Fig. 2.

Increased oxidative stress in tissues of progeroid Ercc1^-/Δ mice and old WT mice. (a) Levels of four cyclopurine lesions (R-cdG, S-cdG, R-cdA, S-cdA) measured in liver tissues of 4-month-old WT, Xpa^-/- and Ercc1^-/Δ mice (n = 3 per genotype) by LC-MS/MS/MS. (b) Detection of endogenous superoxide production by quantifying 2-OH-E⁺ by HPLC/electrochemical analysis in DHE-treated kidney (n = 3–7) and liver (n = 6–9 animals per genotype/age). (c) Representative images from immuno-spin trapping of endogenous, biomolecular free radicals with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). The level of oxidant stress was determined by immunodetection of DMPO-adducted biomolecules in renal and liver sections. DMPO staining is illustrated in red, actin in green to illustrate tissue architecture and DAPI in blue to highlight cell nuclei. (d) Lipid peroxidation as measured by quantitation of 4-hydroxynonenal protein adducts via ELISA (n = 3–4 mice per group). For all panels, values represent the mean ± SD, *p < 0.05, **p < 0.01, ***p < 0.001 determined by one-way ANOVA with Tukey's test.