Fig. 5.

Inhibition of caspases 3, 8, and 9 blocks oxidant-induced cell death. Neuronal cultures exposed to 75 or 100 μm DTDP for 10 min in the presence of peptide and nonpeptide caspase inhibitors. The broad spectrum cysteine protease inhibitor BAF (10 μm), caspase 3, 7, and 9 selective nonpeptide inhibitor IS-4 (3 μm), and the caspase 8 selective inhibitor zLETD (10 μm) were present for 60 min before, during, and 24 hr after exposure to DTDP. Cell viability was assessed as above, and data are expressed as mean percentage neuroprotection compared with the same dose of DTDP without inhibitor ± SEM. Data represent the average of five experiments performed in duplicate. All compounds provided significant protection at both doses of DTDP tested. *p < 0.05; pairedt test.