The volume and morphology of chondrocytes within non-degenerate and degenerate human articular cartilage

Objective: Cartilage swelling is an early event in osteoarthritis (OA). However, the response of chondrocytes to increased tissue hydration is unknown. This work studied the volume and morphology of living in situ human chondrocytes as a function of cartilage degeneration. Methods: The tibial plateaus from knee joints of 40 patients were obtained following above-knee amputations or knee arthroplasty, and degree of cartilage degeneration from 0 (non-eroded) to 3 (extensive fibrillations) was assessed using several criteria. In situ chondrocytes were labeled with fluorescent indicators (calcein for living cells, propidium iodide for dead cells) permitting the quantification of volume and visualisation of morphology of cells within the cartilage zones by confocal scanning laser microscopy (CLSM). Results: Chondrocyte volume within superficial and mid-zones, but not of deep zone cells, increased significantly ( P