A DIGE approach for the assessment of rat soleus muscle changes during unloading: effect of acetyl-L-carnitine supplementation

Proteomics. 2008 Sep;8(17):3588-604. doi: 10.1002/pmic.200701176.


After hind limb suspension, a remodeling of postural muscle phenotype is observed. This remodeling results in a shift of muscle profile from slow-oxidative to fast-glycolytic. These metabolic changes and fiber type shift increase muscle fatigability. Acetyl-L-carnitine (ALCAR) influences the skeletal muscle phenotype of soleus muscle suggesting a positive role of dietary supplementation of ALCAR during unloading. In the present study, we applied a 2-D DIGE, mass spectrometry and biochemical assays, to assess qualitative and quantitative differences in the proteome of rat slow-twitch soleus muscle subjected to disuse. Meanwhile, the effects of ALCAR administration on muscle proteomic profile in both unloading and normal-loading conditions were evaluated. The results indicate a modulation of troponin I and tropomyosin complex to regulate fiber type transition. Associated, or induced, metabolic changes with an increment of glycolytic enzymes and a decreased capacity of fat oxidation are observed. These metabolic changes appear to be counteracted by ALCAR treatment, which restores the mitochondrial mass and decreases the glycolytic enzyme expression, suggesting a normalization of the metabolic shift observed in unloaded animals. This normalization is accompanied by a maintenance of body weight and seems to prevent a switch of fiber type.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylcarnitine / pharmacology*
  • Animals
  • Electrophoresis, Gel, Two-Dimensional
  • Hindlimb Suspension / physiology*
  • Male
  • Mitochondria, Muscle / drug effects
  • Muscle Proteins / drug effects*
  • Muscle, Skeletal / drug effects
  • Muscle, Skeletal / physiology*
  • Myosin Heavy Chains / metabolism
  • Rats
  • Rats, Wistar
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization


  • Muscle Proteins
  • Acetylcarnitine
  • Myosin Heavy Chains