No dystrophin expression was detected in cardiac and skeletal muscles of <i>Dmd^mdx</i> rats.

<p>(<i>A</i>) Male 7 month-old rats of line 61, wild-type littermate controls (WT) and <i>Dmd^mdx</i> were sacrificed and biopsies from <i>tibialis cranialis</i> muscles (TC) and hearts (H) were harvested. Western-blot of total proteins (50 µg) was incubated with NCL-DYS2 and Manex1011C monoclonal antibodies (C-terminal and exons 10/11 epitopes, respectively). This revealed undetectable levels of the 427 kDa dystrophin band in line 61 <i>Dmd^mdx</i> rats. Muscle from a GRMD dog (GD) was used as negative control and samples from WT rats were used as positive controls. Staining with an anti-GAPDH polyclonal antibody validated equal protein loadings. (<i>B–E</i>) Heart and <i>biceps femoris</i> muscles from the same wild-type (<i>B</i> and <i>C</i>) and <i>Dmd^mdx</i> rats (<i>D</i> and <i>E</i>) were assessed for dystrophin expression using immunohistochemistry with Mandys110 monoclonal antibody (against exons 38–39 epitope). Compared to the subsarcolemmal expression of dystrophin in wild-type muscles, no dystrophin was detected in <i>Dmd^mdx</i> rats except for the presence in skeletal muscle of only rare scattered revertant positive fibers (arrowheads). Immunolabelling of dystrophin (<i>B–E</i>) Bar = 100 µm.