Mwale Fackson, Stachura Dorothy, Roughley Peter, Antoniou John
Lady Davis Institute for Medical Research and Department of Surgery, SMBD-Jewish General Hospital, McGill University, Montreal, Quebec, Canada.
J Orthop Res. 2006 Aug;24(8):1791-8. doi: 10.1002/jor.20200.
The study was initially designed to differentiate human bone marrow-derived mesenchymal stem cells (MSC) into chondrocyte-like cells, for use in tissue engineering. We cultured MSCs in defined chondrogenic medium as pellet cultures supplemented with transforming growth factor (TGF)-beta1 or -beta3 and dexamethazone, as they are commonly used to promote in vitro chondrogenesis. Markers of chondrogenesis used were type II collagen and aggrecan, with type X collagen being used as a marker of late-stage chondrocyte hypertrophy (associated with endochondral ossification). Our results show that aggrecan is constitutively expressed by MSCs and that type X collagen is expressed as an early event. Furthermore, we found that type X collagen was expressed before type II collagen in some cases. This is surprising because it is understood that stem cells have to be differentiated into chondrocytes before they can become hypertrophic. Thus, caution must be exercised when using aggrecan and type X collagen as markers for chondrogenesis and chondrocyte hypertrophy, respectively, in association with stem cell differentiation from this source.
该研究最初旨在将人骨髓间充质干细胞（MSC）分化为软骨样细胞，用于组织工程。我们将MSC在特定的软骨形成培养基中培养成小球培养物，并添加转化生长因子（TGF）-β1或-β3以及地塞米松，因为它们通常用于促进体外软骨形成。所使用的软骨形成标志物是II型胶原蛋白和聚集蛋白聚糖，X型胶原蛋白用作晚期软骨细胞肥大（与软骨内骨化相关）的标志物。我们的结果表明，聚集蛋白聚糖由MSC组成性表达，并且X型胶原蛋白在早期表达。此外，我们发现在某些情况下，X型胶原蛋白在II型胶原蛋白之前表达。这令人惊讶，因为据了解干细胞必须先分化为软骨细胞才能肥大。因此，在将聚集蛋白聚糖和X型胶原蛋白分别用作与源自该来源的干细胞分化相关的软骨形成和软骨细胞肥大的标志物时，必须谨慎行事。
