Introduction: The skeletal muscle weakness associated with many chronic diseases has been attributed to the catabolic effect of pro-inflammatory cytokines. We aimed to determine if local muscle inflammation has direct affects on contractile function and contributes to muscle weakness independent of muscle atrophy or mechanical injury.
Methods: Local muscle inflammation was induced by injecting an algal-derived polysaccharide, carrageenan (10 mg/kg), into the right tibialis anterior muscle in healthy ARC mice. The contralateral muscle was injected with sterile isotonic saline, and the muscles were removed after 24 h for measurement of contractile function and cytokine concentration.
Results: Carrageenan significantly reduced maximum specific force, decreased the maximum rate of force development, altered the force-frequency relationship, and increased intramuscular levels of pro-inflammatory cytokines and chemokines.
Conclusions: These results indicate that carrageenan directly affects contractile function and causes skeletal muscle weakness. Local muscle inflammation may contribute to the weakness observed in inflammatory related disorders.
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