体外诱导人骨髓间充质干细胞分化为软骨细胞的研究

目的：探讨胰岛素样生长因子-Ⅰ（IGF-Ⅰ）和软骨细胞培养液体外诱导骨髓间充质干细胞（MSCs）向软骨细胞分化的可能性。方法：采用Percoll分离液分离培养人胚MSCs，体外扩增，用流式细胞仪测定MSCs的CD44、CD71、CD34、CD45表达；在第4代MSCs中加入的条件培养基进行诱导，根据条件培养基的不同分为4组：①IGF-Ⅰ组：培养基中加入100ng／mL IGF-Ⅰ；②软骨细胞培养液组：加入软骨细胞培养液；③联合诱导组：培养液中加入100ng／mL IGF-Ⅰ和软骨细胞培养液；④对照组：培养基中不加入IGF-Ⅰ和软骨细胞培养液。采用倒置显微镜观察、Ⅱ型胶原免疫组化、细胞内蛋白多糖（PG）含量测定等方法判断诱导细胞的形态变化和表达软骨基质的能力。结果：体外培养的MSCs呈现成纤维细胞样形态，流式细胞仪检测结果显示，MSCs阳性表达CD44，阴性表达CD34，CD45；IGF-Ⅰ和软骨细胞培养液联合诱导15d后，MSCs开始呈现软骨细胞的形态特点，Ⅱ型胶原免疫组化呈阳性，而未诱导的MSCs组呈阴性；联合诱导组细胞内PG含量为8．92μg／ml，显著高于IGF-Ⅰ组、软骨细胞培养液组和对照组，但低于正常软骨细胞（P〈0．01）。结论：IGF-Ⅰ和软骨细胞培养液能诱导MSCs向软骨细胞分化。     

与软骨细胞共培养和条件培养液诱导骨髓间充质干细胞向软骨细胞分化的比较

背景：骨髓间充质干细胞体外转化很大程度上依赖于合适的培养条件。 目的：比较与软骨细胞共培养和条件培养液2种不同的诱导方案诱导骨髓间充质干细胞向软骨细胞分化的特点。 方法：分离培养大鼠骨髓间充质干细胞和耳软骨细胞,采用骨髓间充质干细胞与软骨细胞共培养及条件培养液诱导成软骨的方法,诱导骨髓间充质干细胞向软骨细胞分化。以MTT法及流式细胞仪检测细胞活性及周期,糖胺多糖、甲苯胺蓝以及免疫组化染色检测细胞生物学特性,以RT-PCR法检测诱导后的软骨细胞Ⅱ型胶原RNA表达情况。 结果与结论：采用共培养方式诱导的软骨细胞,其生物学特性与采用条件培养液诱导的软骨细胞相比,前者优于后者,如分泌糖胺多糖的能力以及基质分泌量均较高。提示共培养方式诱导的软骨细胞更接近正常软骨细胞,更有利于作为组织工程软骨的种子细胞。     

HO-1修饰的大鼠骨髓间充质干细胞在体外对淋巴细胞的影响北大核心CSCD

目的：探讨血红素加氧酶1（HO-1）修饰的大鼠骨髓间充质干细胞（BM MSCs）在体外对淋巴细胞的免疫调节作用。方法体外分离培养和鉴定BM MSCs ,用载有HO-1基因的重组腺病毒载体进行感染,形成HO-1/BM MSCs,与大鼠脾淋巴细胞共培养。 MTT法检测淋巴细胞的增殖活性,碘化丙啶染色流式细胞术分析细胞周期的分布情况,ELISA法检测细胞因子含量,流式细胞仪分析T淋巴细胞CD25、CD71的表达。结果 HO-1/BM MSCs参与共培养的淋巴细胞的增殖活性和细胞周期进程均被抑制、促炎因子（ IL-2、TNF-α和IFN-γ）的分泌量降低、抗炎因子（ IL-10）的分泌量升高、T淋巴细胞CD25和CD71的表达降低,与BM MSCs组相比差异有统计学意义。结论 HO-1/BM MSCs较BM MSCs能够更好地发挥对淋巴细胞的免疫调节作用。     

骨髓基质干细胞与软骨细胞体外共培养向软骨细胞转化的实验研究

目的 探讨骨髓基质干细胞（BMSCs）与软骨细胞体外共培养成软骨的可行性,以及能有效促进BMSCs的软骨向分化混合培养的比例.方法 以全骨髓法及梯度密度离心法分离幼兔BMSCs、梯度密度离心法分离软骨细胞,并分别对这2种细胞进行培养、扩传,将P2 BMSCs与P3软骨细胞进行体外共培养,分为：BMSCs/软骨细胞为2/1及4/1的2个共培养组,软骨细胞组,BMSCs组,分别于第1,3,5,7,9 d以MTT法检测细胞的增殖情况;分别于第1、2、3周对4组的细胞进行甲苯胺蓝染色及以RT-PCR方法检测蛋白多糖和Ⅱ型胶原表达的变化.结果 2种分离培养方法所得BMSCs及软骨细胞增殖旺盛,细胞形态正常,各组增殖情况良好,1,3,5,7,9 d时各组之间的差异具有统计学意义（P＜0.05）,但2/1与4/1共培养组之间无显著性差异;2/1及4/1共培养组在3周时以软骨样细胞为主,细胞呈均一异染,细胞被染成紫色,核仁染成深蓝色;蛋白多糖及Ⅱ型胶原基因表达：在1,2,3周时各组之间的差异具有统计学意义（P＜0.05）,共培养组和软骨细胞组3组之间蛋白多糖及Ⅱ型胶原表达水平无显著性差异,且均与BMSCs组之间有显著性差异,具有统计学意义（P＜0.05）.结论 将BMSCs与软骨细胞体外共培养,可以被有效地诱导为软骨细胞,软骨微环境在BMSCs分化为软骨细胞的过程中起到了很重要的作用.     

不同剂量骨碎补对兔骨髓间充质干细胞增殖分化的影响

背景:现代研究表明骨碎补具有推迟细胞退行性变、降低骨关节病发病率的作用。目的:比较不同剂量骨碎补冻干粉诱导兔骨髓间充质干细胞增殖、分化的效果,并筛选出最佳剂量。方法:利用密度梯度离心法结合贴壁筛选法分离培养兔骨髓间充质干细胞,分为空白组、转化生长因子β1阳性对照组、骨碎补高、中、低剂量组(分别含骨碎补0.4 mg,0.1 mg,5μg),取第3代骨髓间充质干细胞,根据实验分组加入不同培养液进行培养,1周后MTT比色法检测活细胞数目,免疫组化法测定Ⅱ型胶原表达。结果与结论:MTT比色结果显示转化生长因子β1和骨碎补冻干粉均能促进骨髓间充质干细胞增殖,转化生长因子β1阳性对照组骨碎补低剂量组骨碎补中剂量组骨碎补高剂量组空白组。细胞免疫组化检测Ⅱ型胶原结果显示转化生长因子β1和骨碎补冻干粉均可以诱导兔骨髓间充质干细胞向软骨细胞分化,诱导后的细胞明显表达Ⅱ型胶原,转化生长因子β1阳性对照组骨碎补低剂量组骨碎补中剂量组骨碎补高剂量组空白组。结果表明骨碎补能促进兔骨髓间充质干细胞增殖和分化,尤以5μg剂量效果最佳。     

京尼平苷对大鼠软骨细胞增殖的影响

背景：京尼平苷能够促进韧带成纤维细胞的增殖和胶原的合成,促进组织的修复和韧带损伤的愈合。 目的：观察京尼平苷对大鼠软骨细胞增殖的影响。 方法：采用二次酶消化法获得大鼠关节软骨细胞进行传代培养,并取第4代细胞给予0,25,50,100 mmol/L京尼平苷干预,利用MTT比色、流式细胞仪检测细胞周期等方法检测药物干预后第4代软骨细胞的增殖情况。 结果与结论：体外培养的软骨细胞随着传代次数的增加,细胞形态由原代的多角形逐渐变为长梭形;且随着培养时间的延长及京尼平苷浓度的升高,软骨细胞增殖更为显著(P < 0.01)。     

去卵巢对SD大鼠MSCs生物学特性的影响

目的:通过比较正常与双侧卵巢切除法复制的骨质疏松症(OP)模型大鼠骨髓间充质干细胞(MSCs)的形态学、生长曲线及细胞周期的差异,观察去卵巢对SD大鼠MSCs生物学特性的影响。方法:20只10月龄SD大鼠随机分成模型组和假手术组,每组10只;以双侧卵巢切除法复制OP模型;造模12周后,采用全骨髓贴壁法提取正常和OP大鼠MSCs;差速贴壁原理纯化MSCs;分别采用倒置相差显微镜、透射电子显微镜(TEM)、扫描电子显微镜(SEM)观察并比较正常与OP大鼠MSCs的形态学差异;MTT法检测正常与OP大鼠MSCs生长曲线;流式细胞仪检测正常与OP大鼠MSCs细胞周期。结果:OP大鼠MSCs细胞形态变得宽大、扁平,细胞内部细胞器减少,细胞活力下降,并有向脂肪细胞分化的现象发生;与正常组比较,OP大鼠细胞的增殖能力下降。结论:去卵巢导致大鼠MSCs形态变得宽大、扁平,体外增殖能力下降。     

碱性成纤维细胞生长因子和5-氮杂胞苷对大鼠骨髓间充质干细胞分化潜能和细胞增殖的影响

目的:探讨碱性成纤维细胞生长因子(bFGF)和5-氮杂胞苷(5-aza)对体外骨髓间充质干细胞(MSCs)细胞增殖与分化潜能的影响。方法:大鼠骨髓中获得MSCs,培养传代,在倒置相差显微镜和透射电镜下观察细胞形态变化;流式细胞仪检测细胞周期改变;MTT法检测bFGF和5-aga对MSCs生长的影响;免疫细胞化学方法检测actin、desmin、myoglobin、NSE、GFAP的表达。结果:有心肌样细胞和神经元样细胞的形态变化;MSCs经5-aza以及5-aza加bFGF联合诱导actin、desmin、myoglobin、NSE和GFAP的表达均较对照组显著增高;而经bFGF诱导后,前4种蛋白表达无明显变化,仅GFAP蛋白表达显著增高。结论:5-aza对MSCs细胞生长有抑制作用,而bFGF有明显促增殖作用。MSCs被5-aza诱导分化成心肌样细胞和神经元样细胞,bFGF可使MSCs分化为GFAP阳性的神经胶质样细胞。     

用流式细胞仪检测鲨鱼软骨粉提取物对大鼠微血管内皮细胞的作用

目的研究鲨鱼软骨粉提取物对大鼠肺微血管内皮细胞的影响。方法用流式细胞仪（ＰＩ染色）测定体外培养的肺微血管内皮细胞中细胞周期和细胞凋亡的变化。结果体外培养的微血管内皮细胞与鲨鱼软骨粉全成分（ ６ｍｇ／ｍｌ）、成分 Ａ（０．０１ｍｇ／ｍｌ）、成分Ｂ（０．０１ｍｇ／ｍｌ）一起培养２４小时后经流式细胞仪检测发现,成分Ｂ使细胞周期中Ｇ_２－Ｍ期细胞明显减少（Ｐ＜０．０５）,成分Ａ使凋亡细胞明显增加（Ｐ＜０．０１）。结论成分Ｂ可能是鲨鱼软骨粉中的一种水溶性抑制成分,它对微血管内皮细胞的增殖起抑制作用,成分Ａ对细胞凋亡的作用,还有待于进一步研究。     

miR-30a-5p靶向SIRT1调控骨关节炎软骨细胞增殖和凋亡的研究

为研究miR-30a-5p对骨关节炎(osteoarthritis,OA)软骨细胞增殖和凋亡的影响并探讨其机制,运用实时荧光RT-PCR检测人原代OA软骨细胞及正常软骨细胞中miR-30a-5p、沉默信息调节因子2相关酶Ⅰ(silent information regulator 1, SIRT1)的表达。研究分为正常对照组(正常软骨细胞)、OA+anti-miR-NC组(转染anti-miR-NC)、OA+anti-miR-30a-5p组(转染anti-miR-30a-5p)、OA+pcDNA组(转染pcDNA)、OA+pcDNA-SIRT1组(转染pcDNA-SIRT1)、OA+anti-miR-30a-5p+si-NC组(anti-miR-30a-5p和si-NC共转染)、OA+anti-miR-30a-5p+si-SIRT1组(anti-miR-30a-5p和si-SIRT1共转染),用脂质体法进行细胞转染,Western blotting检测各组细胞中SIRT1的表达,MTT试验检测细胞的增殖能力,流式细胞术检测细胞的凋亡情况,双荧光素酶报告基因检测试验检测细胞的荧光活性。结果显示,与正常软骨细胞比较,OA软骨细胞中miR-30a-5p表达显著升高(P0.05),SIRT1表达显著降低(P0.05);抑制miR-30a-5p、过表达SIRT1均可促进OA软骨细胞增殖,抑制其凋亡。miR-30a-5p靶向SIRT1。敲减SIRT1表达可逆转抑制miR-30a-5p对OA软骨细胞的增殖促进和凋亡抑制作用。提示miR-30a-5p可促进OA软骨细胞增殖,抑制其凋亡,其机制可能与靶向SIRT1有关,这可为OA的靶向治疗提供依据。     

Effect of low oxygen tension on tissue-engineered cartilage construct development in the concentric cylinder bioreactor

Cartilage is exposed to low oxygen tension in vivo, suggesting culture in a low-oxygen environment as a strategy to enhance matrix deposition in tissue-engineered cartilage in vitro. To assess the effects of oxygen tension on cartilage matrix accumulation, porous polylactic acid constructs were dynamically seeded in a concentric cylinder bioreactor with bovine chondrocytes and cultured for 3 weeks at either 20 or 5% oxygen tension. Robust chondrocyte proliferation and matrix deposition were achieved. After 22 days in culture, constructs from bioreactors operated at either 20 or 5% oxygen saturation had similar chondrocyte densities and collagen content. During the first 12 days of culture, the matrix glycosaminoglycan (GAG) deposition rate was 19.5 x 10(-9) mg/cell per day at 5% oxygen tension and 65% greater than the matrix GAG deposition rate at 20% oxygen tension. After 22 days of bioreactor culture, constructs at 5% oxygen contained 4.5 +/- 0.3 mg of GAG per construct, nearly double the 2.5 +/- 0.2 mg of GAG per construct at 20% oxygen tension. These data demonstrate that culture in bioreactors at low oxygen tension favors the production and retention of GAG within cartilage matrix without adversely affecting chondrocyte proliferation or collagen deposition. Bioreactor studies such as these can identify conditions that enhance matrix accumulation and construct development for cartilage tissue engineering.     

A Collagen–Poly(Vinyl Alcohol) Nanofiber Scaffold for Cartilage Repair

Articular cartilage has a limited capacity for self-repair. Untreated injuries of cartilage may lead to osteoarthritis. This problem demands new effective methods to reconstruct articular cartilage. Mesenchymal stem cells (MSCs) have the proclivity to differentiate along multiple lineages giving rise to new bone, cartilage, muscle, or fat. This study was an animal model for autologous effects of transplantation of MSCs with a collagen–poly(vinyl alcohol) (PVA) scaffold into full-thickness osteochondral defects of the stifle joint in the rabbit as an animal model. A group of 10 rabbits had a defect created experimentally in the full thickness of articular cartilage penetrated into the subchondral space in the both stifle joints. The defect in the right stifle was filled with MSCs/collagen–PVA scaffold (group I), and in the left stifle, the defect was left without any treatment as the control group (group II). Specimens were harvested at 12 weeks after implantation, examined histologically for morphologic features, and stained immunohistochemically for type-II collagen. Histology observation showed that the MSCs/collagen–PVA repair group had better chondrocyte morphology, continuous subchondral bone, and much thicker newly formed cartilage compared with the control group at 12 weeks post operation. There was a significant difference in histological grading score between these two groups. The present study suggested that the hybrid collagen–PVA scaffold might serve as a new way to keep the differentiation of MSCs for enhancing cartilage repair.     

Cartilage regeneration using mesenchymal stem cells and a PLGA-gelatin/chondroitin/hyaluronate hybrid scaffold

The study was to produce a novel hybrid poly-(lactic-co-glycolic acid) (PLGA)-gelatin/chondroitin/hyaluronate (PLGA-GCH) scaffold and evaluate its potentials in cartilage repair. The porous PLGA-GCH scaffold was developed to mimic the natural extra cellular matrix of cartilage. The differentiated mesenchymal stem cells (MSCs) seeded on PLGA-GCH or PLGA scaffold were incubated in vitro and showed that, compared to PLGA scaffold, the PLGA-GCH scaffold significantly augmented the proliferation of MSCs and GAG synthesis. Then autologous differentiated MSCs/PLGA-GCH was implanted to repair full-thickness cartilage defect in rabbit, while MSCs/PLGA for the contra lateral cartilage defect (n=30). Fifteen additional rabbits without treatment for defects were used as control. Histology observation showed the MSCs/PLGA-GCH repair group had better chondrocyte morphology, integration, continuous subchondral bone, and much thicker newly formed cartilage compared with MSCs/PLGA repair group 12 and 24 weeks postoperatively. There was a significant difference in histological grading score between these two groups, which both showed much better repair than control. The present study implied that the hybrid PLGA-GCH scaffold might serve as a new way to keep the differentiation of MSCs for enhancing cartilage repair.     

The effect of growth factor treatment on meniscal chondrocyte proliferation and differentiation on polyglycolic acid scaffolds

The aim of this investigation was to determine the effect of growth factor treatment on ovine meniscal chondrocyte (OMC) proliferation in vitro and on the production of matrix proteins by OMCs grown within a polyglycolic acid (PGA) scaffold. Analysis of 72-h monolayer cultures using the mean transit time (MTT) assay revealed a greater increase in OMC numbers in the presence of platelet-derived growth factor (PDGF)-AB, PDGF-BB, insulin-like growth factor (IGF)-I, transforming growth factor-beta1 (TGF-beta1) and basic fibroblast growth factor (bFGF) than in untreated controls. In contrast, IGF-II and bone morphogenetic protein-2 had no effect on OMC proliferation at the concentrations tested. The growth factors that elicited the greatest proliferative response (PDGF-AB, PDGF-BB, TGF-beta1, and IGF-I) were subsequently tested for their ability to enhance OMC proliferation and differentiation within PGA scaffolds. Biochemical analysis revealed less glycosaminoglycan (GAG) production in the presence of all growth factors tested compared to untreated control samples. In contrast, all of the growth factors increased collagen type I production by OMCs within the scaffolds at day 20, and all except PDGF-BB resulted in an increase at day 39, when compared to appropriate control samples. With the exception of IGF-I, none of the growth factors tested had any significant effect on collagen type II production. Histological staining of sections from OMC-PGA scaffolds did not reveal any difference in GAG or collagen production between the treatment groups. However, immunohistochemical analysis demonstrated an increase in collagen type I expression and a decrease in collagen type II at day 39 in all growth factortreated constructs, concomitant with a high infiltration of cells. This suggests that PDGF-AB, PDGF-BB, TGF-beta1, and IGF-1 may be useful in future tissue engineering studies for promoting meniscal cell proliferation and differentiation within scaffolds.     

氨基葡萄糖对白细胞介素1β诱导体外培养人骨关节炎软骨细胞蛋白聚糖代谢的影响

背景：蛋白聚糖和胶原纤维的降解是骨关节炎发病的主要生理和病理学基础,氨基葡萄糖不仅可以减轻骨关节炎疼痛症状,同时可以延缓骨关节炎的病理改变。 目的：了解氨基葡萄糖对白细胞介素1β诱导骨关节炎软骨细胞蛋白聚糖代谢的影响。 方法：取骨关节炎患者的软骨细胞,分阶段酶消化法进行体外原代培养。在培养液中加入白细胞介素1β诱导剂,设立不含药兔血清对照组、白细胞介素1β对照组和加入不同浓度兔氨基葡萄糖含药血清的实验组。 结果与结论：各浓度氨基葡萄糖含药血清组体外培养软骨细胞释放入培养液中糖胺聚糖百分比均值明显低于对照组(P < 0.01),随氨基葡萄糖浓度的增加,糖胺聚糖百分比逐渐降低;蛋白聚糖合成标记物3B3含量的均值较对照组明显增高(P < 0.01),与氨基葡萄糖浓度呈正相关;而蛋白聚糖降解标记物5D4含量的均值则正相反;氨基葡萄糖可以增加骨关节炎患者软骨细胞蛋白聚糖mRNA表达,减低基质金属蛋白酶1,3 mRNA表达。表明氨基葡萄糖可以抑制白细胞介素1β对骨关节炎患者软骨细胞蛋白聚糖代谢的促进作用,达到保护软骨,防止骨关节炎的目的。     

Combined effects of TGFbeta1 and BMP2 in serum-free chondrogenic differentiation of mesenchymal stem cells induced hyaline-like cartilage formation

This study investigated the effects of TGFbeta1, BMP2 or a combination of both on the chondrogenic differentiation of mesenchymal stem cells (MSCs) in a serum-free micromass culture system in vitro. Putative MSCs harvested from the iliac crest of 4-5 month old New Zealand White Rabbits were expanded and cultured in three-dimensional high density micromass aggregate cultures containing TGFbeta1, BMP2 or a combination of both, in the absence of serum. After 14-20 days of culture, chondrogenic differentiation of the MSCs was assayed by toluidine blue staining, immunohistochemistry and semi-quantitative RT-RCR of type I collagen (CI) and type II collagen (CII). Quantitative measurements of cell proliferation and sulfated glycosaminoglycan (s-GAG) were also carried out to assess the growth rate and matrix deposition of the cultured aggregates. Both immunohistochemical staining and semi-quantitative RT-PCR showed that the combination of BMP2 and TGFbeta1 resulted in a marked enhancement of collagen II synthesis, with minimal collagen I expression, which would suggest hyaline-like cartilage formation. Additionally, BMP2 and TGFbeta1 had a synergistic effect on matrix proteoglycan deposition, as assessed by metachromatic toluidine blue staining. This is consistent with the quantitative measurement of glycosaminoglycans, whereby a significant increase in GAG/DNA was noted in the co-treatment group. Hence, it can be concluded that the combination of BMP2 and TGFbeta1 has a synergistic effect on the differentiation of MSC into hyaline-like cartilage tissue.     

Trophic effects of mesenchymal stem cells in chondrocyte co-cultures are independent of culture conditions and cell sources

Earlier, we have shown that the increased cartilage production in pellet co-cultures of chondrocytes and bone marrow-derived mesenchymal stem cells (BM-MSCs) is due to a trophic role of the MSC in stimulating chondrocyte proliferation and matrix production rather than MSCs actively undergoing chondrogenic differentiation. These studies were performed in a culture medium that was not compatible with the chondrogenic differentiation of MSCs. In this study, we tested whether the trophic role of the MSCs is dependent on culturing co-culture pellets in a medium that is compatible with the chondrogenic differentiation of MSCs. In addition, we investigated whether the trophic role of the MSCs is dependent on their origins or is a more general characteristic of MSCs. Human BM-MSCs and bovine primary chondrocytes were co-cultured in a medium that was compatible with the chondrogenic differentiation of MSCs. Enhanced matrix production was confirmed by glycosaminoglycans (GAG) quantification. A species-specific quantitative polymerase chain reaction demonstrated that the cartilage matrix was mainly of bovine origin, indicative of a lack of the chondrogenic differentiation of MSCs. In addition, pellet co-cultures were overgrown by bovine cells over time. To test the influence of origin on MSCs' trophic effects, the MSCs isolated from adipose tissue and the synovial membrane were co-cultured with human primary chondrocytes, and their activity was compared with BM-MSCs, which served as control. GAG quantification again confirmed increased cartilage matrix production, irrespective of the source of the MSCs. EdU staining combined with cell tracking revealed an increased proliferation of chondrocytes in each condition. Irrespective of the MSC source, a short tandem repeat analysis of genomic DNA showed a decrease in MSCs in the co-culture over time. Our results clearly demonstrate that in co-culture pellets, the MSCs stimulate cartilage formation due to a trophic effect on the chondrocytes rather than differentiating into chondrocytes, irrespective of culture condition or origin. This implies that the trophic effect of MSCs in co-cultures is a general phenomenon with potential implications for use in cartilage repair strategies.     

Functionalization of dynamic culture surfaces with a cartilage extracellular matrix extract enhances chondrocyte phenotype against dedifferentiation

Culture on silicone rubber surfaces has been shown to partially overcome the chondrocyte dedifferentiation characteristic of standard culture on rigid polystyrene. These methods typically involve functionalization of culture surfaces with proteins. Collagen type I is often used, but more cartilage-specific proteins may be more appropriate for chondrocytes. To explore this hypothesis, a twofold experimental design was applied. First, chondrocytes were cultured in rigid Petri dishes coated with silicone rubber ("static silicone" or SS culture) functionalized with either cartilage extracellular matrix (ECM) extract or collagen type I. Second, chondrocytes were cultured on monotonically expanded high extension silicone rubber dishes ("continuous expansion" or CE culture) functionalized with ECM extract and compared to cells grown in SS culture. There were no differential effects of surface functionalization with the ECM extract vs. collagen type I on chondrocyte morphology, viability, proliferation or apoptosis in SS culture. However, chondrocyte growth on the ECM extract was associated with significantly reduced collagen types I and X gene expression and significantly increased glycosaminoglycan (GAG) secretion. After 3 passages (P3) on ECM-coated SS culture, chondrocyte phenotype and GAG secretion was enhanced compared to cells passaged on collagen type I. Pellet cultures from P3 SS culture displayed enhanced collagen type II content when ECM extract was used for functionalization rather than collagen type I. In CE culture with ECM functionalization, chondrocyte dedifferentiation was significantly inhibited vs. SS cultures, as evidenced by both gene expression and pellet cultures. Functionalization of extendable culture surfaces with cartilage ECM extract therefore supports enhanced preservation of chondrocyte phenotype.     

Ascorbate modulation of bovine chondrocyte growth,matrix protein gene expression and synthesis in three-dimensional collagen sponges

This report completes a previous study on the growth and metabolism of fetal bovine epiphyseal chondrocytes cultured, within native or cross-linked collagen sponges carried out without the addition of fresh ascorbate. At low initial cell density (2.3 x 10(6)cells/cm(3)) cell proliferation and a low matrix deposition were observed, whereas at high initial cell density (2.3 x 10(7)cells/cm(3)) there was an absence of cell proliferation, but the deposition of a cartilage-like matrix was measured. In both cases, only traces of type I collagen (marker of chondrocyte dedifferentiation) were detected. In this report, we observed, after 1 month in culture with ascorbate, in both type of scaffolds and initial cell densities, an increase in cell proliferation (2-fold) and in expression of genes encoding for collagen types I, II, X and MMP-2 and -13, but no change in the level of matrix deposition (collagen and GAG). With regard to the proteins present, the main differences with or without ascorbate concerned the increase of neosynthesised type I collagen (up to 35% of the total collagen deposited in the sponge) and of the MMP-2 active form. In conclusion, these results show that ascorbate is an important factor to consider when preparing cartilage constructs for its action on chondrocyte phenotype modulation and proliferation.     

染料木黄酮抑制生长板软骨细胞的增殖与基质合成

目的： 探讨染料木黄酮对大鼠肋生长板软骨细胞（RGC）的形态、增殖和胞外基质成分合成的影响。方法： 原代培养RGC，1×10^－6 μmol/L-1×10^－4 μmol/L染料木黄酮处理第1代RGC 24 h，观察RGC形态，同位素掺入检测RGC增殖、胶原和蛋白多糖合成，RT-PCR检测collagen Ⅱ和aggrecan基因表达。结果： 染料木黄酮改变了RGC的形态，随着浓度的升高，突起和漂浮细胞的数量增加。染料木黄酮剂量依赖性地抑制RGC的增殖、胶原和蛋白多糖的合成（P<0.05），以及collagenⅡ和aggrecan mRNA的转录。结论： 染料木黄酮抑制RGC的增殖和胞外基质的合成。