Figure 6. .

Autofluorescence bleaching and recovery in A2E-containing cells that were treated with sulforaphane and N-acetylcysteine to enhance GSH levels before irradiation. (A) Chromatographic display demonstrating detection by absorbance and mass. Inset, Top: UV-visible absorbance spectra; Bottom: mass to charge ratio (m/z). (B) Total fluorescence and absorbance were determined from total chromatographic peak area (430 nm monitoring) in non-irradiated (control) A2E-containing cells and A2E-containing cells analyzed 1, 8, and 24 hours after irradiation (6 minutes). Cells were allowed to accumulate sulforaphane and N-acetylcysteine 24 hours before irradiation (treated) or were not pretreated (untreated). Mean ± SEM, three experiments. (C) The m/z 626 species could reflect a diol forming by proton donation from GSH to endoperoxide-bearing A2E (m/z 624). (D) Proposed mechanism for conversion of endoperoxide to diol with proton donation from GSH. GSSG, oxidized glutathione.