Fig. 5

Study of the expression of nNOS before and after somatic gene transfer of dystrophin or utrophin in the quadriceps of mdx mouse. Transverse serial cryostat sections (10-µm thick) of a quadriceps muscle from mdx mouse stained for HE (upper row), double-immunostained by anti-nNOS antibody (lower row), and by anti-dystrophin antibody (second row, three first columns), or by anti-myc antibody (second row, fourth column). First column: C57BL10 mouse (C57BL10C: C57BL10 control). Second column: mdx mouse aged 42 days. Third column: mdx mouse aged 42 days after injection of adenovirus-mini-dystrophin gene at 5 days postnatal. Fourth column: mdx mouse aged 42 days after injection of adenovirus-utrophin gene at 5 days postnatal. First column: there was a colocalization of dystrophin and nNOS in control mouse. Second column: no dystrophin and no nNOS was detected in mdx mouse. HE demonstrated necrotic fibers (star), and centronucleated fibers. Third column: adenovirus-mediated gene transfer of dystrophin corrected partially the morphological phenotype (less centronucleated muscle fibers, less necrotic fibers, less variation of the size of the fibers). There was no expression of nNOS. Fourth column: adenovirus-mediated gene transfer of utrophin: there were less necrotic and centronucleated muscle fibers and the sizes of the muscle fibers exhibited less variability. No expression of nNOS was demonstrated.