Age-dependent increases in the oxidative damage of DNA, RNA, and their metabolites in normal and senescence-accelerated mice analyzed by LC-MS/MS: Urinary 8-oxoguanosine as a novel biomarker of aging

► We developed an LC-MS/MS method for determinations of 8-oxo-dGsn and 8-oxo-Gsn. ► Oxidative DNA and RNA damage increased with aging in SAMR1 and SAMP8 mice. ► There were tissue-specific patterns in the basal level of DNA and RNA oxidation. ► The ratios of 8-oxo-Gsn to 8-oxo-dGsn in urine were much higher than in tissues.