Chondrocyte death and mitochondrial dysfunction are mediated by cartilage friction and shear strain

Mitochondrial dysfunction is an acute response of articular chondrocytes to mechanical injury

“…A better understanding of the mechanisms by which mechanical forces influence MT function may have important implications for development of disease‐modifying OA drugs and orthopedic regenerative therapies. For example, recent work suggests that chondrocyte MT depolarization is correlated with local shear strain during cartilage sliding, and connects MT depolarization and chondrocyte apoptosis with increased frictional coefficients due to inadequate cartilage lubrication …”

“…For example, recent work suggests that chondrocyte MT depolarization is correlated with local shear strain during cartilage sliding, and connects MT depolarization and chondrocyte apoptosis with increased frictional coefficients due to inadequate cartilage lubrication. 48 While the use of cartilage explants in this study provides a number of advantages for improving the physiological relevance, it also presents several limitations. The time required for diffusion of solutes through the dense extracellular matrix of cartilage is significantly greater compared to cells in 2D culture.…”

New algorithm for simulation of proteoglycan loss and collagen degeneration in the knee joint: Data from the osteoarthritis initiative

“…However, this kind of data is currently not available. Furthermore, a much lower shear strain (∼7–12%) was proposed recently for cell death, and presumably for subsequent PG loss, in another experimental study applied for cartilage . Therefore, different threshold levels for the initiation and progression of the PG depletion () were first tested (from 10% to 30%) and the results are shown for 15% and 17% strain thresholds, because they produced experimentally observed results.…”

“…It has been shown that cell death and PG depletion of cartilage may occur as a result of excessive levels of compressive and/or shear strains . On the other hand, deviatoric strain takes into account several strain components and was earlier implemented in a cartilage model to control the nonfibrillar matrix damage in indentation .…”

“…). We hypothesized that experimentally observed depth‐dependent PG depletion and collagen fibril degeneration can be simultaneously simulated at the joint level based on excessive tissue deviatoric strains and maximum principal stresses, adopted from earlier experimental in vitro studies . We also hypothesized that this result can only be obtained if the material model for cartilage includes depth‐dependent properties of the tissue.…”