Figure 2
From: Oxidative stress, mitochondrial damage, and cores in muscle from calsequestrin-1 knockout mice
Structural abnormalities in EDL muscle fibers from aged CASQ1-null mice. (A) Many fibers (even at 19 months of age) do not present severe disarrangement of contractile elements. Nevertheless, even in these fibers, normal muscle ultrastructure is not well preserved, with partial misalignment of myofibrils and frequent mitochondria exhibiting clear signs of structural damage/swelling (arrowheads, see also inset). (B, C) Unstructured cores, areas in which Z lines ((B), small arrows) and contractile elements are out of register and sarcomeres are partially disarranged, are frequently observed in fibers from EDL muscle from CASQ1-null mice. Z-line streaming is also present in some fibers ((C), empty arrows). (D) Contracture cores, areas of excessive sarcomere shortening, contain fewer and severely damaged mitochondria (inset). See Figure 1 and Additional file 3: Table S1 for detailed quantitative analyses. Scale bars: (A, B), 1 μm; (C, D), 0.5 μm; insets, 0.1 μm. EDL, extensor digitorum brevis; CASQ1, skeletal isoform of calsequestrin.