Abstract | BACKGROUND: Skeletal muscle atrophy induced by denervation is associated with apoptosis. This study was undertaken to determine the role of apoptosis and the expression of apoptosis-associated genes in rat skeletal muscle made atrophic by brachial plexus injury, and to study the apoptotic signal transduction pathway. METHODS: RESULTS: By terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate end labeling and flow cytometry we found that the percentage of apoptotic muscle cells was higher in atrophic than in healthy skeletal muscle (p < 0.05). DNA laddering could be seen in gel electrophoresis of DNA from atrophic muscle. By electron microscopy, we observed morphologic change of early apoptosis, such as aggregation of chromosomes, expansion of nucleic cistern, and contraction of the nucleus. Using immunohistochemistry, we determined that in atrophic muscle Fas, FADD, and Caspase-8 genes were highly expressed, whereas Bcl-2 was poorly expressed (p < 0.01). However, we did not detect a change in the expression of p53 or c-myc genes. Northern blots indicated that Fas messenger ribonucleic acid was higher and Bcl-2 messenger ribonucleic acid was lower in atrophic than in healthy muscle (p < 0.01). CONCLUSION: There are many more apoptotic cells in muscle atrophied as a result of brachial plexus injury than in healthy muscle, and apoptosis plays an important role in the pathogenesis of atrophy. The apoptotic signal may be transmitted from Fas to FADD to Caspase-8, with a decrease in Bcl-2 expression aggravating the process.
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Authors | H Jin, Z Wu, T Tian, Y Gu |
Journal | The Journal of trauma
(J Trauma)
Vol. 50
Issue 1
Pg. 31-5
(Jan 2001)
ISSN: 0022-5282 [Print] United States |
PMID | 11231666
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Topics |
- Animals
- Apoptosis
- Atrophy
- Brachial Plexus
(injuries)
- Forelimb
- Male
- Models, Animal
- Muscle Denervation
- Muscle, Skeletal
(innervation, pathology)
- Rats
- Rats, Sprague-Dawley
- Signal Transduction
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