Figure 3.

Effects of AdipoRon on fibre type composition and lipid infiltration in soleus and EDL from middle‐aged obese mice. Fibre typing and Bodipy staining were performed on serial muscle cross‐sections in an oxidative (soleus) and a glycolytic (EDL) muscle. (A) Fibre typing was carried out by immunofluorescence staining of different myosin heavy chains isoforms (MyHCs). Type 1 fibres were labelled in blue, type 2a in green, 2x in red while 2b were nonlabelled (black). Laminin antibody was used to delineate basal membrane (white). Representative sections for each group are shown. Scale bar = 200 μm. Insets: Higher magnification of immunostaining images (scale bar = 50 μm). (B) Fibre type proportion for each muscle in the 4 groups of mice. Data are means for six mice per group. Statistical analysis was performed using one‐way ANOVA followed by Tukey's test (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. (C) Bodipy staining of lipids (red) on muscle cross‐sections to quantify IMCL content on a fibre type specific‐basis. Laminin was coloured in cyan. Peripheral (subsarcolemmal, SS) lipid droplets (LDs) are usually more abundant than central ones. Arrows indicate scalloped edges of sarcolemma facing large SS LDs. Representative sections for six mice per group are shown. Scale bar = 20 μm.