Immunofluorescence survey of mitochondrial content, nuclei and cardiac marker proteins in dystrophic tissue. Confocal microscopy was used for the localization of nuclei, mitochondria and cellular markers in normal ((a), (c), (e), (g), (i), (k), (m), (o), (q), (s)) versus dystrophic MDX ((b), (d), (f), (h), (j), (l), (n), (p), (r), (t)) heart cryosections. Shown is labeling of nuclei with the DNA binding dye DAPI ((a), (b)), visualization of mitochondria with the red-fluorescent MitoTracker dye CMXRos ((e)-(h)), and antibody labeling of full-length dystrophin isoform Dp427 ((c), (d)), desmin DES ((i)-(l)), prohibitin PRO ((m)-(p)) and succinate dehydrogenase SDH ((q)-(t)). The number of nuclei and the labeling of mitochondria with the MitoTracker dye CMXRos were found not to be significantly different between normal and dystrophic preparations. The bars in panels (a) to (t) equal 30 μm.