Figure 4.

AT-GAA Improved Muscle Quality and Architecture in KO Mice

Muscle biopsies were collected from age and sex-matched WT, untreated (KO), and AT-GAA-treated KO (KO-ERT) mice. The samples were analyzed by second harmonic generation (SHG) and two-photon-excited fluorescence (2PEF) imaging. SHG reveals the position and organization of myosin heavy chain, while (2PEF) reveals mitochondria and autofluorescent particles. Every fiber from untreated KO mice (n = 3) show long longitudinal interruptions of the SHG image filled with 2PEF-positive particles (arrows); these areas correspond to the space occupied by the autophagic buildup. In contrast, most fibers from the treated KO mice (n = 3) do not show this defect; nevertheless, small interruptions of the SHG images can be seen in some fibers (arrows). Note that most fibers from treated mice have a larger diameter compared to that in untreated KO. Scale bars, 25 μm.