Dystrophin expression pattern and morphological examination of del52hDMD/<i>mdx</i> mouse lines.

<p><b>A</b>) Western blot analyses of heart and quadriceps, incubated with either GTX (human and mouse specific) or Mandys106 (human specific). Wild type expression levels of human dystrophin were observed in hDMD/<i>mdx</i> mice. Notably, del52hDMD/<i>mdx</i>#37 mice expressed traces of human dystrophin, in both cardiac and skeletal muscle, while this was not observed in del52hDMD/<i>mdx</i>#35 and <i>mdx</i>(BL6) mice. <b>B</b>) Sections of the heart and quadriceps stained with human specific dystrophin antibodies. Expression of human dystrophin is at wild type level in hDMD/<i>mdx</i> mice as anticipated. Both C57BL/6J, <i>mdx</i>(BL6) and del52hDMD/<i>mdx</i>#35 mice did not express human dystrophin. Interestingly, in most fibers of del52hDMD/<i>mdx</i>#37 mice, human dystrophin was expressed at low levels. Haematoxylin and eosin staining revealed signs of degeneration and regeneration in the quadriceps of both del52hDMD/<i>mdx</i> strains, as evident by variation in fiber size, centralized nuclei and patches of fibrosis and inflammation. Overall pathology appeared to be slightly less extensive in del52hDMD/<i>mdx</i>#37 mice compared to <i>mdx</i>(BL6) and del52hDMD/<i>mdx</i>#35 mice. <b>C</b>) Almost no centralized nuclei were found in wild type mice, while half of the myofibers in <i>mdx</i>(BL6) and del52hDMD/<i>mdx</i>#35 mice had centrally located nuclei. The percentage in del52hDMD/<i>mdx</i>#37 mice was with 26% significantly lower. Data were based on manual counts of 5 randomly taken pictures of 2 males and 2 females per genotype. Asterisks indicate <i>P</i><0.01.