Figure 2: Improvement of pathological pattern in the cMD1-expressing muscles.

After killing, two muscles (the flexor carpi ulnaris muscle and the extensor carpi radialis muscle) in each forelimb of each GRMD dog injected by the LR route either with the rAAV2/8-Spc5.12-cMD1 vector (n=4 dogs and 16 muscles analysed) or with buffer (n=3 dogs and 12 muscles analysed) were analysed. Myofibre regeneration was evaluated by immunohistochemical staining of myofibres using an antibody specific for developmental myosin heavy chain isoform. Total and endomysial fibrosis were evaluated by immunohistochemical detection of Collagen I. (a) Regeneration and fibrosis immunostaining on transverse sections of muscle samples. Representative results are presented for two muscles of dog LR1 (noninjected forelimb and injected forelimb). The levels of cMD1-positive fibres detected by immunostaining from the same muscle samples are indicated above each panel. Scale bar, 100 μm. (b) Regeneration, total fibrosis and endomysial fibrosis quantification in the total of 28 muscles analysed in the GRMD dogs injected by the LR route, either with the rAAV2/8-Spc5.12-cMD1 vector or with buffer was done using an automatic measurement of the percentage of the labelled area after selection of regions of interest. Analyses were done according to the percentage of cMD1-positive fibres of each muscle: <12% (n=20, empty symbols), between 30 and 45% (n=4, grey full symbols) and between 46 and 90% (n=4, black full symbols). Each point represents the data obtained in one muscle, and the horizontal bars represent the mean of the values obtained for each group *P<0.05 (nonparametric Kruskal–Wallis test with post hoc multiple comparison Dunn’s test).