FIG. 3.

Moderate overexpression of SIRT1 contributes to reduction in oxidative stress by improving the antioxidant capacity during APAP treatment. Overnight fasted SIRT1-WT and SIRT1-Tg mice were i.p. injected physiological saline (vehicle) or 300 mg/kg APAP and sacrificed after the indicated times. (A) GSH/GSSG ratio, protein carbonyl content, and APAP-Cys adducts were analyzed in livers from SIRT1-WT and SIRT1-Tg mice treated with APAP for 6 and 24 h. Values are mean ± SEM. Statistical analysis was performed by one-way ANOVA followed by Bonferroni post hoc test. **p < 0.01, ***p < 0.001 versus each control (vehicle) condition. ^##p < 0.01, ^###p < 0.001 versus SIRT1-WT mice. n = 6–8 mice per group. (B) Immunoblot analysis of catalase and MnSOD levels in total liver extracts from SIRT1-WT and SIRT1-Tg mice 6 h after APAP injection. p85α was used as a loading control. After quantification of all blots, results are expressed as fold change relative to the saline-injected condition and are mean ± SEM. Statistical analysis was performed by one-way ANOVA followed by Bonferroni post hoc test. **p < 0.01, ***p < 0.001 versus vehicle-injected mice. ^#p < 0.05, ^##p < 0.01 versus SIRT1-WT mice. n = 6–8 mice per group. (C) Nuclear levels of Sp1 are increased by APAP in wild-type mice and this effect was attenuated in SIRT1-Tg mice. Representative immunoblots showing nuclear Sp1 and Lamin B as a loading control. After quantification of all blots, results are expressed as fold change relative to vehicle condition and are mean ± SEM. Statistical analysis was performed by two-way ANOVA followed by Bonferroni post hoc test. **p < 0.01, ***p < 0.001 versus control (vehicle) condition. ^##p < 0.01, ^###p < 0.001 versus SIRT1-WT mice. n = 5–6 mice per group. GSH, glutathione; MnSOD, manganese superoxide dismutase; Sp1, specific protein 1.