Systemic Inflammatory Response Syndrome Increases Immobility-Induced Neuromuscular Weakness

Crit Care Med. 2008 Mar;36(3):910-6. doi: 10.1097/CCM.0B013E3181659669.

Abstract

Objective: Inflammation and immobility are comorbid etiological factors inducing muscle weakness in critically ill patients. This study establishes a rat model to examine the effect of inflammation and immobilization alone and in combination on muscle contraction, histology, and acetylcholine receptor regulation.

Design: Prospective, randomized, experimental study.

Setting: Animal laboratory of a university hospital.

Subjects: Sprague-Dawley rats.

Interventions: To produce systemic inflammation, rats (n = 34) received three consecutive intravenous injections of Corynebacterium parvum on days 0, 4, and 8. Control rats (n = 21) received saline. Both groups were further divided to have one hind limb either immobilized by pinning of knee and ankle joints or sham-immobilized (surgical leg). The contralateral nonsurgical leg of each animal served as control (nonsurgical leg).

Measurements and main results: After 12 days, body weight and muscle mass were significantly reduced in all C. parvum animals compared with saline-injected rats. Immobilization led to local muscle atrophy. Normalized to muscle mass, tetanic contraction was reduced in the surgical leg after immobilization (7.64 +/- 1.91 N/g) and after inflammation (8.71 +/- 2.0 N/g; both p < .05 vs. sham immobilization and saline injection, 11.03 +/- 2.26 N/g). Histology showed an increase in inflammatory cells in all C. parvum-injected animals. Immobilization in combination with C. parvum injection had an additive effect on inflammation. Acetylcholine receptors were increased in immobilized muscles and in all muscles of C. parvum-injected animals.

Conclusions: The muscle weakness in critically ill patients can be replicated in our novel rat model. Inflammation and immobilization independently lead to muscle weakness.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Immobilization / adverse effects*
  • Male
  • Muscle Weakness / etiology*
  • Nervous System Diseases / etiology*
  • Rats
  • Rats, Sprague-Dawley
  • Systemic Inflammatory Response Syndrome / complications*