Cell viability. Total refers to all layers of cartilage explant (superficial, middle, deep). All agents were added to parallel cultures immediately after impaction on day 0 and were kept for 48 hours, after which they were replaced with fresh media only. Measurements were made on day 0 immediately following impaction, and then on days 2, 7, and 14. IC = impacted control; OP-1 = osteogenic protein-1 added at 100 ng/mL concentration; TNF = tumor necrosis factor-α (TNF-α) antagonist, 100 ng/mL; NAC = N-acetyl-l-cysteine, 2.5 mM; IL-RA = IL-1 receptor antagonist used at 20 ng/mL and 100 ng/mL; Pan-caspase inhibitor Z = Z-VAD-FMK pan caspase inhibitor, 100 µM; Pan-caspase inhibitor Q = Q-VD-OPh pan caspase inhibitor, 100 µM. Cell viability was assessed with Live/Dead Cell assay.