Faculty of Sciences, Engineering and Health, School of Medical and Applied Sciences, Institute for Health and Social Science Research, Central Queensland University, Rockhampton, QLD, Australia.
Eur J Nutr. 2013 Mar;52(2):477-87. doi: 10.1007/s00394-012-0349-x. Epub 2012 Apr 5.
The aim of the study was to examine the acute effects of pre-exercise ingestion of protein, carbohydrate, and a non-caloric placebo on serum concentrations of insulin and cortisol, and the intramuscular gene expression of myostatin- and ubiquitin proteasome pathway (UPP)-related genes following a bout of resistance exercise.
Ten untrained college-aged men participated in three resistance exercise sessions (3 × 10 at 80 % 1RM for bilateral hack squat, leg press, and leg extension) in a cross-over fashion, which were randomly preceded by protein, carbohydrate, or placebo ingestion 30 min prior to training. Pre-supplement/pre-exercise, 2 h and 6 h post-exercise muscle biopsies were obtained during each session and analyzed for mRNA fold changes in myostatin (MSTN), activin IIB, follistatin-like 3 (FSTL3), SMAD specific E3 ubiquitin protein ligase 1 (SMURF1), forkhead box O3, F-box protein 32 (FBXO32), and Muscle RING-finger protein-1, with beta-actin serving as the housekeeping gene. Gene expression of all genes was analyzed using real-time PCR.
Acute feeding appeared to have no significant effect on myostatin or UPP biomarkers. However, resistance exercise resulted in a significant downregulation of MSTN and FBXO32 mRNA expression and a significant upregulation in FSTL3 and SMURF1 mRNA expression (p < 0.05).
An acute bout of resistance exercise results in acute post-exercise alterations in intramuscular mRNA expression of myostatin and UPP markers suggestive of skeletal muscle growth. However, carbohydrate and protein feeding surrounding resistance exercise appear to have little influence on the acute expression of these markers.
本研究旨在探讨运动前摄入蛋白质、碳水化合物和无热量安慰剂对阻力运动后血清胰岛素和皮质醇浓度的急性影响，以及肌肉生长抑制素（MSTN）和泛素蛋白酶体途径（UPP）相关基因的肌肉内基因表达。
10 名未经训练的大学生男子以交叉方式进行 3 次阻力运动（双侧深蹲、腿举和腿屈伸，每组 10 次，强度为 80%1RM），在训练前 30 分钟随机摄入蛋白质、碳水化合物或安慰剂。在每次运动中，在预补充/预运动、运动后 2 小时和 6 小时采集肌肉活检，并分析 MSTN、激活素 IIB、卵泡抑素样 3（FSTL3）、SMAD 特异性 E3 泛素蛋白连接酶 1（SMURF1）、叉头框 O3、F 盒蛋白 32（FBXO32）和肌肉环指蛋白 1 的 mRNA 折叠变化，以肌动蛋白为管家基因。使用实时 PCR 分析所有基因的表达。
急性喂养似乎对 MSTN 或 UPP 生物标志物没有显著影响。然而，阻力运动导致 MSTN 和 FBXO32mRNA 表达显著下调，FSTL3 和 SMURF1mRNA 表达显著上调（p<0.05）。
急性阻力运动导致肌肉内 MSTN 和 UPP 标志物的 mRNA 表达发生急性运动后变化，提示骨骼肌生长。然而，阻力运动前后摄入碳水化合物和蛋白质似乎对这些标志物的急性表达影响不大。
