Smith R L, Donlon B S, Gupta M K, Mohtai M, Das P, Carter D R, Cooke J, Gibbons G, Hutchinson N, Schurman D J
Department of Functional Restoration, Veterans Affairs Medical Center, Palo Alto, California, USA.
J Orthop Res. 1995 Nov;13(6):824-31. doi: 10.1002/jor.1100130604.
This study tested the effects of fluid-induced shear on high density monolayer cultures of adult articular chondrocytes. Fluid-induced shear (1.6 Pa) was applied by cone viscometer to normal human and bovine articular chondrocytes for periods of 24, 48, and 72 hours. At 48 and 72 hours, fluid-induced shear caused individual chondrocytes to elongate and align tangential to the direction of cone rotation. Fluid-induced shear stimulated glycosaminoglycan synthesis by 2-fold (p < 0.05) and increased the length of newly synthesized chains in human and bovine chondrocytes. In human chondrocytes, the hydrodynamic size of newly synthesized proteoglycans also was increased. After 48 hours of fluid-induced shear, the release of prostaglandin E2 from the chondrocytes was increased 10 to 20-fold. In human chondrocytes, mRNA signal levels for tissue inhibitor of metalloproteinase increased 9-fold in response to shear compared with the controls. In contrast, mRNA signal levels for the neutral metalloproteinases, collagenase, stromelysin, and 72 kD gelatinase, did not show such major changes. This study demonstrated that articular chondrocyte metabolism responds directly to physical stimulation in vitro and suggests that mechanical loading may directly influence cartilage homeostasis in vivo.
本研究测试了流体诱导剪切力对成年关节软骨细胞高密度单层培养物的影响。通过锥板式粘度计对正常人和牛的关节软骨细胞施加流体诱导剪切力（1.6帕斯卡），持续24、48和72小时。在48和72小时时，流体诱导剪切力使单个软骨细胞伸长并沿锥旋转方向切线排列。流体诱导剪切力使糖胺聚糖合成增加了2倍（p<0.05），并增加了人和牛软骨细胞中新合成链的长度。在人软骨细胞中，新合成蛋白聚糖的流体力学尺寸也增加了。在流体诱导剪切力作用48小时后，软骨细胞中前列腺素E2的释放增加了10至20倍。在人软骨细胞中，与对照组相比，金属蛋白酶组织抑制剂的mRNA信号水平因剪切力而增加了9倍。相反，中性金属蛋白酶、胶原酶、基质溶解素和72kD明胶酶的mRNA信号水平没有显示出如此大的变化。本研究表明，关节软骨细胞代谢在体外直接对物理刺激作出反应，并提示机械负荷可能在体内直接影响软骨内环境稳定。
