DEMONSTRATION OF MITOCHONDRIAL RIBOSOMAL-RNA IN FROZEN AND PARAFFIN-EMBEDDED SECTIONS OF SKELETAL-MUSCLE BY IN-SITU HYBRIDIZATION

We have used in situ hybridization with synthetic oligonucleotide prob es to the 16S sub-unit of mitochondrial ribosomal RNA to detect mitoch ondrial accumulations in biopsies of skeletal muscle from 16 patients with mitochondrial myopathies. In all cases, the distribution of the h ybridization signal matched the pattern of succinate dehydrogenase act ivity in adjacent cryostat sections. In situ hybridization also allowe d Visualization of mitochondrial accumulations in paraffin-embedded se ctions of skeletal muscle that had been fixed in either De Castro's so lution or formalin. DNase pre-treatment did not significantly diminish the intensity of hybridization signal, suggesting that the hybridizat ion is predominantly to RNA. The advantages of this technique are that it allows the investigation of mitochondrial disorders when only para ffin-embedded tissue is available and should also facilitate the demon stration of mitochondrial accumulations in tissues other than skeletal muscle.