Fig. 2: MyoAAV-UA mediates long-term improvement of dystrophic phenotypes in mdx mice via utrophin upregulation.

a Experimental timeline depicts MyoAAV-UA systemic injection and subsequent muscle biopsy time points in mdx mice. b, c Immunoblots of utrophin and dystrophin in biceps brachii (BB) and diaphragm (DIA) from different groups at 8 weeks (b) and 6 months (c) post-MyoAAV-UA injection. Vinculin was used as a loading control. d, e Quantification of utrophin protein levels in BB (d) and DIA (e) were normalized to vinculin (n = 6 mice in each group). f, g Quantification of utrophin mRNA expression level in BB (f) and DIA (g) at 8 weeks and 6 months post-MyoAAV-UA injection, normalized to Gapdh (n = 6 mice in each group). h, k Representative immunofluorescence staining of utrophin in BB, QD, and DIA muscles at 8 weeks and 6 months post-MyoAAV-UA injection. Scale bar, 100 µm. i, l Representative H&E staining of BB, QD, and DIA muscles at 8 weeks and 6 months post-MyoAAV-UA injection. Scale bar, 100 µm. j, m Representative Sirius Red staining of BB, QD, and DIA muscles at 8 weeks and 6 months post-MyoAAV-UA injection. Scale bar, 100 µm. n Statistical analysis of centrally nucleated myofibers in BB and QD (n = 6 mice in each group). o, p Statistical analysis of the fibrotic area percentage, indicated by red in Sirius Red-stained sections of BB and QD (o), and DIA (p) (n = 6 mice in each group). q Serum creatine kinase levels in different groups at 8 weeks and 6 months post-MyoAAV-UA injection (n = 6 mice in each group). b, c, h–m the experiment was repeated with six biologically independent replicates with similar results. d–g, n–q data are presented as mean ± s.d (n = 6 biologically independent experiments). Statistical analysis was performed using one-way ANOVA followed by Dunnett’s post hoc test. BB biceps brachii, QD quadriceps, DIA diaphragm. Source data are provided as a Source Data file.