Glutathione modulates the level of free radicals produced in UVA-irradiated cells

J Photochem Photobiol B. 2000 Sep;57(2-3):102-12. doi: 10.1016/s1011-1344(00)00084-1.


We have developed an assay to detect reactive oxygen species (ROS) generated by UVA radiation utilising chemical probes which become fluorescent upon oxidation. Using a human bladder carcinoma cell line (MGH-U1) and spontaneously immortalised keratinocytes (HaCaT), we have shown a UVA (narrow band 365+/-5 nm) dose-dependent increase in fluorescence by flow cytometry following loading of the cells with either dihydrorhodamine 123 (DHR) or 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA). The UVA response of both DHR and DCFH was enhanced by elevation of intracellular levels of the photosensitiser protoporphyrin IX by incubation for 2.5 h with 5-aminolaevulinic acid. Depletion of the antioxidant glutathione (GSH) using the inhibitor D,L-buthionine-sulphoximine (BSO), resulted in an increase in the UVA-induced fluorescence of DCF but not of rhodamine 123. Conversely, raising intracellular GSH levels with N-acetyl cysteine (NAC) had relatively little protective effect in terms of degree of induced fluorescence.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylcysteine / metabolism
  • Acetylcysteine / pharmacology
  • Antioxidants / metabolism*
  • Dose-Response Relationship, Radiation
  • Fluoresceins
  • Fluorescent Dyes
  • Free Radical Scavengers / metabolism
  • Free Radical Scavengers / pharmacology
  • Free Radicals / metabolism*
  • Glutathione / metabolism*
  • Humans
  • Intracellular Fluid / metabolism
  • Keratinocytes / radiation effects
  • Oxidation-Reduction
  • Rhodamines / pharmacology
  • Tumor Cells, Cultured
  • Ultraviolet Rays


  • Antioxidants
  • Fluoresceins
  • Fluorescent Dyes
  • Free Radical Scavengers
  • Free Radicals
  • Rhodamines
  • dihydrorhodamine 123
  • diacetyldichlorofluorescein
  • Glutathione
  • Acetylcysteine