The occurrence of chondrocyte apoptosis may be cri­tical in determining the extent of a lesion and sub­sequent repair after mechanical injury to articular cartilage. Agents that prevent apoptosis and increase chondrocyte survival may prove beneficial in the treatment of these ­lesions. This set of experiments was designed to determine the efficacy of some known apoptosis inhibitors in preventing chon­drocyte apoptosis after mechanical injury. In the first set of experiments, thirty full-thickness cartilage explants, 5 mm in diameter, were harvested from the weight-bearing regions of the medial femoral condyle of three fresh bovine joints with use of a dermal punch. Explants were cultured for forty-eight hours in Dulbecco modified Eagle medium supplemented with 10% fetal bovine serum. Explants were divided into three groups: control, loaded, and loaded + CI. The loaded group was subjected to a radially unconfined single static load of 23 MPa for 500 msec and recultured in fresh media for forty-eight hours postinjury. The loaded + CI group underwent the same loading, but the specimens were cultured in fresh media containing 100 mM of the caspase ­inhibitor z-VAD.fmk. The control group did not undergo loading. In a second set of experiments, forty-eight bovine cartilage explants were divided into four groups: control, loaded, loaded + D, and loaded + I. The loaded, loaded …