Fig. 1

Comparison of IMAT, myofiber size and collagen deposition between mouse strains and sex during muscle homeostasis. A Experimental outline. B Body weights (g) of male (M) and female (F) mice from C57BL/6J (Bl6), 129S1/SvlmJ (129S) & CD1 strains at 10 weeks of age. Data are grouped to compare between sexes within the same strain (Left); and within the same sex (Right). C Top: Immunofluorescence of Tibialis Anterior muscles (TAs) of uninjured Bl6, 129S & CD1 females and males to visualize PERILIPIN⁺ adipocytes (green). Nuclei are marked by DAPI (magenta). Scale bar: 500 µm. Middle: Individual muscle fibers, stained by PHALLOIDIN and false color-coded according to size (µm²). Scale bar: 250 µm. Bottom: Collagen deposition (red) is detected by the histological stain Sirius Red. Scale bar: 250 µm. D Quantification of IMAT normalized to area of uninjured TA (adipocytes/mm²). E Average cross-sectional area (CSA) of total myofibers (µm²). F Average CSA of total myofibers normalized to body weight (µm²/g). G Quantification of area occupied by collagen deposition normalized to total TA area (%). D-G Top: Data are grouped to compare between sexes within the same strain. Bottom: Data are grouped to compare between strains within the same sex. All data are represented as mean ± SEM. An unpaired two-tailed t test or a one-way ANOVA followed by a Dunnet’s multiple comparison was used. A p value less than 0.05 was considered statistically significant where: * p ≤ 0.05, ** p ≤ 0.01, *** p ≤ 0.001 and **** p ≤ 0.0001