Aoki M S, Lima W P, Miyabara E H, Gouveia C H A, Moriscot A S
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.
Clin Nutr. 2004 Oct;23(5):1176-83. doi: 10.1016/j.clnu.2004.03.004.
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.
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.
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).
Previous creatine supplementation attenuates muscle wasting induced by immobilization. This effect is associated with the increment of intramuscular creatine content.
本研究旨在调查补充肌酸（5克/千克体重/天）对因固定不动而导致的骨骼肌有害适应性变化的影响。
将雄性Wistar大鼠后肢固定，并进行三种饮食干预：对照组、补充肌酸7天（与固定不动同时进行）以及补充肌酸14天（固定不动前7天及与固定不动同时进行）。测定比目鱼肌（SOL）和腓肠肌（GAS）的肌肉重量（湿重/干重）。通过双能X线吸收法（DEXA）分析瘦体重，通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）分析肌球蛋白重链（MHC）分布。
肌酸负荷14天后，固定不动的SOL和GAS的总肌酸含量分别增加了25%和18%。无论饮食干预如何，但固定不动方案导致SOL和GAS重量下降（P<0.001）。然而，补充肌酸14天可使SOL和GAS的质量损失最小化（P<0.05）。我们的研究结果还表明，补充肌酸可使因固定不动而导致的预期的慢肌型向快肌型MHC转变最大化（P<0.05）。
预先补充肌酸可减轻因固定不动而导致的肌肉萎缩。这种作用与肌肉内肌酸含量的增加有关。
