Jeneson J A L, de Snoo M W, Verlinden N A T, Joosten B J L J, Doornenbal A, Schot A, Everts M E
Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
Acta Physiol (Oxf). 2007 Jun;190(2):151-61. doi: 10.1111/j.1748-1716.2007.01680.x. Epub 2007 Mar 30.
The present study is the first to compare the physiological impact of either forced treadmill or voluntary wheel running exercise on hindlimb muscle in mice.
Male C57BL/6 mice were subjected to either 6 weeks of forced treadmill or voluntary wheel running exercise. Mice in the treadmill running exercise group (TRE; n = 8) ran 1.9 km day(-1) at a speed of 16 m min(-1) against an uphill incline of 11 degrees. In the running wheel exercise group (RWE; n = 8) animals ran 8.8 +/- 0.2 km per day (average speed 42 +/- 2 m min(-1)). After the experimental period, animals were killed and mechanical performance and oxygen consumption of isolated extensor digitorum longus (EDL) muscle were determined during serial electrical stimulation at 0.5, 1 and 2 Hz.
Steady-state half-width time (HWT) of twitch contraction at 0.5 Hz was significantly shorter in TRE and RWE than controls (CON) (41.3 +/- 0.2, 41.3 +/- 0.1 and 44.3 +/- 0.1 s respectively; P < 0.05). The rate of fatigue development and HWT lengthening at 2 Hz was the same in RWE and CON but lower in TRE (1.2-fold and twofold respectively; P < 0.05). EDL oxygen consumption, mitochondrial content and myosin heavy chain (MyHC) composition were not different between the groups.
These results indicate that both exercise modalities have an effect on a hindlimb fast-twitch muscle in mice, with the greatest impact seen with forced treadmill running.
本研究首次比较强迫跑步机运动或自主轮转运动对小鼠后肢肌肉的生理影响。
雄性C57BL/6小鼠进行为期6周的强迫跑步机运动或自主轮转运动。跑步机运动组（TRE；n = 8）的小鼠以16米/分钟的速度、11度的上坡坡度每天跑1.9千米。在轮转运动组（RWE；n = 8）中，动物每天跑8.8±0.2千米（平均速度42±2米/分钟）。实验期结束后，处死动物，并在0.5、1和2赫兹的系列电刺激过程中测定离体趾长伸肌（EDL）的机械性能和耗氧量。
在0.5赫兹时，TRE组和RWE组的单收缩稳态半峰宽时间（HWT）显著短于对照组（CON）（分别为41.3±0.2、41.3±0.1和44.3±0.1秒；P < 0.05）。在2赫兹时，RWE组和CON组的疲劳发展速率和HWT延长情况相同，但TRE组较低（分别为1.2倍和2倍；P < 0.05）。各组之间EDL的耗氧量、线粒体含量和肌球蛋白重链（MyHC）组成没有差异。
这些结果表明，两种运动方式均对小鼠后肢快肌有影响，其中强迫跑步机运动的影响最大。
