title: Deleteriuos effects of immobilization upon rat skeletal muscle: role of creatine supplementation.
abstract: OBJECTIVE
  The aim of the study was to investigate the impact of creatine feeding (5 g kg(-1) body weight day(-1)) upon the deleterious adaptations in skeletal muscle induced by immobilization.
  
  
  METHODS
  Male Wistar rats were submitted to hind limb immobilization together with three dietary manipulations: control, supplemented with creatine for 7 days (along with immobilization) and supplemented with creatine for 14 days (7 days before immobilization and together with immobilization). Muscle weight (wet/dry) was determined in the soleus (SOL) and gastrocnemius (GAS). The analysis of lean mass was performed by DEXA and myosin heavy chain (MHC) distribution by SDS-PAGE.
  
  
  RESULTS
  After 14 days of creatine loading, immobilized SOL and GAS total creatine content were increased by 25% and 18%, respectively. Regardless of dietary manipulation, the immobilization protocol induced a decrease in the weight of SOL and GAS (P < 0.001). However, creatine feeding for 14 days minimized mass loss in the SOL and GAS (P < 0.05). Our findings also indicate that creatine supplementation maximizes the expected slow-to-fast MHC shift driven by immobilization (P < 0.05).
  
  
  CONCLUSIONS
  Previous creatine supplementation attenuates muscle wasting induced by immobilization. This effect is associated with the increment of intramuscular creatine content.
authors.affiliation: Laboratory of Molecular Biology of Muscle Plasticity, Department of Histology and Embryology, Institute of Biomedical science, USP, Marcelo Saldanha Aoki, Av. Lineu Prestes, 1524., CEP 05508-900 São Paulo, SP, Brazil. msaoki@usp.br
authors.forename: M S
authors.initials: MS
authors.lastname: Aoki
authors.forename: W P
authors.initials: WP
authors.lastname: Lima
authors.forename: E H
authors.initials: EH
authors.lastname: Miyabara
authors.forename: C H A
authors.initials: CH
authors.lastname: Gouveia
authors.forename: A S
authors.initials: AS
authors.lastname: Moriscot
mesh_terms: D000284:Administration, Oral; D000818:Animals; D003401:Creatine / Q000008:administration & dosage* / Q000378:metabolism*; D019417:Hindlimb Suspension; D008297:Male; D018656:Muscle Fibers, Fast-Twitch / Q000378:metabolism; D018657:Muscle Fibers, Slow-Twitch / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000473:pathology; D009133:Muscular Atrophy / Q000378:metabolism / Q000517:prevention & control*; D018995:Myosin Heavy Chains / Q000378:metabolism*; D009929:Organ Size; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar
chemical_list: D018995:Myosin Heavy Chains; D003401:Creatine