Fig. 10: Morphometric and functional analysis of skeletal muscles of nude mice following foetal thymus transplantation.

Representative images of H&E and AM staining of TAs from nude, Tnu^E17MDX, Tnu^E17C57Bl mice (a). Quantification of the relative frequency of the myofiber CSA expressed as the frequency distribution of TA muscles of nude, Tnu^E17MDX, Tnu^E17C57Bl mice (Tnu^E17C57Bl: minimum, median, maximum and range: 98.07, 1763, 8676, 8578, respectively; 25% percentile, 75% percentile, coefficient of variation: 1231, 2434, 47.44%, respectively. Tnu^E17MDX: minimum, median, maximum and range: 81.53, 1421, 5449, 5367 respectively; 25% percentile, 75% percentile, coefficient of variation: 962.9, 2021, 51.27%, respectively. nude: minimum, median, maximum and range: 101.7, 1461, 8946, 8845, respectively; 25% percentile, 75% percentile, coefficient of variation: 982.2, 2029, 54.19%, respectively) (b). Quantification of fibrotic areas of TA muscles of nude, Tnu^E17MDX, Tnu^E17C57Bl mice (mean area: nude: 4.534; Tnu^E17MDX: 4.850; Tnu^E17C57Bl: 4.055) (c). For morphometric analysis, images were quantified with ImageJ software for each mouse. Tetanic force of TA of Tnu^E17MDX is dramatically decreased compared to nude and Tnu^E17C57Bl mice (d). Weight of mice following E17 thymus transplantation is reported in the graph (e). Representative immunostaining with dys-2 (C-terminal-domain) antibody showed weak dystrophin intensity around the myofibers in TA of Tnu^E17MDX (f). Representative image of RT-PCR analysis described lower expression of Dp427 dystrophin isoform in TA of Tnu^E17MDX compared to nude and Tnu^E17C57Bl mice (g). ALT, AST and CK are measured in the serum of nude, Tnu^E17MDX, Tnu^E17C57Bl mice (h). RT-qPCR experiments on TA muscles of nude, Tnu^E17MDX, Tnu^E17C57Bl mice showed differences of expression of genes specifically involved in inflammation/fibrosis and atrophy (i); skeletal muscle metabolism (j); mitochondrial biogenesis (k) and oxidative capacity (l). Scale bar: 200 and 40 μm for higher magnification images in the inserted squares (a); 50 μm (f). The comparisons among the averages of the groups were evaluated using one-way ANOVA (b–l). b **p = 0.0017 and ****p < 0.0001. c **p = 0.0090. d ****p < 0.0001. g *p = 0.0282 Tnu^E17MDX vs Tnu^E17C57Bl; **p = 0.0013 Tnu^E17MDX vs nude; *p = 0.0459 Tnu^E17C57Bl vs nude. h AST: *p = 0.0459 Tnu^E17MDX vs Tnu^E17C57Bl; *p = 0.0228 Tnu^E17MDX vs nude; ALT: **p = 0.0018 Tnu^E17MDX vs Tnu^E17C57Bl; **p = 0.0027 Tnu^E17MDX vs nude. i MurF1 ː ***p = 0.0001, **p = 0.0011; RORγtː ****p < 0.0001; IL-1β: *p = 0.0174 Tnu^E17MDX vs Tnu^E17C57Bl; **p = 0.0094 Tnu^E17MDX vs nude; RelBː *p = 0.0110 nude vs Tnu^E17MDX; *p = 0.0203 Tnu^E17MDX vs Tnu^E17C57Bl. j PDK4: **p = 0.0031 and **p = 0.0003; GP-x1: *p = 0.0431 Tnu^E17MDX vs Tnu^E17C57Bl, *p = 0.0231 Tnu^E17MDX vs nude; PPARαː **p = 0.0047 Tnu^E17MDX vs Tnu^E17C57Bl, **p = 0.0099 Tnu^E17MDX vs nude. k PGC1αː *p = 0.0489; NRF-1: **p = 0.0045 Tnu^E17MDX vs Tnu^E17C57Bl, **p = 0.0078 Tnu^E17MDX vs nude. l CoxVa: *p = 0.0295; CoxVIIb: **p = 0.0011 Tnu^E17MDX vs Tnu^E17C57Bl; **p = 0.0052 Tnu^E17MDX vs nude. Data are presented as mean ± SD of three independent experiments with n = 3 (b–d); n = 4 (e); n = 3 (f–h); n = 3 with two technical replicates (RelB, IL-1β, RORγt) and with two/three technical replicates (murf-1) each (i); n = 3 with two technical replicates (GP-x1, pparα) and with two/three technical replicates (pdk-4) each (j); n = 3 with two technical replicates (k) mice/group. Source data are provided as a Source Data file.