Glutathione (GSH) exists in mammalian tissues in vivo at high concentrations and plays an important protective role against oxidatively induced damage to biological molecules including DNA. We investigated oxidatively induced damage to DNA by GSH depletion in different organs of rabbits in vivo. Rabbits were treated subcutaneously with buthionine sulfoximine (BSO), an effective GSH-depleting compound. GSH levels were measured in heart, brain, liver and kidney of animals. BSO treatment significantly reduced GSH levels in heart, brain and liver, but not in kidney. DNA was isolated from these tissues to determine whether GSH-depletion causes oxidatively induced DNA damage in vivo. Gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry with isotope dilution were applied to measure typical products of oxidatively induced damage in isolated DNA samples. Several such products were identified and quantified in all organs. BSO treatment caused significant formation of 8-hydroxyguanine, 2,6-diamino-4-hydroxy-5-formamidopyrimidine, 8-hydroxyadenine and (5S)-8,5-cyclo-2-deoxyadenosine in DNA of organs of rabbits. Animals were fed with the semi-essential amino acid 2-aminoethanesulfonic acid (taurine) during BSO-treatment. Taurine significantly inhibited GSH-depletion and also formation of DNA products. Depletion of GSH correlated well with formation of DNA products, unequivocally proving the role of GSH in preventing oxidatively induced DNA damage. Our findings might contribute to understanding of pathologies associated with DNA damage, oxidative stress and/or defective antioxidant responses.
Pub Type: Journals
8, 5'-Cyclo-2'-deoxyadenosine, Glutathione depletion, Hydroxyl radical, Mass spectrometry, Oxidative DNA damage