Fig. 6

Effects of single and repeated intravenous administration with an exon skipper PPMO (10 mg/kg, 4 times every 2 weeks) on EIM reactance in mdx mice. A The multifrequency data (10–1000 kHz) for EIM reactance in vehicle-treated WT mice (black line, n = 10), vehicle-treated (red line, n = 9), or PPMO-treated mdx mice (green line, n = 10) during the pre, 2W post-dose (2 weeks after the 1st administration), and 8W post-dose (2 weeks after the 4th administration) measurements. B Summarized 50 kHz EIM reactance before and after single and repeated administration of PPMO (Pre, 2W post-dose, and 8W post-dose). Statistical comparisons were performed using Student’s t-test with a closed testing procedure (^*p < 0.05, n.s.: not significant vs. the vehicle-treated WT mice group, ^#p < 0.05 vs. the vehicle-treated mdx mice group). C RT-qPCR for calculation of exon skipping efficiency in the GC muscle. D Capillary electrophoresis immunoassay using the Wes system for quantification of dystrophin protein levels in the GC muscle. The percentage of exon skipping efficiency was calculated using the following formula: expression level of exon 23 skipped / (expression level of exon 23 skipped + expression level of non-skipped) × 100. Dystrophin expression value was calculated as a percentage of WT mice dystrophin levels. N.D.: not detected. Data are represented as mean ± SEM. PPMO: peptide (Pip9b2)-conjugated antisense phosphorodiamidate morpholino oligomer, EIM: electrical impedance myography, WT: wild-type, RT-qPCR: real-time quantitative polymerase chain reaction, GC: gastrocnemius, SEM: standard error of the mean