Biodistribution, RNA, and protein analysis of mdx/utrn+/– and mdx mice treated for 6 months. (a) Biodistribution analysis. (b) Reverse transcription-PCR (RT-PCR) analysis of muscle samples from mdx and mdx/utrn+/– mice. Exon 23 skipping could be confirmed for all samples. G is gastrocnemius, Q is quadriceps, TA is tibialis anterior, T is triceps, H is heart, D is diaphragm, C is negative control. The skip product is smaller than the wild-type fragment and thus binds less ethidium bromide, hampering visual estimation of skipping percentages. (c) Lab-chip analysis of exon skipping percentages. (d) Western blot analysis of gastrocnemius protein lysates of mdx mice treated for 3 or 6 months (3 m and 6 m, respectively) and mdx/utrn+/– mice treated for 6 months. NT, not treated. α-Actinin staining was used to confirm equal loading. (e) Quantification of dystrophin levels for gastrocnemius. Error bars show the SD. *P value <0.05.