Center for Joint Surgery, Southwest Hospital, Third Military Medical University, Chongqing, China;
Am J Physiol Cell Physiol. 2013 Dec 15;305(12):C1202-8. doi: 10.1152/ajpcell.00242.2013. Epub 2013 Sep 25.
To withstand physiological loading over a lifetime, human synovial joints are covered and protected by articular cartilage, a layer of low-friction, load-bearing tissue. The unique mechanical function of articular cartilage largely depends on the composition and structural integrity of the cartilage matrix. The matrix is produced by highly specialized resident cells called chondrocytes. Under physiological loading, chondrocytes maintain the balance between degradation and synthesis of matrix macromolecules. Under excessive loading or injury, however, degradation exceeds synthesis, causing joint degeneration and, eventually, osteoarthritis (OA). Hence, the mechanoresponses of chondrocytes play an important role in the development of OA. Despite its clear importance, the mechanobiology of articular chondrocytes is not well understood. To summarize our current understanding, here we review studies of the effect of mechanical forces on mechanical and biological properties of articular chondrocytes. First, we present the viscoelastic properties of the cell nucleus, chondrocyte, pericellular matrix, and chondron. Then we discuss how these properties change in OA. Finally, we discuss the responses of normal and osteoarthritic chondrocytes to a variety of mechanical stimuli. Studies reviewed here may provide novel insights into the pathogenesis of OA and may help in development of effective biophysical treatment.
为了在其一生中承受生理负荷，人类的滑膜关节被关节软骨覆盖和保护，这是一种低摩擦、承重的组织。关节软骨的独特机械功能在很大程度上取决于软骨基质的组成和结构完整性。基质是由高度特化的常驻细胞——软骨细胞产生的。在生理负荷下，软骨细胞维持着基质大分子降解和合成之间的平衡。然而，在过度负荷或损伤下，降解超过了合成，导致关节退化，最终发展为骨关节炎（OA）。因此，软骨细胞的力学反应在 OA 的发展中起着重要作用。尽管其重要性显而易见，但关节软骨细胞的力学生物学尚未被很好地理解。为了总结我们目前的认识，我们在这里回顾了机械力对关节软骨细胞力学和生物学特性的影响的研究。首先，我们介绍了细胞核、软骨细胞、细胞外基质和软骨小体的黏弹性特性。然后我们讨论了这些特性在 OA 中的变化。最后，我们讨论了正常和骨关节炎软骨细胞对各种机械刺激的反应。这里综述的研究可能为 OA 的发病机制提供新的见解，并有助于开发有效的生物物理治疗方法。
