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Updated: Jun 18, 2026
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Immunolabelling Myofiber Degeneration in Muscle Biopsies
Published on: December 5, 2019
Morphological and biochemical patterns in skeletal muscle apoptosis
A D'Emilio1, L Biagiotti, S Burattini
1DISUAN, University of Urbino Carlo Bo, Urbino, Italy.
Histology and Histopathology
|November 20, 2009
Summary
UVB irradiation induces apoptosis in muscle cells, affecting mitochondria and activating caspases. While nucleosomal DNA fragmentation is absent, characteristic ultrastructural changes and double-strand DNA cleavage occur.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Neuromuscular disorders often involve oxidative stress and muscle fiber loss via apoptosis.
- Understanding muscle cell death mechanisms is crucial for treating these conditions.
Purpose of the Study:
- To investigate UVB-induced apoptosis in C2C12 myoblasts and myotubes.
- To analyze the role of mitochondria and caspases in this process.
- To characterize DNA fragmentation patterns during UVB-induced apoptosis.
Main Methods:
- C2C12 myoblasts and myotubes were irradiated with UVB.
- Apoptosis was assessed using scanning and transmission electron microscopy (SEM, TEM), TUNEL assay, and DNA gel electrophoresis.
- Mitochondrial function was evaluated with fluorescent probes (MitoTracker red CMXRos, JC-1).
- Caspase activity and inhibitor effects were analyzed by Western blot and SEM.
Main Results:
- UVB irradiation induced characteristic apoptotic features like membrane blebbing and chromatin condensation in C2C12 cells.
- TUNEL assay showed positivity, indicating DNA damage, but nucleosomal DNA fragmentation was absent.
- Mitochondrial function decreased, and caspase-9 and -3 activation was confirmed.
- Caspase inhibition reduced the number of apoptotic cells.
Conclusions:
- UVB irradiation effectively induces apoptosis in both myoblasts and myotubes, with myotubes showing greater resistance.
- The apoptotic pathway involves mitochondrial dysfunction and caspase activation, but not nucleosomal DNA fragmentation.
- UVB-induced DNA damage manifests as double-strand cleavage and ultrastructural chromatin changes.
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