Low Oxygen Reduces the Modulation to an Oxidative Phenotype in Monolayer-Expaned Chondrocytes
Low Oxygen Reduces the Modulation to an Oxidative Phenotype in Monolayer-Expaned Chondrocytes
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DOI：
10.1002/jcp.21946
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发表时间：
2010-01-01
影响因子：
5.6
通讯作者：
Lee, David A.
中科院分区：
文献类型：
--
作者：
Heywood, Hannah K.;Lee, David A.
自体软骨细胞植入需要一个体外细胞扩增阶段，通过在大气氧水平下单层培养来实现。软骨细胞在低氧条件下原位存在并表现出糖酵解代谢。然而，氧化磷酸化在培养过程中逐渐上升，伴随着活性氧的产生。我们确定是否在体外高氧环境提供了转化刺激。关节软骨细胞在2%、5%或20%氧气下单层培养长达14天。与20%氧气相比，2%和5%氧气下的扩增降低了细胞形成氧化表型的速率。然而，在40 +/- 4 fmol cell（-1）h（-1）时，在2%氧气下扩增14天的软骨细胞的耗氧量仍然是新鲜分离细胞所观察到的值的14倍。增加的耗氧量的75%至78%由氧化磷酸化（寡霉素敏感）引起。低氧条件下的扩张也减少了细胞增殖和8-羟基鸟苷的释放，这是氧化DNA损伤的标志。然而，与新鲜分离的细胞相比，这些参数仍然升高。因此，在生理氧水平下的膨胀减少但不消除氧化能量代谢的诱导。我们的结论是，简单地将软骨细胞转移到低氧环境不足以维持或重建正常的能量代谢。此外，促进圆形细胞形态的疏水聚苯乙烯培养表面对氧化代谢的发展没有影响。虽然向氧化能量代谢的转变往往伴随着形态学的变化，但这项研究并不支持它是由它们驱动的假设。J.细胞。222：248-253，2010。(C)2009 Wiley-Liss，Inc.
Autologous chondrocyte implantation requires a phase of in vitro cell expansion, achieved by monolayer culture under atmospheric oxygen levels. Chondrocytes reside under low oxygen conditions in situ and exhibit a glycolytic metabolism. However, oxidative phosphorylation rises progressively during culture, with concomitant reactive oxygen species production. We determine if the high oxygen environment in vitro provides the transformation stimulus. Articular chondrocytes were cultured in monolayer for up to 14 days under 2%, 5%, or 20% oxygen. Expansion under 2% and 5% oxygen reduced the rate at which the cells developed an oxidative phenotype compared to 20% oxygen. However, at 40 +/- 4 fmol cell(-1) h(-1) the oxygen consumption by chondrocytes expanded under 2% oxygen for 14 days was still 14 times the value observed for freshly isolated cells. Seventy-five to 78% of the increased oxygen consumption was accounted for by oxidative phosphorylation (oligomycin sensitive). Expansion under low oxygen also reduced cellular proliferation and 8-hydroxyguanosine release, a marker of oxidative DNA damage. However, these parameters remained elevated compared to freshly isolated cells. Thus, expansion under physiological oxygen levels reduces, but does not abolish, the induction of an oxidative energy metabolism. We conclude that simply transferring chondrocytes to low oxygen is not sufficient to either maintain or re-establish a normal energy metabolism. Furthermore, a hydrophobic polystyrene culture surface which promotes rounded cell morphology had no effect on the development of an oxidative metabolism. Although the shift towards an oxidative energy metabolism is often accompanied by morphological changes, this study does not support the hypothesis that it is driven by them. J. Cell. Physiol. 222: 248-253, 2010. (C) 2009 Wiley-Liss, Inc.