Fig. 6

Restoration of dystrophin in tibialis anterior muscles of mdx mice (aged 4–5 weeks) 2 weeks after intramuscular injection with 10 μg polymer formulated PMOE23 (2 μg) in 40 μL saline. Muscles treated with PMOE23 only was used as controls. a Dystrophin was detected by immunohistochemistry with rabbit polyclonal antibody P7 against dystrophin. Blue nuclear staining with 4,6-diamidino-2-phenylindole (original magnification ×200; scale bar 200 µm). b The percentage of dystrophin-positive fibers (mean ± SD, n = 5, Two-tailed t-test, *p ≤ 0.05 compared with PMO). c Detection of exon 23 skipping by RT-PCR. Total RNA of 100 ng from each sample was used for amplification of dystrophin mRNA from exon 20 to exon 26. The upper bands (indicated by E22 + E23 + E24) correspond to the normal mRNA, and the lower bands (indicated by E22 + E24) correspond to the mRNA with exon E23 skipped