[Cartilage/chondrocyte research and osteoarthritis. Mechanobiology for development of osteoarthritis.]

Articular cartilage is exquisitely sensitive to their mechanical environment, and mechanical loading may be the most important external factor regulating cartilage metabolism. Mechanical loading regulates chondrocyte activity, and pathological excessive loading leads to abnormal mechanotransduction, which in turn induces cartilage degradation. Several studies report that moderate levels of exercise exerts beneficial effects, such as improvements in pain and physical function, and also mitigates joint destruction through the down-regulation of the expression of matrix proteases. Calcium signaling is an initial step in chondrocyte mechanotransduction that has been linked to many cellular processes, and recent studies found that calcium ion channels distinctively mechanically activated by physiological or pathological mechanical loading through transient receptor potential vanilloid 4(TRPV4)or Piezo ion channels. We review here the recent progress on mechanotransduction of chondocytes, highlighting the calcium ion channels.