Reduced antioxidant capacity in progeroid Ercc1-/Δ mice and old WT mice. (a) Liver metabolite string analysis of 3-month-old WT (n = 6) versus Ercc1−/Δ mice (n = 7). Metabolites shaded in blue are significantly more abundant in the mutant animals. (b) Unbiased differential proteomic analysis of liver from 5 to 8-month-old adult WT, 25–30-month-old aged WT and 4-month-old progeroid Ercc1−/Δ mice (n = 4–8) revealed a significant decrease in the abundance of antioxidant proteins. (c) Catalase activity in the liver of Ercc1−/Δ and WT mice at various ages (n = 3–5 per group). (d) Cytosolic and (e) mitochondrial superoxide dismutase (SOD) activity in the liver of Ercc1−/Δ and WT mice at various ages (n = 3 per group). (f) The ratio of oxidized glutathione to reduced glutathione (GSH/GSSG) in livers from Ercc1−/Δ and WT mice of various ages (n = 3–14 per group). Values represent the mean ± SD, *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 determined by one-way ANOVA with Tukey’s test.