Figure 2. Arg-ii-/- mice reveal protection against age-associated sarcopenia (muscle fiber cross-sectional area, CSA). (A) Representative images of soleus sections stained for nuclei with DAPI (blue) and skeletal sarcolemma with WGA (green) in young and old wild type (wt) and arg-ii-/- (ko) male mice. Scale bar: 100 µm. (B–E) left panels present quantification of CSA in µm2 of soleus and tibialis, in male and female mice, while the right panels present the fold change in CSA based on the ratio of old/young reflecting the age-dependent reduction of CSA. Combined parametric one-way ANOVA and unpaired t-test with Welch’s correction were applied; n = 4–7 mice for each group. *p < 0.05, **p < 0.01, ***p < 0.001 between the indicated groups.