Skeletal muscle weakness caused by carrageenan-induced inflammation.

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.