Depth-dependent compressive behaviors of articular cartilage and chondrocytes

The natural synovial joints have excellent performance of long durability with low friction even under high load. To study metabolic mechanism in articular cartilage containing chondrocytes, it is important to know the actual structure and stress-strain state of the cartilage and extracellular matrix around chondrocytes during cartilage deformation, where chondrocytes seem to experience similar deformation to extracellular matrix. The articular cartilage of high water content has a biphasic viscoelastic property and shows the timedependent and depth-dependent deformation behavior. In this study, the morphology of chondrocyte was visualized, and the compressive behaviors in articular cartilage containing chondrocytes were observed in the compressive apparatus located in the stage of confocal laser scanning microscope. The time-dependent and depth-dependent behaviors of articular cartilage were evaluated by the finite element method for biphasic model.