Impaired activity tolerance and skeletal muscle morphology in DTG mice.

<p>(A) Cage activity and (B) voluntary running wheel activity over 24 hrs of 11-wk-old WT, DN-AMPKα2, UCP1-TG and DTG mice (n = 6–10 per group). (C) Representative H&E staining of <i>M. tibialis anterior</i> (TA) muscle from 20-wk-old WT, DN-AMPKα2, UCP1-TG and DTG mice showing progressive muscle degeneration, including central nuclei (black arrows) in DTG mice, (scale bars 50 µm). (D) Quantification of cross-sectional area (CSA) of myofibers (n = 3 per group). (E) Gene expression analysis of muscle fiber-type markers in <i>Quadriceps</i> muscle of 12-wk-old WT, DN-AMPKα2, UCP1-TG and DTG mice by quantitative RT-PCR (n = 8 per group). Means with different letters are significantly different (1way ANOVA and Bonferroni's multiple comparisons test, p<0.05).