EPC transplantation improves muscular morphology in the ischemic hind limb of diabetic mice on day 7. (A) Hematoxylin and eosin staining. The upper panels show representative photomicrographs of muscle fiber morphology of normal (N), ischemic (I), ischemic-diabetic-saline (I/D/S), and ischemic-diabetic-EPC (I/D/EPC) mice, while the lower panel shows the mean area of the muscle fibers n=4 per group. *P<0.05 for I versus N mice. †P<0.05 for D/I/EPC versus D/I/S mice. Scale bar=100 μm. (B) Electron micrographs showing extensive disorganization of the muscle fibers in the ischemic or ischemic diabetic groups compared with the normal group and less disorganization in the EPC-treated group. The arrows indicate damage to the Z-disc. (C) Higher magnification electron micrographs showing Z disk damage (arrow), large vacuoles (v), autophagosomes (A), disrupted mitochondria (double arrows), dilation of the sarcoplasmic reticulum (arrowhead), and dis-alignment of myofibrils in D/I/S mice. The Z disks (arrows) in the D/I/EPC group were improved better than those in the D/I/S. Scale bar=500 nm.