All 5-aa core Pip6-PMO-treated mice exhibited high dystrophin intensity values in the heart with the exception of Pip6e (other Pip6-PMOs were statistically significant compared to mdx = P < 0.0001; Table 1 ). Pip6a-and Pip6b-PMO conjugates displayed the highest recovery scores, as observed in Figure 4b (%RS 37.66% and 34.22%, respectively) closely followed by Pip6f-PMO (%RS 26.24%) and then Pip5e-PMO (%RS 17.32%). When directly compared to Pip5e-PMO treatment, only Pip6a-PMO was significantly better in the heart ( Table 2 ). These 5-aa core Pip6-PMOs were also shown to restore other dystrophin complex proteins, namely neuronal nitric oxide synthase, α-sarcoglycan, and β-sarcoglycan as illustrated by immunohistochemical staining in the TA muscle (Supplementary Figure S4) .