Figure 6.
TNF-α and C2-ceramide induce cell death in articular cartilage via a mechanism involving PKR. Bovine articular cartilage explants were cultured for 24 hours in the presence of (a)TNF-α (100 ng/ml) or (b) C2-ceramide (50 μM). 2-AP (1 or 10 mM) was added 1 hour before the addition of treatments. Viability of explant tissue was determined using the CytoTox 96® assay, which quantitatively measures lactate dehydrogenase released into culture media upon cell death during the culture period. Data shown are absorbance units per milligrams of starting tissue and are expressed as means ± SEM. *Significantly different from control explants at P < 0.05; **P < 0.01. 2-AP, 2-aminopurine; PKR, protein kinase R; TNF, tumour necrosis factor.