MOE AOs induce effective exon skipping and dystrophin restoration in <i>mdx</i> mice by local intramuscular injection.

<p>(A) Immunohistochemistry for dystrophin induction in TA muscles of adult <i>mdx</i> mice 2 weeks after one single intramuscular injection of 5 µg MOE25(PS), MOE25(PO), MOE20(PS) and 2′OmePS AOs (scale bar = 100 µm). (B) Quantitative evaluation of total dystrophin-positive fibres in TA muscles treated with MOE and 2′OmePS AOs at 2 weeks after a single injection. The data shows that MOE25(PS) AOs restored significantly higher number of dystrophin-positive fibres than those of other AOs and significant difference was observed for all tested AOs compared with untreated <i>mdx</i> control (*p<0.05). (C) RT-PCR to detect exon skipping efficiency at the RNA level demonstrated up to 10% exon 23 skpping in the TA muscle treated with MOE25(PS) AOs at 2 weeks after injection. This is shown by shorter exon skipped bands (indicated by Δexon23 for exon 23 skipping). (D) Western blot analysis for treated TA muscles at 2 weeks after one single intramuscular injection of MOE and 2′OmePS AOs. Total protein was extracted from TA muscles of adult <i>mdx</i> mice treated with different AOs and untreated control. Fifty microgram of total protein from untreated <i>mdx</i> mice TA muscles and treated muscle samples was loaded. Five microgram of total protein (10%) from <i>C57BL6</i> TA muscles was loaded as a normal control. No visible difference in the size of dystrophins between muscles treated with AOs and muscle from the normal <i>C57BL6</i> mouse. α-actinin was used as loading control.