Skeletal Muscle Cell Behavior After Physical Agent Treatments

Area of Science:

• Cell Biology
• Muscle Physiology

Background:

• Apoptosis is crucial for skeletal muscle development and homeostasis.
• Muscle cell death is implicated in myopathies, sarcopenia, denervation, disuse, and strenuous exercise.

Purpose of the Study:

• To investigate skeletal muscle cell death induced by various physical agents in vitro.
• To analyze the morpho-functional and molecular responses of C2C12 myoblasts and myotubes to UVB, hyperthermia, low pH, and hypothermia.

Main Methods:

• C2C12 myoblasts and myotubes were exposed to UVB, hyperthermia (43°C), low pH, and hypothermia (0-6°C).
• Morphological, in situ DNA fragmentation, and molecular analyses (caspase pathway, autophagy) were performed after recovery periods.
• Cellular responses were assessed using morpho-functional and molecular approaches.

Main Results:

• UVB, hyperthermia, and low pH induced apoptosis and DNA fragmentation, with caspase involvement.
• Low pH also caused necrosis with swollen nuclei; apoptotic and necrotic nuclei were observed in the same myotube.
• Hypothermia induced minimal chromatin changes and increased autophagy, without DNA fragmentation or caspase activation.

Conclusions:

• Skeletal muscle cells are sensitive to physical agents, with UVB, hyperthermia, and acidosis inducing apoptotic cell death.
• Hypothermia promotes an autophagic response, suggesting a role in delaying muscle inflammation and injury.
• Understanding these responses provides insights into muscle cell death mechanisms and potential therapeutic strategies.