Fig. 4.

Human DEC (1 × 10⁶ and 5 × 10⁶) administration improves muscle morphology via normalized fiber size and homogeneity in the heart, diaphragm and gastrocnemius muscle at 180 days after systemic DEC administration. Representative histology images of Hematoxylin and Eosin (H&E) stained cross-sections of the cardiac (A), diaphragm (C) and gastrocnemius muscle (E) of mdx/scid mice at 180 days after systemic-intraosseous administration of DEC therapy compared with vehicle-injected and WT controls. Magnification 40x, scale bar 50 μm (heart); magnification 20x, scale bar 100 μm (diaphragm and gastrocnemius muscle), n = 3/group, 12 ROI/organ/mouse (B) Feret’s diameter measurements in the heart revealed a right-ward shift in fiber size distribution towards larger fibers in both DEC injected groups, bars represent means ± SEM. (D) Fiber size in the diaphragm was increased after DEC therapy when compared to vehicle controls, bars represent mean ± SEM. (F) In the gastrocnemius muscle there was a significant increase in the fiber size of DEC-injected compared to vehicle injected mice specifically in the fiber size increment between 30-35 µm. Fibers diameters were marked with black arrows. Data presented as mean ± SEM. Two sample t-test assuming unequal variances. *p < 0.05, **p < 0.01, *** p < 0.001, **** p < 0.0001