Figure 3

Fast-twitch type 2 fibers are predominantly involved with strong aquaporin-4 (AQP4)-positive rimmed vacuoles (RVs) and TAR-DNA-binding protein-43 (TDP-43) aggregation. Immunohistochemical examination of myosin heavy chain-fast (MHCF) and myosin heavy chain-slow (MHCS) in serial sections (A-C, B is high-power view of A). Double immunofluorescence analysis of AQP4 and MHCF showed many RVs with intense AQP4 expression in the MHCF-positive fibers (D1-D3, arrow-heads). Occasionally, the RVs with AQP4 expression were detected in the MHCF-negative fibers (D1 and D3, arrows). Double immunostaining of AQP4 and MHCS showed that RVs with strong AQP4 expression were mostly located in the non-MHCS fibers (E1-E3, arrow-heads). Immunohistochemical analysis of TDP-43 (F). Double immunostaining of TDP-43 and MHCF revealed that the TDP-43 immunoreactivity is mostly present in MHCF fibers (G, arrows), not in the MHCS fibers (Fig. H).