Osteoarthritis (OA) remains incurable in humans or horses and mesenchymal stromal/stem cells (MSCs) represent an attractive solution for producing a neocartilage substitute. However, the best MSC source still needs to be identified. This study compared the chondrogenic potential of equine MSCs derived from bone marrow (BM) and umbilical cord blood (UCB), at their undifferentiated status to check if one cell source is better proned, and after chondrogenic-induced differentiation. Chondrogenesis was induced by culture in collagen scaffold with BMP-2 + TGF-ß1 in hypoxia or normoxia. MSCs chondrogenic potential was evaluated using the mRNA and corresponding protein levels for osteogenic, hypertrophic and chondrogenic markers. MSCs characterization demonstrated that BM- and UCB-MSCs differ in proliferation and tripotencies. At undifferentiated status, they also showed differences in their expression of osteogenic, chondrogenic and hypertrophic markers. Upon chondrogenesis induction, both MSCs sources exhibited increased chondrogenic expression and produce an extracellular matrix (ECM) of better quality in hypoxia, although collagen I remained expressed. UCB-MSCs produced higher amounts of collagen II, particularly its IIB isoform, than BM-MSCs, but also collagen I and Htra1, regardless of the oxygen condition. Finally, immunohistochemistry revealed that the BM-MSCs synthesized an ECM of higher quality, regarding the more homogenous distribution of type IIB collagen, compared to UCB-MSCs. Considering collagen I as the major undesirable component in the neo-synthesis of in vitro cartilage, we recommend using BM-MSCs for horse cartilage engineering.

中文翻译：

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骨髓和脐带血用于软骨组织工程的间充质干细胞的软骨生成潜能的比较。

骨关节炎（OA）在人或马中仍然无法治愈，间充质基质/干细胞（MSC）代表了一种生产新软骨替代物的有吸引力的解决方案。但是，仍然需要确定最佳的MSC来源。这项研究比较了来自骨髓（BM）和脐带血（UCB）的马MSC在未分化状态下的软骨形成潜力，以检查一种细胞来源是否经过更好的分化，以及在软骨诱导的分化之后。在缺氧或常氧的情况下，在BMP-2 +TGF-ß1胶原蛋白支架中培养诱导软骨形成。使用mRNA和相应的蛋白水平评估成骨，肥大和成软骨标记的MSCs软骨形成潜力。MSCs的特征表明BM-和UCB-MSCs在增殖和三倍性方面有所不同。在未区分状态下，他们还显示出成骨，软骨形成和肥大性标志物的表达差异。诱导软骨形成后，两种MSC来源均显示出软骨生成增加的表达，并在缺氧时产生质量更好的细胞外基质（ECM），尽管胶原蛋白I仍然表达。UCB-MSC与BM-MSC相比，产生的胶原蛋白II（尤其是IIB异构体）数量更多，但无论氧气条件如何，胶原蛋白I和Htra1的数量均高于胶原蛋白。最后，免疫组化显示，与IIB型胶原相比，BM-MSC合成了质量更高的ECM，因为IIB型胶原的分布更均匀。考虑到胶原蛋白I是体外软骨新合成中的主要不良成分，我们建议将BM-MSC用于马软骨工程。