Fig. 2

Early regeneration of skeletal muscle is impaired in ΔKlotho mice. a The right TA muscle from ΔKlotho and control mice was injured by injection of cardiotoxin (CTX) at p50 and isolated at p60. b TA muscles (arrows) show extensive fibrosis in ΔKlotho mice 10 days (d10) after injury. c Representative H&E stainings and Alizarin Red stainings of TA muscle cross-sections at d10 after injury. Necrotic tissue, fatty vacuoles, and massive cell invasion are visible in ΔKlotho TA muscles, while control TA muscles show mostly regenerating myofibers. Scale bar = 100 μm. d Immunostainings of cross-sections of TA muscles at d10 after injury with antibodies directed against Laminin (green) and developmental (dev) MHC (red), nuclei are stained with DAPI (DNA, blue). Scale bar = 50 μm. e Minimal fiber feret measured on whole cross-sections from ΔKlotho and control TA muscles at d10 after injury. (ΔKlotho n = 4 mice, control n = 5 mice). Proportion of f devMHC-positive fibers and g Pax7-positive cells per myofiber on whole cross-sections at d10 after CTX-induced injury (ΔKlotho n = 3 mice, control n = 4 mice). h Representative images of stainings for CD68 (in red) and laminin (in green) showing increased infiltration with macrophages in regenerating muscles from ΔKlotho mice. Scale bar = 50 um. All data are presented as means ± SEM. *p < 0.05, **p < 0.01, ***p < 0.001