Effects of mechanical forces on the development and growth of cartilage

生物力学力被认为对骨骼组织的生长有重要影响。然而，尚不清楚生物力学力如何在这些组织中转化，或者它们在细胞活动中引起什么变化。生长板和关节软骨分别是重要的生长中心和缓冲垫。因此，我们研究了离心力对生长板和关节软骨细胞增殖及其细胞外基质合成的影响，结果表明，离心管中的生长板软骨细胞可以进行终末分化，然后引起细胞外基质的钙化，而关节软骨细胞几乎不显示任何终末分化，也不引起钙化。在兔关节软骨细胞中，脱水导致^3H-胸苷掺入DNA的增加，但对沉淀培养的生长板软骨细胞的DNA合成几乎没有影响。加 关于我们 关节和生长板软骨细胞的作用刺激蛋白多糖的合成。软骨细胞对机械力的反应中蛋白聚糖合成的增加可能是软骨组织强度增加所必需的，因为软骨对机械力的压缩刚度已被证明与糖胺聚糖浓度的增加有关。离心刺激软骨细胞合成蛋白多糖的机制尚不清楚。然而，在颗粒状兔软骨细胞培养物中，吲哚美辛不调节离心对β<35>-S-硫酸盐掺入蛋白聚糖的影响。因此，这是不可能的，三尖杉酯碱是通过离心力参与这些效果。由于软骨细胞产生胰岛素样生长因子（IGFs），转化生长因子β和软骨调节素，这些因子可能在介导机械力的作用中发挥作用。我们的研究结果提供了证据表明，机械力直接作用于软骨细胞，以调节其增殖和细胞外基质的合成。少

Biomechanical forces are thought to have significant effects on the growth of skeletal tissues. However, it is not known how biomechanical forces are translated in these tissues or what changes they cause in the cellular activities. Growth plate and articular cartilage are important as a growth center and a cushion, respectively. Therefore, we examined the effects of centrifugal force on the proliferation of growth-plate and articular chondrocytes and the syntheses of their extracellular matrix in pelleted cultures.We have shown that pelleted growth-plate chondrocytes in centrifuge tubes can undergo terminal differentiation and then cause calcification of the extracellular matrix, but articular cbondrocytes show scarcely any terminal differentiation asd do not cause calcification. Centrifugation resulted in increased ^3H-thymidine incorporation into DNA in rabbit articular chondrocytes, but had little effect on DNA synthesis in growth-plate chondrocytes in pelleted cultures. Centrifuga … More tion of articular and growth-plate chondrocytes stimulated proteoglycan synthesis. The increase in proteoglycan synthesis by chondrocytes in response to mechanical forces may be necessary for an increase in the strength of cartilaginous tissue, because compressive stiffness of cartilages to mechanical forces has beerv shown to be associated with an increase in the concentration of glycosaminoglycans. The mechanism by which centrifugation stimulates proteoglycan synthesis by chondrocytes is not known. However, in pelleted rabbit chondrocyte cultures, indomethacin did not modulate the effect of centrifugation on ^<35>S-sulf'ate incorporation into proteoglycans. Therefore, it is not likely that prostaglandins are involved in these effect by centrifugal force. Because chondrocytes produce insulinlike growth factors (IGFs), transforming growth factor-beta, and chondromodulins, these factors may play a role in mediating the effect of mechanical forces. Our results provide evidence that mechanical forces act directly on chondrocytes to modulate their proliferation and extracellular matrix synthesis. Less