Figure 4.

NACET strongly increases the intracellular GSH pool available to counteract oxidative stress. ARPE-19 RPE cells were treated for 16 h with 1 mM antioxidant (Antiox.) and 15 or 30 min before lysis were stressed with 2 mM H₂O₂ or 1 mM t-BOOH as oxidants (Ox.). GSH (a) and glutathione disulfide (GSSG) (b) concentrations were normalized to the concentration of total proteins (mean ± SD, number of replicates = 3). In panel (a), GSH concentrations are represented as blue bars for NAC-treated and untreated samples, and as red bars for NACET-treated samples. In panel (b), GSSG concentrations are represented as orange bars for NAC-treated and untreated samples, and as red bars for NACET-treated samples. ** p < 0.01; **** p < 0.0001; ns, not significant differences.