Figure 5.

The thiol antioxidant N-acetyl-cysteine prevents ROS-induced DCDHF fluorescence, NF-κB translocation, and neuronal death induced by C₂-ceramide. N-acetyl-cysteine (20 mM) was added 1 hr before and during an 8-hr exposure to C₂-ceramide (25 μM), which was then withdrawn and the cells maintained in fresh N-acetyl-cysteine supplemented medium. The number of DCDHF fluorescent cells (see Fig. 4 legend) and the number of MAP-2-positive neurons with nuclear NF-κB staining were counted at their respective peaks, 5 and 8 hr after the initiation of C₂-ceramide treatment (see Fig. 4A) and neuronal survival at 36 hr. Data represent the mean number of neurons per well (×10³) ± SEM of three independent experiments. Significantly different from cultures treated with C₂-ceramide alone (∗, P < 0.05; ∗∗, P < 0.01, two-tailed t test).