Figure 5. Acute injury unmasks muscle pathology in young adult MyoD-iCre SmnF7/– mutants bearing 2 copies of the SMN2 gene.
(A) H&E-stained transverse sections of muscle from mutant and control mice examined 6, 14, and 26 days after injury with CTX. Note persistence of muscle pathology typified by hypotrophic fibers (solid arrowheads), numerous central nuclei (arrows), and degenerating fibers (open arrowheads) at day 26 in the mutant. Scale bars: 25 μm (upper panels), 15 μm (middle panels), and 30 μm (lower panels). Graphs depict the proportion of fibers with central or peripherally located nuclei in mutants and controls (B) 14 days and (C) 26 days after injury. ***P < 0.001, t test, n ≥ 400 fibers from n ≥ 4 mice of each genotype.