Figure 3. GTE- and cocoa-supplemented diets partially prevent the decrease in PGC-1α expression and restore mitochondrial depletion occurring muscles in the course of age. (A) Densitometric analysis of changes in PGC-1α levels in muscles from the three experimental conditions; data were normalized to α-tubulin. Bars represent the values (mean ± SEM) of 3 mice per condition from 2 independent western blot analysis; *p < 0.05 vs. control, two-way ANOVA (Bonferroni’s post-hoc test); red lines in graph indicate PGC-1α levels found in adult muscles. (B) Representative western blots of PGC-1α and α-tubulin (as loading control) proteins in TA and Sol muscles from mice of control (Ctrl), GTE and cocoa groups. (C) Quantification of ATP5A-immunoreactivity in TA muscles of control, GTE and cocoa groups; bars represent the values (mean ± SEM) of 3 mice per condition; **p < 0.01 and ***p < 0.001 vs. control, one-way ANOVA (Bonferroni’s post-hoc test). (D–F) Representative images showing a combined immunolabeling for laminin (lam, green) and ATP5A (red) in transversal cryosections of TA muscles from three experimental groups used for quantification, as indicated. Note the overt increase in ATP5A immunostaining after GTE (E) and, particularly, cocoa (F) supplementation compared to control (D). Arrow in (D) points out lipofuscin deposition in a myofiber. Scale bar in (F): 50 μm (valid for D, E).