Effect of NMES training program on muscle inflammatory signaling, cross sectional area, and fiber type

Research Objectives: To quantify the effects of a novel combination neuromuscular electrical stimulation (Comb-NMES) training program on skeletal muscle inflammatory signaling and fiber distribution and cross-sectional area in individuals with acute spinal cord injury.

Design: Randomized controlled clinical trial.

Setting: In-patient rehabilitation setting.

Participants: 15 participants (30.47±8.8 y/o), with traumatic SCI (C6-L1 and AIS A, B), within 14 days of the SCI participated in the study.

Interventions: The intervention group received a Comb-NMES training program that combines dynamic contractions (resistance training) via high-frequency electrical stimulation with twitch contractions (aerobic training) via low-frequency electrical stimulation on the quadriceps muscle group on both legs. The control group received a sham treatment, including passive dynamic exercise of the lower legs and transcutaneous electrical nerve stimulation (TENS). Interventions were given 3 times/week for 3-5 weeks. Muscle samples were collected from the Vastus Lateralis muscle within 14 days of SCI and before discharge.

Main Outcome Measures: Immunoblotting was performed to quantify muscle inflammatory signaling proteins (Jak1, Stat3, Traf6, NF-kBp65, p-NF-kB p65, TLR4, TNF-R1, MuRF1, Atrogin, MyoD1, IL6, IL-1 RA, Tweak, TweakR, IL-6R, IL-1B, NF-Kappa-B1 p105). The relative cross-sectional area and distributions of myofiber types I, IIa, and IIax/IIx were determined immunohistochemically.

Results: Protein expression for Jak1, Stat3, and IL-6 and the distribution of Type I and IIa fibers increased, and the distribution of Type IIx fibers decreased in the Comb-NMES group.
In addition, muscle fiber cross-sectional area was decreased in both groups; however, the reduction was greater in the control group.

Conclusions: This preliminary data suggests that Comb-NMES training may help maintain a healthy distribution of muscle fiber types and slow down atrophy by upregulating IL-6/JAK/STAT pathway for muscle growth and regeneration in the acute stages of SCI.

Author(s) Disclosures: no conflict of interest