Ageing and excessive mechanical strain on the articular cartilage have both been associated with the development of knee osteoarthritis (OA). Cartilage degeneration in OA involves a senescent phenotype of chondrocytes, as well as modifications of the extracellular matrix (ECM). Research published in Bone Research investigates how mechanical signals in the form of altered ECM stiffness might lead to chondrocyte senescence in knee OA.

“While reviewing articles related to the mechanical response of chondrocytes in knee OA, we noticed that most studies focused on the effects of actively applied stresses on cartilage, such as shear, compression and tensile forces. However, as arthritis symptoms in patients with OA do not seem to be substantially relieved after bed rest, we hypothesized that mechanical signals in the resting state also have a crucial impact on cartilage,” notes Wenhua Huang, co-corresponding author of the study. Liu, Huang and colleagues thus set out to investigate how ECM stiffness is altered in a mouse model of knee OA induced by destabilization of the medial meniscus, as well as in cartilage samples from patients with OA, and how these changes affect chondrocyte phenotypes.