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Scanning electron microscopic observations on muscle cells of experimental mitochondrial myopathy produced by 2,
H Kawahara1, S Houdou, T Inoué
1Division of Child Neurology, Tottori University School of Medicine, Yonago, Japan.
Abstract:
The morphological changes of the skeletal muscle cells of the rat experimental myopathy induced by 2, 4-dinitrophenol were examined by scanning electron microscopy in comparison with the ultrastructure of normal muscle cells. Specimens were prepared by the Aldehyde-Osmium-DMSO-Osmium method which permits the three-dimensional demonstration of intracellular structures under SEM. In the specimen prepared by the method, myofibrils having been completely dissolved, intracellular membranous structures such as the sarcoplasmic reticulum, T-tubules and mitochondria were clearly demonstrated in three dimensions. In the experimental mitochondrial myopathy, large accumulations of mitochondria were observed at the subsarcolemmal region. Mitochondria in the perinuclear and intermyofibrillar region showed swelling and occasionally accompanied abnormal concentric cristae. The sarcoplasmic reticulum which showed regular network in normal muscle cells entirely disappeared in the mitochondrial myopathy. Although the mitochondrial changes obtained in this study were almost identical to those previously reported by transmission electron microscopy, the changes in the sarcoplasmic reticulum have not been described in previous works.
Insights
Scanning electron microscopy revealed significant mitochondrial and sarcoplasmic reticulum changes in experimental myopathy. This study highlights novel sarcoplasmic reticulum alterations in mitochondrial myopathy.
Area of Science:
- Cell Biology
- Muscle Physiology
- Pathology
Background:
- Skeletal muscle cells undergo morphological changes in myopathies.
- 2,4-dinitrophenol can induce experimental myopathy.
- Scanning electron microscopy (SEM) offers 3D visualization of cellular ultrastructure.
Purpose of the Study:
- To examine the morphological changes in skeletal muscle cells of rats with experimental myopathy induced by 2,4-dinitrophenol.
- To compare these changes with the ultrastructure of normal muscle cells using SEM.
- To elucidate the three-dimensional structure of intracellular components in myopathic muscle.
Main Methods:
- Induction of experimental myopathy in rats using 2,4-dinitrophenol.
- Preparation of muscle specimens using the Aldehyde-Osmium-DMSO-Osmium method for SEM.
- Three-dimensional imaging of intracellular structures, including mitochondria and sarcoplasmic reticulum.
Main Results:
- Large accumulations of mitochondria were observed in the subsarcolemmal region of myopathic muscle cells.
- Mitochondria showed swelling and abnormal concentric cristae in perinuclear and intermyofibrillar regions.
- The sarcoplasmic reticulum network, present in normal cells, was absent in the experimental mitochondrial myopathy.
Conclusions:
- The study provides a detailed 3D ultrastructural analysis of experimental mitochondrial myopathy using SEM.
- Observed mitochondrial changes are consistent with previous transmission electron microscopy findings.
- Significant and previously undescribed alterations in the sarcoplasmic reticulum were identified in this myopathy model.