Biglari Soheil, Afousi Alireza Ghardashi, Mafi Farnoosh, Shabkhiz Fatemeh
Department of Exercise Physiology, Faculty of Physical Education and Exercise Sciences, University of Tehran, Tehran, Islamic Republic of Iran.
Physiol Int. 2020 Jul 7;107(2):220-230. doi: 10.1556/2060.2020.00020.
It has been shown that high-intensity interval training (HIIT) leads to skeletal muscle hypertrophy; however, its mechanisms of cellular and molecular regulation are still unclear. The purpose of this study was to investigate the effect of HIIT on muscle hypertrophy and major signal transduction pathways.
12 male rats were randomly divided into two groups: control and HIIT. The exercise group performed 30-min HIIT in each session (5 × 4-min intervals running at 85-95% VO2max separated by 2-min active rest at 55-60% VO2max), 3 days/week for 8 weeks. Muscle fiber cross-sectional area (CSA) and the expression of signal transduction pathway proteins were determined in the gastrocnemius muscle.
In the HIIT group, the expression of IGF-I, IGF-IR Akt, p-Akt, AMPKα, p-AMPKα and follistatin increased significantly, whereas a significant decrease was observed in the expression of FoxO1, p-FoxO1, myostatin, ActRIIB, Smad2/3 and p-Smad2/3 (P < 0.05). However, there were no significant differences between the HIIT and control groups in the expression of mTOR, p-mTOR, P70S6K, and p-P70S6K (P > 0.05). In addition, CSA and gastrocnemius muscle weight increased significantly in the HIIT group (P < 0.05).
HIIT induced muscle hypertrophy by improving IGF-I/Akt/FoxO and myostatin/Smad signal transduction pathways.
已表明高强度间歇训练（HIIT）可导致骨骼肌肥大；然而，其细胞和分子调节机制仍不清楚。本研究的目的是探讨HIIT对肌肉肥大及主要信号转导通路的影响。
将12只雄性大鼠随机分为两组：对照组和HIIT组。运动组每次进行30分钟的HIIT（5个4分钟的间歇，以85 - 95%的最大摄氧量奔跑，中间间隔2分钟以55 - 60%的最大摄氧量进行主动休息），每周3天，共8周。测定腓肠肌的肌纤维横截面积（CSA）和信号转导通路蛋白的表达。
在HIIT组中，IGF - I、IGF - IR、Akt、p - Akt、AMPKα、p - AMPKα和卵泡抑素的表达显著增加，而FoxO1、p - FoxO1、肌肉生长抑制素、ActRIIB、Smad2/3和p - Smad2/3的表达显著降低（P < 0.05）。然而，HIIT组和对照组在mTOR、p - mTOR、P70S6K和p - P70S6K的表达上无显著差异（P > 0.05）。此外，HIIT组的CSA和腓肠肌重量显著增加（P < 0.05）。
HIIT通过改善IGF - I/Akt/FoxO和肌肉生长抑制素/Smad信号转导通路诱导肌肉肥大。
