FIG. 2.

Mice with moderate overexpression of SIRT1 are more resistant to liver damage during acute APAP treatment. Overnight fasted wild-type (SIRT1-WT) and mice overexpressing SIRT1 (SIRT1-Tg) were i.p. injected physiological saline (vehicle) or 300 mg/kg APAP. Mice were sacrificed after 3, 6, or 24 h, as indicated, and livers and serum were collected. (A) Left panels, SIRT1 protein levels detected in liver extracts derived from SIRT1-WT or SIRT1-Tg mice sacrificed before APAP or vehicle injection. Blots were quantified and results are expressed as fold change relative to SIRT1-WT mice. Values are mean ± SEM. ***p < 0.001 versus SIRT1-WT mice according to Student's t-test. n = 5 mice per genotype. Right panels, Immunoblots showing SIRT1 protein levels in liver extracts from SIRT1-WT and SIRT1-Tg mice treated with APAP or saline for 6 h. α-Tubulin was used as loading control. Densitometric quantification depicts SIRT1 protein levels in each condition. After quantification of all blots, results are expressed as fold change relative to the vehicle-injected condition and are mean ± SEM. Statistical analysis was performed by one-way ANOVA followed by Bonferroni post hoc test. ***p < 0.001 versus each vehicle-injected control. ^###p < 0.001 versus APAP-injected SIRTI-WT mice. n = 6–8 mice per group. (B) Images of hematoxylin and eosin staining of liver sections from wild-type and SIRT1-Tg mice treated with APAP or saline for the indicated times. Scale bars = 200 μm. n = 5 mice per group. (C) Plasma ALT levels measured in the same experimental conditions. Values are mean ± SEM. Statistical analysis was performed by one-way ANOVA followed by Bonferroni post hoc test. ***p < 0.001 versus control (vehicle) condition. ^##p < 0.01, ^###p < 0.001 versus SIRT1-WT mice. n = 6–8 mice per group. (D) Images of TUNEL staining and quantification of TUNEL-positive cells analyzed 24 h after APAP injection. Scale bars: 100 μm. Values are mean ± SEM. Statistical analysis was performed by one-way ANOVA followed by Bonferroni post hoc test. *p < 0.05, ***p < 0.001 versus control (vehicle) condition. ^###p < 0.001 versus SIRT1-WT. n = 5 mice per group. ALT, alanine transaminase. To see this illustration in color, the reader is referred to the web version of this article at www.liebertpub.com/ars