Comparative Effects Of Two Exercise Modalities On Mots-c Levels In Rats

Abstract

The mitochondrial-derived peptide MOTS-c is an important cyto-protector in helping maintain mitochondrial function and cellular viability, and regulating metabolic homeostasis. It is important to understand the effects of different exercise modalities on MOTS-c levels in various physiological systems in order to identify its role as a signal of physical exercise. PURPOSE: To explore the comparative effects of moderate-intensity aerobic exercise and resistance exercise on levels of MOTS-c in the serum, skeletal muscle and heart. METHODS: Thirty male Sprague-Dawley (SD) rats were randomly divided into three groups: a control group (C, n = 10), an aerobic exercise group (A, n = 10) and a resistance exercise group (R, n = 10). Rats in the A group ran on a treadmill at 21 m/min for 60 min per day, 5 days per week, while rats in the R group climbed a ladder with incremental loads (50%, 75%, 90% and 100% 1RM respectively, 3 times/level, 5 days per week). The training period lasted for 4 weeks. Resting MOTS-c levels in the serum, skeletal muscle, and myocardium were evaluated by enzyme-linked immunosorbent assays, and group differences in MOTS-c levels were determined by using one-way ANOVAs with post-hoc tests. RESULTS: Serum MOTS-c levels were significantly higher in A and R rats compared to C rats (both p < 0.01). No difference in serum MOTS-c levels was found between A and R rats. A significant effect of interaction between fiber type and exercise modality was found on skeletal muscle MOTS-c levels. MOTS-c levels in soleus were significantly higher in A rats compared to C and R rats (p < 0.01 and p < 0.05, respectively), while MOTS-c levels in gastrocnemius were significantly higher in R rats compared to C and A rats (both p < 0.05). Myocardial MOTS-c levels were significantly higher in A rats compared to C rats (p < 0.01), while no difference was found between R and C rats. CONCLUSION: Both exercise modalities increased MOTS-c levels in the serum, and induced MOTS-c uptake into the skeletal muscle. Aerobic exercise may be more effective in facilitating MOTS-c uptake into slow twitch muscle fibers and myocardium. Further research is warranted to clarify the underlying mechanisms. (This study was funded by National Natural Science Foundation of China: Grant Number 31971104)