Proinflammatory cytokines such as TNF-?? have also been reported to stim-ulate cell death [16]; however, it is currently unclear if chondrocyte cell death is directly controlledby these cytokines.Studies of chondrocyte-mediated matrix turnover in a model for mechanical injury of car-tilage have shown that mechanical load can produce non-viable cell populations exhibiting con-densed nuclei [17], re