Pilgaard L, Lund P, Duroux M, Fink T, Ulrich-Vinther M, Søballe K, Zachar V
Laboratory for Stem Cell Research, Aalborg University, Fredrik Bajers Vej 3B, 9220 Aalborg, Denmark.
Regen Med. 2009 Jul;4(4):539-48. doi: 10.2217/rme.09.28.
The chondrogenic differentiation potential of the easily accessible adipose tissue-derived stem cells (ASCs) is of particular interest within the field of tissue engineering for treating cartilage defects. However, no consensus has been reached as to which oxygen tension is more beneficial for the differentiation process.
MATERIALS & METHODS: In this investigation, the impact of available oxygen was investigated to identify optimal conditions for human ASC chondrogenesis in vitro. Four physiologically relevant oxygen concentrations of 15, 10, 5 and 1% were compared with ambient air condition, and the ASCs originating from six unrelated donors were subjected to chondrogenic induction in high-density pellet cultures.
The qualitative and quantitative assessment of accumulated extracellular matrix and the gene-expression analysis revealed marked interindividual differences, nevertheless the chondrogenic process was optimally supported in high-density pellet setup at ambient or 15% oxygen concentrations, irrespective of the origin of cells. The histochemical analysis based on alcian blue staining demonstrated that the differentiation took place in a gradient-like fashion, displaying highest levels in restricted regions, most often adjacent to the periphery. The two lowest hypoxic conditions, at 5 and 1% oxygen, seemed to have an inhibitory effect.
The micropellet cultures at ambient or 15% oxygen concentration provided the most suitable environment for inducing chondrogenesis in ASCs. Furthermore, in light of the fact that the induction appeared in a zone-dependent manner, this format lends itself as a suitable model for further analysis of the relationship between chondrogenic differentiation and the gradient of nutrients.
在组织工程领域，易于获取的脂肪组织来源干细胞（ASC）的软骨形成分化潜能对于治疗软骨缺损尤为重要。然而，关于哪种氧张力对分化过程更有利尚未达成共识。
在本研究中，研究了可用氧的影响，以确定体外人ASC软骨形成的最佳条件。将15%、10%、5%和1%这四种生理相关氧浓度与环境空气条件进行比较，并对来自六个无关供体的ASC在高密度微团培养中进行软骨形成诱导。
对积累的细胞外基质进行定性和定量评估以及基因表达分析显示出明显的个体差异，尽管如此，无论细胞来源如何，在环境或15%氧浓度的高密度微团培养中软骨形成过程得到了最佳支持。基于阿尔辛蓝染色的组织化学分析表明，分化以梯度样方式发生，在受限区域（最常见于周边附近）显示出最高水平。两种最低的低氧条件，即5%和1%的氧浓度，似乎具有抑制作用。
环境或15%氧浓度的微团培养为诱导ASC软骨形成提供了最合适的环境。此外，鉴于诱导以区域依赖性方式出现，这种形式适合作为进一步分析软骨形成分化与营养物质梯度之间关系的模型。
