关节软骨细胞体外培养不同时间去分化现象发生过程及规律

目的 研究软骨细胞体外培养不同时间去分化现象发生过程及规律。方法 倒置显微镜观察体外培养软骨细胞形态变化；根据每代每日细胞计数结果，绘制生长曲线，检测细胞增殖能力；采用免疫组织化学方法检测软骨细胞分泌Ⅱ型胶原的变化规律。结果 随着培养时间的延长，软骨细胞形态发生明显的改变；细胞增殖能力及分泌细胞外基因Ⅱ型胶原的能力逐渐减低。结论 兔关节软骨细胞体外培养时第3代开始出现去分化现象，至第5代（8周）时去分化现象明显。     

海藻酸钠载体中成年兔关节软骨细胞生长情况

目的:软骨细胞单层培养条件下增殖较快,但极易失分化,在生物载体材料构成的立体环境中培养,则能较好的维持表型。实验以海藻酸钠为载体,观察兔关节软骨细表型及增殖情况。方法:实验于2005-09/2006-12在山西医科大学第二医院骨科实验室完成。①实验动物和材料:6月龄新西兰大白兔24只,雌雄各半。实验过程中对动物处置符合动物伦理学要求。海藻酸钠由青岛明月海藻公司提供。②实验方法:以培养液配制的0.4% Pronease酶、0.025%Ⅱ型胶原酶顺序消化兔软骨分离细胞,以4×109 L-1海藻酸钠的浓度制成细胞悬液。③实验评估:倒置显微镜观察细胞在海藻酸钠中的形态及增殖情况,检测细胞收获效率和存活率。苏木精-伊红染色和AB-PAS染色观察软骨细胞的生长情况及评价软骨分泌胶原的情况。免疫组织化学定性观察Ⅱ型胶原的含量变化及有无Ⅰ型胶原的产生。Alcian blue染色法测定细胞盘中蛋白多糖的含量变化。结果:①软骨经两步酶消化软骨基质逐步解离和降解,细胞被完全分离,消化分离的软骨细胞总数达到5×106,细胞成活率达95.5%。②软骨细胞与海藻酸钠复合后体外培养,细胞生长旺盛、增殖活跃,增殖成株状或岛状,株状细胞团周围有类似的软骨陷窝形成,细胞排列密集,核圆形。③Ⅱ型胶原免疫组化和AB-PAS染色均呈阳性,细胞盘中蛋白多糖含量随培养时间延长逐渐增加。结论:海藻酸钠凝胶能与软骨细胞完全嵌合,是一种良好的软骨组织工程材料。     

改良分步消化法培养原代软骨细胞

背景：胰蛋白酶和细菌胶原酶结合使用消化关节软骨基质获得大量纯度高的软骨细胞的方法步骤繁琐、过程复杂,容易污染,但更好的简单易行、安全可靠的方法至今少有报道。目的：采用改良分步消化法进行软骨细胞培养,以获取大量纯净的软骨细胞。方法：将新西兰白兔6只随机分2组,酶消化法组运用酶消化法分两步获取原代软骨细胞,对照组用传统法进行原代软骨细胞培养。培养1周后观察两组培养的软骨细胞的生长状态,并进行细胞鉴定、计数,评估改良后的方法对细胞的影响。结果与结论：酶消化法组采用0.2%Ⅱ型胶原酶消化软骨细胞,与对照组相比,可将6h以上的消化时间缩短至3h。两组原代软骨细胞培养24h均多呈圆形,悬浮状态,48h后贴壁,培养1周后,两组软骨细胞可铺满培养瓶底。结果证实,采用改良分步消化法进行软骨细胞培养,在缩短了消化时间的同时其细胞生长及形态变化均无改变,可以顺利获取大量纯净的软骨细胞。     

改良分步消化法培养原代软骨细胞

背景:胰蛋白酶和细菌胶原酶结合使用消化关节软骨基质获得大量纯度高的软骨细胞的方法步骤繁琐、过程复杂,容易污染,但更好的简单易行、安全可靠的方法至今少有报道.目的:采用改良分步消化法进行软骨细胞培养,以获取大量纯净的软骨细胞.方法:将新西兰白兔6只随机分2组,酶消化法组运用酶消化法分两步获取原代软骨细胞,对照组用传统法进行原代软骨细胞培养.培养1周后观察两组培养的软骨细胞的生长状态,并进行细胞鉴定、计数,评估改良后的方法对细胞的影响.结果与结论:酶消化法组采用0.2%Ⅱ型胶原酶消化软骨细胞,与对照组相比,可将6 h以上的消化时间缩短至3 h.两组原代软骨细胞培养24 h均多呈圆形,悬浮状态,48 h后贴壁,培养1周后,两组软骨细胞可铺满培养瓶底.结果证实,采用改良分步消化法进行软骨细胞培养,在缩短了消化时间的同时其细胞生长及形态变化均无改变,可以顺利获取大量纯净的软骨细胞.     

关节软骨细胞复合胶原海绵异位构建组织工程化软骨组织的可能性

目的：观察兔关节软骨细胞与胶原海绵在体外复合培养以及体内植入后异位成软骨情况。方法：采用酶消化法分离、培养幼兔关节软骨细胞，取第三代细胞以3&;#215;10^7/ml密度均匀接种于胶原海绵中，分别通过倒置显向镜和扫描电镜观察软骨细胞在载体材料上生长增殖情况；将体外培养10d的软骨细胞／胶原海绵复合物植入裸鼠背部皮下，术后12周取材，进行大体观察和HE染色。结果：软骨细胞均匀分布于胶原海绵的孔壁和网眼内，并可分泌基质样物；复合培养物体内植入12周后可以形成新生透明软骨组织。结论：胶原海绵可以作为软骨细胞生长的支架载体，异位构建出组织工程化软骨组织。     

自体血清与胎牛血清培养兔关节软骨细胞的生物学特性

背景：目前培养软骨细胞多使用胎牛血清。但近年异种血清培养组织向临床应用的安全性受到质疑,因此自体血清培养越来越受到重视。目的：比较体积分数10%兔自体血清与体积分数10%胎牛血清培养兔关节软骨细胞生物学特性的差异。方法：兔自体血清培养液制备后,分离培养兔关节软骨细胞,分别在体积分数10%自体血清和体积分数10%胎牛血清中进行单层传代培养至1,3,5代,采用光镜观察细胞形态变化,绘制生长曲线评估细胞增殖速度,观察甲苯胺蓝染色、Ⅰ,Ⅱ型胶原免疫组织化学染色结果,以流式细胞仪分析细胞Ⅰ,Ⅱ型胶原以及CD26,CD44的表达变化。结果与结论：①在细胞形态上自体血清和胎牛血清培养的软骨细胞差异不大。②自体血清培养的软骨细胞较胎牛血清培养的软骨细胞生长速度更快。③甲苯胺蓝染色结果示,无论是自体血清还是胎牛血清所培养的细胞,染色随代龄的增加逐渐变浅,细胞传至第5代时两组几乎均无异染。对于1代和3代细胞而言,自体血清培养的软骨细胞较胎牛血清所培养的软骨细胞较为深染。④Ⅰ型胶原的表达随代数的增加而增加,而Ⅱ型胶原的表达则随代数的增加而减少。在3代时自体血清培养的软骨细胞Ⅰ型胶原的表达水平低于胎牛血清培养的软骨细胞（P〈0.05）;在1代和3代时自体血清培养的软骨细胞Ⅱ型胶原的表达水平高于胎牛血清培养的软骨细胞（P〈0.05）。⑤CD26表达呈现先升高后降低的趋势,而CD44的表达不随传代数的增加而改变。提示同异体体积分数10%的胎牛血清相比,体积分数10%的自体血清培养的兔软骨细胞生长速度快,且在大部分指标上可以较好地保持细胞表型。     

应用组织工程学技术修复关节软骨缺损

目的：关节软骨缺损一直是临床上的一个难题。目前的治疗包括自体或异体骨软骨移植修复、软骨膜或骨膜移植修复、组织工程学技术的发展使体外培养软骨细胞修复关节软骨缺损进入了一个新的发展时期，通过查阅文献对体外培养软骨细胞修复关节软骨缺损进行综述。资料来源：应用汁算机检索Medline 1993-01／2004-06关于组织工程学技术修复关节软骨缺损的文章，检索词为“articular cartilage defects、tissue engineering technology”，限定语言种类为英文；同时计算机检索中国期刊数据库1993-01／2004-06相关组织工程学技术修复关节软骨缺损的文章，检索词“关节软骨缺损，组织工程学技术，体外培养”，限定语言种类为中文资料选择：对资料进行初审，纳入标准：小有关软骨细胞的结构、功能、及其体外培养的意义研究：②有关体外培养种子细胞的选择的研究：⑧软骨细胞修复关常软骨缺损的前景展望的研究。排除标准：文献中重复研究、综述、Mata分析类文章：未排除文章中资料是否应用了随机、对照和盲法。资料提炼：共收集到32篇相关文献，含追溯法查找文献6篇，18篇符合纳入标准，排除14篇文献，其中4篇系重复研究，7篇为临床应用，3篇为软骨细胞支架的研究。18篇文献中有7篇对软骨细胞的特征进行综述，5篇是理想种子细胞的选择的研究，6篇为软骨细胞修复关节软骨缺损的前景展望的研究一资料综合：软骨细胞体外培养大量扩增、分化维持其正常的表型及代谢的调控因素为组织工程化软骨修复软骨缺损、体外培养软骨细胞建立软骨细胞库开拓了一条新的途径：软骨细胞，间充质干细胞（骨髓、骨膜或软骨膜来源）、滑膜细胞或转基因细胞等均町作为种子细胞。可来源于同种异体甚至异种细胞。自体软骨细胞植入技术已经作为一个传统自体软骨细胞移植术的替代品被骨科界广泛接受：结论：体外培养软骨细胞技术，目前已经成熟。组织工程学技术修复关节软骨缺损的方法很多：组织工程学技术的发展使体外培养转骨细胞修复关节软骨缺损进入了一个新的发展时期，基质诱导的自体软骨细胞植入技术修复关节软骨缺损开辟了新的道路。     

人鼻中隔软骨细胞体个和生物学特性组织修复

目的探讨人鼻中隔软骨细胞在体外培养条件下的生物学特性,为组织工程化软骨提供合适的种子细胞.方法取手术切除之鼻中隔软骨,经0.3%Ⅱ型胶原酶液消化分离获得软骨细胞,F12培养基培养,作形态学和Ⅱ型胶原免疫组化观察、细胞贴壁率和生长曲线测定.结果传9代细胞的增殖能力明显降低,传6代以后已无Ⅱ型胶原的表达.结论人鼻中隔软骨细胞作组织工程的种子细胞应以6代内为宜.     

体外传代培养兔关节软骨细胞的去分化现象

背景：兔是软骨组织工程研究中应用非常广泛的实验动物模型,关节软骨细胞的去分化现象已经被广泛认可.目的：观察体外传代培养过程中兔关节软骨细胞的去分化现象.方法：将从新西兰大白兔膝关节分离获取的原代软骨细胞进行传代培养至第7代,对细胞生长、形态、基质分泌以及基因表达等方面分别采用细胞计数,显微镜观察,F机动蛋白染色、番红O染色,糖胺聚糖定量测定以及半定量聚合链式反应进行鉴定和比较.结果与结论：光学显微镜下,兔关节软骨细胞在体外传代培养过程中细胞形态由小且圆形或多角形,逐步转变大且为成纤维细胞样的梭形形态,对F机动蛋白的染色进一步佐证了这样的形态变化.细胞计数结果表明,细胞增殖能力随代次增加显著下降,特别是第3代以后的软骨细胞基本无明显增殖;经过番红 O 染色以及定量测定糖胺聚糖的含量,发现软骨特性胞外基质分泌量从第2代细胞开始就呈现显著的降低.半定量聚合链式反应检测结果表明,随着传代次数的增加,特别是第3代以后,软骨相关特征分子（包括Ⅱ型胶原、聚集蛋白聚糖、软骨寡聚基质蛋白和SOX9等）基因表达水平下调;而与去分化相关的特征分子Ⅰ型胶原和多能蛋白聚糖基因表达水平上调,同时,细胞表面分子CD90基因表达上调,而CD14基因表达未见明显变化.结果证实,兔软骨细胞在体外传代过程中可出现快速地去分化现象,呈现出特征基因表达水平的变化,第3代以内的软骨细胞适合应用于软骨组织再生修复.     

骺板软骨细胞的体外培养及鉴定

目的:建立体外培养及鉴定骺板软骨细胞的方法。方法:实验于2005-03/2006-05在苏州大学附属儿童医院骨科实验室完成。选用3只生后14～28d的新西兰幼兔,空气栓塞处死,暴露股骨下端和胫骨上端,分别取2处的骺板组织,将其剪切成1～3mm3的小块,经胰蛋白酶消化,接种于含150g/L牛血清的1640培养基中,饱和湿度培养,传代。①细胞接种后3h在倒置显微镜下观察细胞生长情况,见细胞贴壁后每天观察2次。②第2代细胞达到80%～90%左右汇合时采用常规苏木精-伊红染色,光镜观察细胞爬片情况。③第3代细胞爬片至细胞达到80～90%左右汇合时,采用苏木素染色3min,3%亮绿染色5min,蕃红花“O”染色5min,光镜观察细胞产生蛋白聚糖情况。④采用PCR检测细胞Ⅱ型胶原的表达。⑤采用四唑盐MTT比色法检测细胞活性。结果:①骺软骨细胞刚接种后呈大小不等之圆形悬浮于培养液中,3h后见大部分细胞贴壁,24h后贴壁细胞呈短梭形、圆形、三角形和不规则形,见细胞分裂相。48h后见细胞伸展明显,细胞分裂相每高倍镜视野可见多个。经隔日换液细胞生长至第5天,细胞呈聚集生长,达到汇合状态,将细胞传代。接种后第1代细胞2d后呈梭形,培养4d传至第2代,第2代细胞长满瓶底后,90%呈胞膜较厚的圆形,10%为梭形,第3代、第4代亦如此。传至第5代见肥大细胞增多,细胞松散,折光性减弱,呈凋亡状态。②细胞爬片后观察骺软骨细胞形态以梭形居多,同时也有圆形、三角形和不规则形。可见细胞分裂及细胞中的分泌小泡。③见细胞呈红色,无绿色,证明蕃红花“O”-亮绿染色阳性,显示所培养的细胞可以分泌蛋白聚糖。④PCR检测术所养细胞含有Ⅱ型胶原,电泳带在440bp上。⑤四唑盐MTT比色法检测显示,第3代骺软骨细胞的生长曲线近似倒“S”形,在第4,5,6天细胞呈对数生长,约在7,8,9,10d达平台期,至第12天细胞出现生长抑制。结论:建立了骺板软骨细胞的体外培养方法,并证实所培养出的细胞分泌蛋白聚糖和Ⅱ型胶原,具有软骨细胞的共同特点。     

Propagation of surface fissures in articular cartilage in response to cyclic loading in vitro

Background. Mechanical overloading of synovial joints can damage the articular cartilage surface and may lead to osteoarthritis. However, causal links between mechanical and biological events in cartilage are poorly understood.

Objectives. To test the hypothesis that surface fissures in cartilage can propagate mechanically if the joint surface is subjected to vigorous cyclic loading.

Methods. Thirty-five cartilage-on-bone specimens, 15-mm square, were removed from mature bovine knee and shoulder joints. Specimens were loaded by means of a 9-mm-diameter flat indenter with a beveled edge, and their compressive strength determined. Failure occurred in the cartilage surface at an average stress of 36 MPa. Cartilage fissures were marked with Indian ink, photographed, and their length and width measured using image analysis software. Each damaged specimen was subjected to cyclic loading at 40% of its compressive strength, at 0.5 Hz, for up to 5 h. Fissure length and width were measured at regular intervals. After testing, fissure depth was measured from histological sections, and compared with measurements from damaged cartilage which was not cyclically loaded.

Results. Cyclic loading caused cartilage fissures to increase in length (mean 353%, P<0.01) and width (360%, P<0.01) but not depth. Propagation was rapid at first, but approached equilibrium after several hundred cycles. Rehydration in saline had no effect on fissure length, but width returned to pre-cyclic loading values.

Conclusion. Cartilage fissures can propagate mechanically when a joint surface is subjected to cyclic compressive loading in vitro. The transient opening-up of fissures to form wide surface “wounds” during cyclic loading could be of biological significance if it occurred in living people.Relevance

In living joints, wide open fissures in the cartilage surface could promote degenerative changes in the tissue.     

Human articular chondrocytes on macroporous gelatin microcarriers form structurally stable constructs with blood‐derived biological glues in vitro

Biodegradable macroporous gelatin microcarriers fixed with blood‐derived biodegradable glue are proposed as a delivery system for human autologous chondrocytes. Cell‐seeded microcarriers were embedded in four biological glues—recalcified citrated whole blood, recalcified citrated plasma with or without platelets, and a commercially available fibrin glue—and cultured in an in vitro model under static conditions for 16 weeks. No differences could be verified between the commercial fibrin glue and the blood‐derived alternatives. Five further experiments were conducted with recalcified citrated platelet‐rich plasma alone as microcarrier sealant, using two different in vitro culture models and chondrocytes from three additional donors. The microcarriers supported chondrocyte adhesion and expansion as well as extracellular matrix (ECM) synthesis. Matrix formation occurred predominantly at sample surfaces under the static conditions. The presence of microcarriers proved essential for the glues to support the structural takeover of ECM proteins produced by the embedded chondrocytes, as exclusion of the microcarriers resulted in unstable structures that dissolved before matrix formation could occur. Immunohistochemical analysis revealed the presence of SOX‐9‐ and S‐100‐positive chondrocytes as well as the production of aggrecan and collagen type I, but not of the cartilage‐specific collagen type II. These results imply that blood‐derived glues are indeed potentially applicable for encapsulation of chondrocyte‐seeded microcarriers. However, the static in vitro models used in this study proved incapable of supporting cartilage formation throughout the engineered constructs. Copyright © 2009 John Wiley & Sons, Ltd.     

Chondrogenic differentiation of human chondrocytes cultured in the absence of ascorbic acid

Bioreactor systems will likely play a key role in establishing regulatory compliant and cost‐effective production systems for manufacturing engineered tissue grafts for clinical applications. However, the automation of bioreactor systems could become considerably more complex and costly due to the requirements for additional storage and liquid handling technologies if unstable supplements are added to the culture medium. Ascorbic acid (AA) is a bioactive supplement that is commonly presumed to be essential for the generation of engineered cartilage tissues. However, AA can be rapidly oxidized and degraded. In this work, we addressed whether human nasal chondrocytes can redifferentiate, undergo chondrogenesis, and generate a cartilaginous extracellular matrix when cultured in the absence of AA. We found that when chondrocytes were cultured in 3D micromass pellets either with or without AA, there were no significant differences in their chondrogenic capacity in terms of gene expression or the amount of glycosaminoglycans. Moreover, 3D pellets cultured without AA contained abundant collagen Types II and I extracellular matrix. Although the amounts of Collagens II and I were significantly lower (34% and 50% lower) than in pellets cultured with AA, collagen fibers had similar thicknesses and distributions for both groups, as shown by scanning electron microscopy imaging. Despite the reduced amounts of collagen, if engineered cartilage grafts can be generated with sufficient properties that meet defined quality criteria without the use of unstable supplements such as AA, bioreactor automation requirements can be greatly simplified, thereby facilitating the development of more compact, user‐friendly, and cost‐effective bioreactor‐based manufacturing systems.     

成人关节软骨细胞增殖与人参皂甙Rg1的促进作用

背景：人参总皂甙的主要有效成分为人参皂甙Rg1,有促进细胞增殖、抗衰老、抗细胞凋亡、抗炎及抗自由基等作用,但以往实验对象多为鼠、兔等动物的关节软骨细胞。目的：体外培养成人软骨细胞,观察人参皂甙Rg1对体外培养的成人关节软骨细胞增殖的促进作用。方法：实验分2组,Rg1组使用含质量浓度为40mg/L人参皂甙Rg1的DMEM培养液培养,对照组使用未加人参皂甙的DMEM培养液培养,每日应用倒置相差显微镜观察细胞生长情况至第7天,并进行细胞计数。同时培养至第6天检测软骨细胞中Ⅱ型胶原的表达。结果与结论：对照组自培养第2天起细胞进入对数增殖期,到第7天细胞数约为接种时的8倍。Rg1组自培养第2天起细胞增殖能力较对照组增强（P〈0.05）,到第7天细胞数约为接种时的18倍（P〈0.05）。免疫组织化学SABC法检测结果显示,Rg1组与对照组细胞胞浆均可见Ⅱ型胶原表达,两组差异无显著性意义（P〉0.05）。说明人参皂甙Rg1可促进成人软骨细胞的增殖。     

Performance of new gellan gum hydrogels combined with human articular chondrocytes for cartilage regeneration when subcutaneously implanted in nude mice

Gellan gum is a polysaccharide that has been recently proposed by our group for cartilage tissue‐engineering applications. It is commonly used in the food and pharmaceutical industry and has the ability to form stable gels without the use of harsh reagents. Gellan gum can function as a minimally invasive injectable system, gelling inside the body in situ under physiological conditions and efficiently adapting to the defect site. In this work, gellan gum hydrogels were combined with human articular chondrocytes (hACs) and were subcutaneously implanted in nude mice for 4 weeks. The implants were collected for histological (haematoxylin and eosin and Alcian blue staining), biochemical [dimethylmethylene blue (GAG) assay], molecular (real‐time PCR analyses for collagen types I, II and X, aggrecan) and immunological analyses (immunolocalization of collagen types I and II). The results showed a homogeneous cell distribution and the typical round‐shaped morphology of the chondrocytes within the matrix upon implantation. Proteoglycans synthesis was detected by Alcian blue staining and a statistically significant increase of proteoglycans content was measured with the GAG assay quantified from 1 to 4 weeks of implantation. Real‐time PCR analyses showed a statistically significant upregulation of collagen type II and aggrecan levels in the same periods. The immunological assays suggest deposition of collagen type II along with some collagen type I. The overall data shows that gellan gum hydrogels adequately support the growth and ECM deposition of human articular chondrocytes when implanted subcutaneously in nude mice. Copyright © 2009 John Wiley & Sons, Ltd.     

体外培养软骨细胞与生长因子的加入

背景:自体软骨细胞体外培养生长缓慢,极易发生去分化,胰岛素样生长因子和碱性成纤维细胞生成因子可以刺激关节软骨细胞的增殖和分化.目的:观察应用碱性成纤维细胞生成因子和胰岛素样生长因子1对关节软骨细胞的作用.方法:采用成人关节软骨细胞体外培养,以碱性成纤维细胞生成因子(10μg/L)和胰岛素样生长因子1(100 mg/L)对其作用,采用MTT法和免疫细胞化学技术进行观察和评价.结果与结论:在体外培养软骨细胞时应用碱性成纤维细胞生成因子可以明显促进细胞增殖,但同时发生去分化.在体外培养软骨细胞时应用胰岛素样生长因子1可以明显促进细胞产生细胞外基质,有利于软骨细胞表型的表达,对细胞的增殖作用不明显.提示采用顺序性应用胰岛素样生长因子1和碱性成纤维细胞生成因子对体外培养的软骨细胞进行作用,可以在更短的时间内获得大量的、具有良好细胞表型的软骨细胞.     

Effect of cell seeding concentration on the quality of tissue engineered constructs loaded with adult human articular chondrocytes

Many aspects of the process of in vitro differentiation of chondrocytes in three-dimensional (3D) scaffolds need to be further investigated. Chitosan scaffolds were produced by freeze-drying 3% w/v 90% DDA chitosan gels. The effect of the cell seeding concentration was evaluated by culturing human adult chondrocytes in chitosan scaffolds After the first passage, cells were seeded into chitosan scaffolds with a diameter of 8 mm. The final cell seeding concentration per cm3 of chitosan scaffold was: Group A, 3 x 10(6); Group B, 6 x 10(6); Group C, 12 x 10(6); and Group D, 25 x 10(6) cells. After 14 and 28 days in 3D culture, the constructs were assesed for collagen, glucosaminoglycans and DNA content. The mechanical properties of the constructs were determined using a dynamic oscillatory shear test. The histological aspect of the constructs was evaluated using the Bern score. The collagen and GAG concentration increased, varying the cell seeding concentration. There was a significant increase in proteoglycan and hydroxyproline production between groups C and D. The sulphated GAG content increased significantly in the group D as compared to the other groups. The mechanical properties of the different constructs increased over time, from 9.6 G'/kPa at 14 days of 3D culture to 14.6 G'/kPa at 28 days under the same culture conditions. In this study we were able to determine that concentrations of 12-25 million cells/cm2 are needed to increase the matrix production and mechanical properties of human adult chondrocytes under static conditions.     

Strain dependence of ultrasound speed in bovine articular cartilage under compression in vitro

The change of the ultrasound (US) speed in articular cartilage (artC) under applied strain conditions may induce significant measurement errors of the mechanical properties of the artC during both indentation and compression tests using US. In this paper, the strain dependence of the US speed in bovine artC (n = 20) under compression in vitro was investigated by virtue of using a custom-made US compression testing system. The US speed of the artC at the instant after the compression and that after a period of stress-relaxation were estimated under the applied strain ranging from 0% to 20%. Moreover, the instantaneous modulus and the modulus after the stress-relaxation of the artC were measured and correlated with the US speed. There was no significant difference (p > 0.05) between the US speed at the instant after the compression and that after the stress-relaxation, although there was a discrepancy between the instantaneous modulus and the modulus after stress-relaxation. The US speed was found to be highly correlated to the applied strain (r(2) = 0.98, p < 0.001) in a quadratic relation and changed by 7.8% (from 1581 +/- 36 m/s to 1671 +/- 56 m/s) when the applied strain reached 20%. The results suggest that the strain-dependent effect on the US speed in artC should be considered when the US is deployed for the assessment of artC using the compression or indentation test.