Western blot analysis of dystrophin expression in GRMD canines treated with rAAV6-U7-ESE6/8. For analysis, biopsies were collected from the LVFW and IVS from base to apex as depicted in Figure 1a. Normal, untreated unaffected canine (positive control); untreated, untreated affected GRMD canine (negative control). (a) Representative blots are shown from GRMD canines treated with either 1.8 × 1012 gc/kg of rAAV6-U7-ESE6/8 (GRMD 1, GRMD 2) or 1.4 × 1013 gc/kg of rAAV6-U7-ESE6/8 (GRMD 3, GRMD 4) and euthanized 13 months later. Note that a greater number of samples were positive for dystrophin following treatment with high-dose rAAV6 compared to low-dose rAAV6. (b) Quantitative, densitometric analysis of each western blot was performed. Dystrophin expression was higher in GRMD canines treated with high-dose rAAV6 (15–20% of normal) versus low-dose rAAV6 (3–5% of normal). AAV, adeno-associated virus; Dys, dystrophin; GAPDH, glyceraldehyde 3-phosphate dehydrogenase; GRMD, golden retriever muscular dystrophy; IVS, interventricular septum; LVFW, left ventricular free wall; rAAV6, recombinant AAV6; Untr, untreated GRMD canine.