Effects of neuromuscular electrical stimulation on pulmonary alveola and cytokines in chronic obstructive pulmonary disease (COPD) and skeletal muscle atrophy model mice

[Purpose] It has been reported that exercise affects skeletal muscle in the chronic obstructive pulmonary disease (COPD) disease model. In this study, we examined the effects of neuromuscular electrical stimulation (NMES) in skeletal muscle on alveoli and cytokines. [Materials and Methods] We used twenty wild-type mice, randomly divided into three groups: Group A: Control (non-COPD, non-amyotrophia, non-NMES), Group B: COPD, amyotrophia with NMES and Group C: COPD, amyotrophia without NMES. Among those, a group of mice with ages from 12 to 14 weeks were used to create a chronic obstructive pulmonary disease (COPD) model, a group of mice with ages from 15 to 16 weeks was used to create a disuse syndrome by hind limb suspension, and a group of mice with ages from 17 to 28 weeks (12 weeks) were used to implement NMES. In this study, we used the real-time PCR method to assess the mRNA expression levels. We also conducted morphological analysis, assessed macrophage expression level by staining (general staining and immunostaining), and employed spirometry. [Results] Our study results showed significant decreases in Interleukin-6 (IL-6) levels in the lungs and muscle RING-finger protein-1 (MuRF1) in the muscles. Moreover, the pulmonary stromal macrophage marker (F4/80) and the protease marker (MMP12) showed significantly decreased expression, while no change was observed in the morphological of the alveolar spaces (mean linear intercept). [Conclusion] On the basis of these findings, our study reveals that NMES affects cytokines and macrophages in COPD skeletal muscle atrophy.