Fig. 5

Reduced myofiber size in ∆Ig3-MuSK soleus but not TA. WT and ∆Ig3-MuSK TA and soleus sections were stained with H&E (A, B), WGA (C, D), or anti-dystrophin (E, F). In the TA, the structure (A), WGA staining (C), and mean Feret diameters (G) were indistinguishable in both genotypes. Data are means ± SEM from three animals of each genotype. Average number of muscle fibers counted per animal 963 ± 77. Soleus WT and ΔIg3-MuSK stained with H&E (B), WGA (D), or dystrophin (F). Note that the overall structure of the muscle was comparable, but there is increased interstitial WGA signal in ΔIg3-MuSK soleus. Soleus myofiber Feret diameters of all fibers (H), type I fibers (I), or type IIa fibers (J) were reduced in ΔIg3-MuSK compared to WT. All fibers are as follows: 40.6 µm ± 0.2 WT and 38.4 µm ± 0.2 ∆Ig3-MuSK (697 fibers/animal ± 72, n = 3 animals), type I fibers: 36.6 µm ± 0.2 WT and 34.4 µm ± 0.2 ∆Ig3-MuSK (300 ± 33 fibers/animal, n = 4 animals), and type IIa: 36.7 µm ± 0.2 WT and 33.9 µm ± 0.2 ∆Ig3-MuSK (487 ± 50, fibers/animal n = 4 animals; ****p < 0.0001, Mann–Whitney test)