International Journal of Physical Medicine & Rehabilitation
Open Access

Abstract

Effect of Frequency-Modulated Repetitive Peripheral Magnetic Stimulation (rPMS) on Leg Muscle Atrophy in Animal Model

Yosuke Iwamoto, Naohisa Miyakoshi, Toshiki Matsunaga, Daisuke Kudo, Kimio Saito, Junpei Iida, Yasuhiro Takahashi, Junichi Inoue, Motoki Mita, Shohei Murata, Rena Wakabayashi and Yoichi Shimada 

Objective: To investigate the effect of frequency-modulated repetitive peripheral magnetic stimulation (rPMS) for disuse muscle atrophy in the animal model.
Methods: Thirty-five 6-week-old male SD rats were randomly assigned to 5 groups: the control group (C group), 20-Hz constant-stimulation group (20 Hz group), 5-Hz constant-stimulation group (5 Hz group), 20-Hz/5-Hz modulated-stimulation group (20 Hz/5 Hz group), and non-stimulation group (N group). Atrophy of hind limb muscles was induced by tail suspension for 5 weeks. For the stimulation groups, rPMS to the right sciatic nerve were performed for 30 min a day for 2 weeks. Variables assessed were isometric maximum muscle contraction force and the degree of muscle fatigue of the soleus muscle, muscle weight of tibialis anterior.
Results: The isometric maximum muscle tension was 28.5 ± 3.8 in the 20 Hz group, 20.1 ± 3.8 in the 5 Hz group, 30.6 ± 2.8 in the 20 Hz/5 Hz group, and 21.1 ± 2.3 in the N group. Muscle fatigue in the 20 Hz and the 20 Hz/5 Hz group was significantly lower than in the N group (p <0.05). Muscle weight was 0.56 ± 0.09 in the 20 Hz group, 0.45 ± 0.91 in the 5 Hz group, 0.67 ± 0.79 in the 20 Hz/5 Hz group, and 0.42 ± 0.71 in the N group.
Conclusion: The 20-Hz/5-Hz frequency-modulated rPMS for atrophied leg muscles in the rat tail suspension model improved muscle atrophy equal to or better than 20-Hz constant-frequency stimulation and more than 5-Hz constant-frequency stimulation.