DMD myoblasts form fewer, smaller, and more immature myotubes. (A) Representative D3 healthy and DMD tissues (i and ii) and D6 healthy and DMD tissues (iii and iv) immunostained for SAA (black) and nuclei (blue). Bars, 50 µm. (B) Myotube density is plotted. (C) Myotube diameter is plotted. (D) The SAA/actin area ratio is plotted for D3 and D6. (E) SPD is plotted. The D3 DMD condition did not have significant enough SAA expression for statistical comparison. (F) Schematic representation of healthy (i) and DMD (ii) tissues and a summary of results. Unfused myoblasts are represented in red, and fused myotubes are represented in pink. For all data in this figure, n = 5 coverslips, 10 FOVs (318.5 × 318.5 µm) per sample, for each condition, for each day. *, P < 0.05 relative to D3 within a condition; **, P < 0.05 relative to the DMD condition on the corresponding day; #, P < 0.05 relative to the other day within a condition and to the other condition on the corresponding day. Error bars represent mean ± SEM.