Figure 6.

Quantification of mitochondrial content in muscle of middle‐aged obese mice treated or not with AdipoRon. (A) Mitochondrial content was assessed by immunodetection of the translocase of outer mitochondrial membrane 20 (TOMM20) in soleus and EDL from the four groups of mice on a fibre dependent manner. Representative images for each group are shown. Scale bar = 20 μm. (B) Quantification of mitochondrial content in peripheral (subsarcolemmal) and central (intermyofibrillar) subcellular regions for each fibre type in soleus or EDL. Mitochondrial content in each region was expressed as the percentage of stained area normalized to total fibre area. Data are means ± SEM for 5–6 mice per group. Statistical analysis was performed by one‐way ANOVA (comparing three groups of O‐mice) or by unpaired two‐tailed t‐test (Y‐ND vs. O‐ND). ^$ P < 0.05 versus Y‐ND mice. *P < 0.05, **P < 0.01 versus O‐ND mice. Symbols for differences among central regions are in dark green, among peripheral regions in light green, and those for the total content in black. (C) Lipid droplet (LD)‐mitochondrion contacts. Left, confocal fluorescence micrographs of soleus from an O‐HFD mouse: LDs were stained with Bodipy in red, mitochondria with anti‐TOMM20 in green, the edge of the fibre with anti‐laminin in cyan and nuclei with DAPI in blue. Some mitochondria co‐localized with LDs when channels were merged. Scale bar = 10 μm. Inset: Higher magnification (scale bar = 5 μm). Right, transmission electron micrograph of rectus femoris from an O‐HFD + AR mouse illustrating LD‐mitochondrion contact. Scale bar = 1 μm (top right) and 0.25 μm (inset, bottom right).