Lee R B, Wilkins R J, Razaq S, Urban J P G
Physiology Laboratory, Oxford University, Oxford, UK.
Biorheology. 2002;39(1-2):133-43.
Cartilage is routinely subjected to varying mechanical stresses which are known to affect matrix turnover by a variety of pathways. Here we show that mechanical loads which suppress sulphate incorporation or protein synthesis by articular chondrocytes, also inhibit rates of oxygen uptake and of lactate production. Although the mechanisms have not been definitively identified, it has been shown that high hydrostatic pressures reduce the activity of the glucose transporter GLUT. Furthermore, fluid expression consequent on static loading changes intracellular pH and ionic strength; intracellular changes which would reduce the activity of glycolytic enzymes. Both pathways would thus lead to a fall in rates of glycolysis and a reduction in intracellular ATP, and - since ATP concentrations directly affect sulphation of proteoglycans - a rapid fall in sulphate incorporation. Our results suggest that load-induced changes in matrix synthesis in cartilage can occur by means other than changes in gene expression.
软骨通常会受到各种不同的机械应力，已知这些应力会通过多种途径影响基质更新。在此我们表明，抑制关节软骨细胞硫酸盐掺入或蛋白质合成的机械负荷，也会抑制氧气摄取率和乳酸生成率。尽管其机制尚未明确，但已表明高静水压力会降低葡萄糖转运蛋白GLUT的活性。此外，静态负荷导致的液体排出会改变细胞内pH值和离子强度；这些细胞内变化会降低糖酵解酶的活性。因此，这两种途径都会导致糖酵解速率下降和细胞内ATP减少，并且——由于ATP浓度直接影响蛋白聚糖的硫酸化——硫酸盐掺入迅速减少。我们的结果表明，软骨中负荷诱导的基质合成变化可以通过基因表达变化以外的其他方式发生。
