transfected mesenchymal cells. The preshaped artificial tissue constructs were cultured in perfusion chambers to maintain a stable diffusion of nutrients during the in vitro pre-formation step. Subsequently, pre-formed tissues were implanted into nude mice and into 4mm articular joint defects of rabbits. Transplants were found to produce cartilage typic morphological patterns and matrix. 80% of the transplants remained stable in vivo. However, 20% of the tissues are resorbed or replaced by a fibrous tissue. These results demonstrate that current artificial cartilage transplants are already feasible for plastic reconstruction. The treatment of severe joint defects, however, faces additional problems which are addressed in ongoing studies: (a) the fixation of engineered cartilage in joints, (b) the protection against chronic inflammatory degradation, and (c) the required enormous mechanical stability     

Technology Insight: adult stem cells in cartilage regeneration and tissue engineering

Articular cartilage, the load-bearing tissue of the joint, has limited repair and regeneration potential. The scarcity of treatment modalities for large chondral defects has motivated attempts to engineer cartilage tissue constructs that can meet the functional demands of this tissue in vivo. Cartilage tissue engineering requires three components: cells, scaffold, and environment. Adult stem cells, specifically multipotent mesenchymal stem cells, are considered the cell type of choice for tissue engineering, because of the ease with which they can be isolated and expanded and their multilineage differentiation capabilities. Successful outcome of cell-based cartilage tissue engineering ultimately depends on the proper differentiation of stem cells into chondrocytes and the assembly of the appropriate cartilaginous matrix to achieve the load-bearing capabilities of the natural articular cartilage. Multiple requirements, including growth factors, signaling molecules, and physical influences, need to be met. Adult mesenchymal stem-cell-based tissue engineering is a promising technology for the development of a transplantable cartilage replacement to improve joint function.     

氨基葡萄糖对体外培养人软骨和滑膜细胞软骨寡聚基质蛋白分泌影响的比较

目的 比较氨基葡萄糖对体外培养软骨和滑膜细胞软骨寡聚基质蛋白(COMP)分泌的影响.方法 软骨细胞和滑膜细胞采自骨关节炎(OA)患者,采用分阶段酶消化法体外培养人软骨细胞和滑膜细胞,给予实验兔以氨基葡萄糖临床等效剂量灌胃后,抽取含药血清培养细胞.采用酶联免疫吸附试验(ELISA)检测药物对体外培养的人软骨细胞和滑膜细胞培养上清液中COMP的浓度.结果 体外培养滑膜细胞分泌的COMP浓度[(41.6±0.4)ng/ml]显著高于软骨细胞[(5.5±3.0)ng/ml](19＜0.05).氨基葡萄糖可显著增加体外培养软骨细胞的COMP分泌[(20.3±3.6)与(5.5±3.0)ng/ml,P＜0.05];而对体外培养滑膜细胞的作用较弱,可轻度减少COMP分泌[(36.6±1.3)与(41.6±0.4)ng/ml].结论 氨基葡萄糖含药血清可以促进体外培养软骨细胞分泌COMP,而对体外培养滑膜细胞无明显作用.     

Interleukin 17 induced nitric oxide suppresses matrix synthesis and protects cartilage from matrix breakdown

OBJECTIVE: To investigate the role of nitric oxide (NO) in basal and cytokine induced cartilage matrix breakdown and synthesis across different species and in chondrocytes cultured as isolated cells or as tissue explants. METHODS: Articular cartilage from bovine, porcine, or human joints was cultured as explants in serum-free media. Explants or monolayer cultures of primary chondrocytes were treated with cytokines in the absence or presence of inhibitors [antibodies to leukemia inhibitory factor (anti-LIF) or tumor necrosis factor-alpha, dexamethasone, or inhibitors of aggrecanase or NO synthase]. NO production and matrix breakdown and synthesis were measured. RESULTS: At low concentrations, a novel interleukin 17 (IL-17) family member induced matrix breakdown without altering NO production. Treatment of articular cartilage explants with dexamethasone or anti-LIF blocked NO production by IL-17, but not by IL-1alpha. Inhibition of NO production in cytokine treated cartilage explants enhanced matrix breakdown and partially overcame suppression of matrix synthesis. In isolated chondrocytes, inhibition of NO production decreased expression of gelatinase and increased expression of stromelysin. CONCLUSION: Endogenous NO serves a dual function in cartilage: to protect the tissue from matrix breakdown and to mediate suppression of proteoglycan synthesis by cytokines. Despite the similarities in biological function between IL-I and IL-17, their downstream signaling pathways are distinct and appear to be affected by extracellular matrix degradation.     

Articular cartilage repair using dedifferentiated articular chondrocytes and bone morphogenetic protein 4 in a rabbit model of articular cartilage defects

OBJECTIVE: To observe redifferentiation of dedifferentiated chondrocytes after transplantation into the joint, and to evaluate the ability of dedifferentiated chondrocytes transduced with adenovirus containing bone morphogenetic protein 4 (BMP-4) to redifferentiate in vitro and in vivo in a rabbit model of articular cartilage defects. METHODS: Monolayer and pellet culture systems were used to evaluate the redifferentiation of dedifferentiated chondrocytes transduced with BMP-4. A rabbit model of partial-thickness articular cartilage defects was used to evaluate cartilage repair macroscopically and histologically, 6 and 12 weeks after transplantation with first-passage, fifth-passage, or transduced fifth-passage chondrocytes. Histologic grading of the repaired tissue was performed. Expression of BMP-4 and the ability of transplanted cells to recover a chondrocytic phenotype were also assessed. RESULTS: BMP-4--expressing dedifferentiated chondrocytes recovered a chondrocytic phenotype in vitro. After transplantation into the joint, some of the dedifferentiated chondrocytes in the defect sites could undergo redifferentiation and formed matrix that displayed positive toluidine blue staining for glycosaminoglycans. Histologic scores of the regenerative tissue revealed significantly better cartilage repair in rabbits transplanted with BMP-4--expressing cells than in the other treatment groups. Staining with toluidine blue revealed expression of BMP-4 in the cells and in the matrix surrounding the cells. CONCLUSION: Some dedifferentiated chondrocytes can redifferentiate after transplantation into the load-bearing joint. BMP-4 can be used to induce redifferentiation of dedifferentiated chondrocytes in vitro and in vivo, which could help enhance articular cartilage repair.     

Adhesion of transplanted chondrocytes onto cartilage in vitro and in vivo

OBJECTIVE: The specific objectives of this study using organ culture were (1) to transplant chondrocytes onto an intact cartilage surface; (2) to genetically modify endogenous and transplanted chondrocytes; and (3) to assess the ability of these cells to continually express a gene product. The specific objective with in vivo experiments was to transplant chondrocytes with intraarticular injections to cartilage. METHODS: Fluorescent membrane and intracellular dyes were used in conjunction with confocal microscopy to observe the integration of transplanted chondrocytes into cartilage both in vitro and in vivo. The distribution and duration of binding of rat, canine, and bovine chondrocytes to cartilage explants and the duration of expression of genes transduced into the transplanted chondrocytes were also determined. We used the vector AdlacZ, an E1 and E3 deleted replication defective adenoviral vector that contains the beta-galactosidase gene driven by the beta-actin promoter and the cytomegalovirus enhancer. RESULTS: The transplanted chondrocytes had a patchy distribution after in vitro or in vivo transplantation and buried themselves within the cartilage over time. Chondrocytes infected with the adenoviral vector AdlacZ soon or well after transplant to cartilage explants were maintained on the cartilage and continued throughout the duration of each trial to produce beta-galactosidase coded by the adenoviral vector. The cartilage plugs were infected with AdlacZ at 2 days or one, 2, 5, or 8 weeks after the chondrocytes were transplanted. The cartilage slices were then cultured from 15 days for chondrocytes infected at 8 weeks to 60 days for chondrocytes infected at 2 days post-transplant before determining the expression of beta-galactosidase. CONCLUSION: These results support the possibility of repairing cartilage by intraarticular injections of chondrocytes. Transduction of chondrocytes with genes producing a variety of matrix promoting proteins should further enhance the reconstruction of osteoarthritic cartilage.     

The superficial layer of human articular cartilage is more susceptible to interleukin-1–induced damage than the deeper layers

Objective. To compare the responses of chondrocytes from superficial and deep layers of normal human articular cartilage to interleukin-1 (IL-1) and IL-1 receptor antagonist protein (IRAP), and to evaluate the binding sites for IL-1 on these cells. Methods. Cartilage and chondrocytes from superficial and deeper layers of human femoral condyles were cultured with and without IL-1 in the presence and absence of IRAP. The effect of these agents on ³⁵S-proteoglycan synthesis and catabolism and production of stromelysin and tissue inhibitor of metalloproteinases 1 (TIMP-1) were measured by biochemical and immunologic assays. Receptor binding was evaluated using ¹²⁵I-labeled IL-1. Results. IL-1 induced more severe inhibition of proteoglycan synthesis and a lower ratio of secreted TIMP-1:stromelysin in chondrocytes from superficial cartilage than those from deeper cartilage. IRAP blocked responses to IL-1 more effectively in chondrocytes from deep cartilage than those from superficial cartilage. Chondrocytes from the articular surface showed approximately twice the number of high-affinity binding sites for IL-1 as did cells from deep cartilage. Conclusion. Chondrocytes from the surface of articular cartilage show a greater vulnerability to the harmful effects of IL-1 and are less responsive to the potential therapeutic effects of IRAP than cells in the deeper layers of the tissue.