Oxygen consumption of equine articular chondrocytes: Influence of applied oxygen tension and glucose concentration during culture

Abstract

We investigated the oxygen (O 2 ) uptake of equine articular chondrocytes to assess their reactions to anoxia/reoxygenation. They were cultured under 5% or 21% gas phase O 2 and at glucose concentrations of 0, 1.0 or 4.5 g/L in the culture medium (n = 3). Afterwards, the O 2 consumption rate of the chondrocytes was monitored (oxymetry) before and after an anoxia period of 25 min. The glucose consumption and lactate release were measured at the end of the re-oxygenation period. The chondrocytes showed a minimal O 2 consumption rate, which was hardly changed by anoxia. Independently from the O 2 tension, glucose uptake by the cells was about 30% of the available culture medium glucose, thus higher for cells at 4.5 g/L glucose (n = 3). Lactate release was also independent from O 2 tension, but lower for cells at 4.5 g/L glucose (n = 3). Our observations indicated that O 2 consumption by equine chondrocytes was very low despite a functional mitochondrial respiratory chain, and nearly insensitive to anoxia/re-oxygenation. But the chondrocytes metabolism was modified by an excess of O 2 and glucose.

Oxygen and reactive oxygen species in articular cartilage: modulators of ionic homeostasis

“…Thus, the density of mitochondria is low, approximating to about 1-2% of the volume of the cells (compared to 15-20% in other tissues [9]). These mitochondria may also have an incomplete complement of respiratory chain proteins: Cytochrome oxidase has been reported to be expressed at low levels, or even to be absent [72], although this has recently been challenged [94]. O 2 consumption is therefore low, although it is not zero.…”

“…O 2 consumption is therefore low, although it is not zero. At around 7×10 −15 mol cell h −1 , rates are only 2-5% of those for other cells [16,43,85,94,101]. Prolonged tissue culture at atmospheric O 2 levels (20% in standard incubators), therefore, represents a very abnormal O 2 level that may alter normal metabolism and gene expression.…”

“…It has become apparent that this is not only inappropriate for a cell originating from a tissue of much lower tension, but it is also harmful. Thus, cells survive better at 5% O 2 than is the case at 20% O 2 [94]. Morphologically, at higher O 2 tensions, chondrocytes lose their rounded shape and assume the spindle-like shape characteristic of fibroblasts [6,7,25,68,111] Matrix synthesis is greater quantitatively and qualitatively at 5% O 2 than at 20% O 2 [19,111,113].…”

Clinical and pathogenetic interrelation between molecular regulation of apoptosis and cell differentiation in osteoarthritis

“…Активация факторов транскрипции служит, с одной стороны, защитой кле-ток-участников патогенеза ОА от окси-дативного стресса и провоспалительных цитокинов [5], с другой -поддерживает па-тологические фенотипы клеточной диффе-ренцировки и запускает апоптоз [6]. В ряде исследований было показано, что при ОА есть тенденция к усилению проапоптоти-ческих и антипролиферативных процес-сов в костной ткани.…”

A pendulum test as a tool to evaluate viscous friction parameters in the equine fetlock joint

“…Indeed, unsaturated SAPLs are present as bilayers in an antioxidant and hydrophilic environment, such as the joint (Trunfio Sfarghiu, 2006), where the tension of oxygen (O 2 ) is low (7%) (Grimshaw and Mason, 2000;Schneider et al, 2007). When SAPLs are present in ambient air (O 2 21%), the phospholipid bilayers are transformed into hydrophobic phospholipid mono-layers and the unsaturated connections are oxidised in oxirane (oxygen fixation) and then in diol (H 2 O fixation) (Trunfio Sfarghiu, 2006).…”