Park Sookyoung, Hong Yunkyung, Lee Youngjeon, Won Jinyoung, Chang Kyu-Tae, Hong Yonggeun
Cardiovascular & Metabolic Disease Center, College of Biomedical Science & Engineering, Inje University, Gimhae, Korea.
Lab Anim Res. 2012 Mar;28(1):1-9. doi: 10.5625/lar.2012.28.1.1. Epub 2012 Mar 21.
Exercise training can improve strength and lead to adaptations in the skeletal muscle and nervous systems. Skeletal muscles can develop into two types: fast and slow, depending on the expression pattern of myosin heavy chain (MHC) isoforms. Previous studies reported that exercise altered the distribution of muscle fiber types. It is not currently known what changes in the expression of caveolins and types of muscle fiber occur in response to the intensity of exercise. This study determined the changes in expression of caveolins and MHC type after forced exercise in muscular and non-muscular tissues in rats. A control (Con) group to which forced exercise was not applied and an exercise (Ex) group to which forced exercise was applied. Forced exercise, using a treadmill, was introduced at a speed of 25 m/min for 30 min, 3 times/day (07:00, 15:00, 23:00). Homogenized tissues were applied to extract of total RNA for further gene analysis. The expression of caveolin-3 and MHC2a in the gastrocnemius muscle of female rats significantly increased in the Ex group compared with the Con group (P<0.05). Furthermore, in the gastrocnemius muscle of male rats, the expression of MHC2x was significantly different between the two groups (P<0.05). There was an increased expression in caveolin-3 and a slightly decreased expression in TGFβ-1 in muscular tissues implicating caveolin-3 influences the expression of MHC isoforms and TGFβ-1 expression. Eventually, it implicates that caveolin-3 has positive regulatory function in muscle atrophy induced by neural dysfunction with spinal cord injury or stroke.
运动训练可以增强力量，并导致骨骼肌和神经系统发生适应性变化。骨骼肌可根据肌球蛋白重链（MHC）亚型的表达模式发展为两种类型：快肌和慢肌。先前的研究报道，运动可改变肌纤维类型的分布。目前尚不清楚小窝蛋白的表达变化以及肌纤维类型会因运动强度而发生何种改变。本研究确定了大鼠在进行强迫运动后，肌肉组织和非肌肉组织中小窝蛋白的表达变化以及MHC类型的变化。设立未进行强迫运动的对照组（Con组）和进行强迫运动的运动组（Ex组）。使用跑步机以25米/分钟的速度进行强迫运动，每次30分钟，每天3次（07:00、15:00、23:00）。将匀浆后的组织用于提取总RNA以进行进一步的基因分析。与Con组相比，Ex组雌性大鼠腓肠肌中小窝蛋白-3和MHC2a的表达显著增加（P<0.05）。此外，在雄性大鼠的腓肠肌中，两组之间MHC2x的表达存在显著差异（P<0.05）。肌肉组织中小窝蛋白-3的表达增加，而TGFβ-1的表达略有下降，这表明小窝蛋白-3影响MHC亚型的表达和TGFβ-1的表达。最终，这表明小窝蛋白-3在脊髓损伤或中风引起的神经功能障碍所致肌肉萎缩中具有正向调节作用。
