To withstand physiological loading during lifetime, human synovial joints are covered and protected by a layer of low-friction, load-bearing tissue called articular cartilage. The unique mechanical function of articular cartilage largely depends on the composition and structural integrity of cartilage matrix. The matrix is produced by the highly specialized resident cells called chondrocytes. Under physiological loading, chondrocytes maintain the balance between degrading and synthesizing matrix macromolecules. By contrast, under excessive loading or injury, the degradation exceeds the synthesis causing joint degeneration and eventually osteoarthritis. Hence, the mechanoresponses of chondrocytes play an important role in the development of osteoarthritis. Despite its clear importance, the mechanobiology of articular chondrocytes is yet not well understood. To summarize our current understanding, here we review the studies on effect of mechanical forces on both mechanical and biological properties of articular chondrocytes. First, we present viscoelastic properties of structures like cell nucleus, chondrocyte, pericellular matrix, and chondron. Then, we present how these properties change in osteoarthritis. Finally, we discuss the responses of both normal and osteoarthritic chondrocytes to variety of mechanical stimuli. Studies reviewed here may provide novel insights in pathogenesis of osteoarthritis, and may help in developing effective biophysical treatment.
- articular cartilage
- joint loading
- Copyright © 2013, American Journal of Physiology - Cell Physiology