Fig. 4. Simulated microgravity (s-μG) decreases myotubular dimensions of engineered muscle tissues (EMTs).

a Representative image of myotubes in EMTs in standard gravity controls (ctrl) and s-μG. Scale bar: 50 μm. b Representative image of EMT cross-sections in controls and s-μG. Scale bar: 50 μm. c Average transverse diameter of myotubes. d Average length of myotubes. e Fusion index of skeletal myoblasts. f Number of myotubes in unit cross-sectional area (mm²). Diameter, and length of myotubes, and fusion index of myoblasts of EMTs developed in s-μG for 5 days are significantly lower than controls. Myotube density throughout the EMT cross-section shows no statistical significance. Data are mean ± SEM (c, d N = 200 myofibers, e, f N = 4 EMTs, ^*P < 0.05, ^***P < 0.001, ns = no significance by unpaired t test, solid and dotted lines in the violin plots represent means and quartiles respectively).