Exercise modality-dependent mitochondrial respiratory capacity in satellite cells and conditioned serum-induced responses in cultured myotubes

Sep 28, 2026

Exercise-induced mitochondrial adaptations underpin muscle performance and metabolic well-being. This study examined whether moderate-intensity swimming (MOD) or high-intensity interval training (HIIT) relates to mitochondrial function in skeletal muscle cells exposed to exercise-conditioned serum. Male ICR mice were assigned to Sedentary, MOD, or HIIT. MOD increased satellite-cell respiration, ATP production, and maximal capacity versus Sedentary and HIIT. HIIT serum acutely enhanced maximal respiration in C2C12 myotubes; chronic serum improved parameters without modality specificity.

LanguageEnglish

CategoryHealthcare

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Reading Time35 min

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Introduction

Exercise modalities and mitochondrial mechanisms

Exerkines and systemic regulation

DOI: 10.1113/EP092922 RESEARCH ARTICLE Exercise modality-dependent mitochondrial respiratory capacity in satellite cells and conditioned serum-induced responses in cultured myotubes Takanaga Shirai1, 2 Hayato Shinkai3 Shunsuke Sugiyama3 Kohei Takeda5 Riku Tanimura2, 3 Kazuki Uemichi2,4 Yu Kitaoka1 Tohru Takemasa6 1 Department of Human Sciences, Kanagawa University, Kanagawa, Japan 2Japan Society for Promotion Science, Chiyoda-ku, Tokyo, Japan 3 Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan 4 Research Organization of Science and Technology, Ritsumeikan University, Shiga, Japan 5School of Political Science and Economic, Meiji University, Tokyo, Japan 6 Institute of Health and Sport Sciences, University of Tsukuba, Ibaraki, Japan Correspondence Tohru Takemasa, Institute of Health and Sport Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8574, Japan. [Email:](Email: takemasa.tohru.gm@u.tsukuba.ac.jp)[ takemasa.tohru.gm@u.tsukuba.ac.jp](Email: takemasa.tohru.gm@u.tsukuba.ac.jp) Funding information Japan Society for the Promotion of Science, Grant/Award Numbers: 20J15222, 22K17692, 23KJ2060, 23KJ0237, 23H03266; Nakatomi Foundation Handling Editor: Damian Bailey Abstract Exercise-induced mitochondrial adaptations contribute to muscle function and metabolic health. We aimed to investigate the association of moderate-intensity swimming (MOD) and high-intensity interval training (HIIT) with mitochondrial function in skeletal muscle cells treated with exercise-conditioned serum. Male ICR mice (7–8 weeks old) were assigned to the Sedentary, MOD or HIIT group. The MOD group underwent five sessions of 60 min. The HIIT group performed weighted high-intensity swimming intervals. This study assessed mitochondrial enzyme activity in the plantaris muscle, mitochondrial respiratory capacity in isolated satellite cells, and mitochondrial function in C2C12 myotubes treated with exercise-derived serum. Serum was obtained immediately and 24 h postexercise to assess acute effects and chronic adaptations, respectively. The MOD and HIIT groups demonstrated significantly increased muscle citrate synthase and cytochrome c oxidase activities compared with the Sedentary group, but with no significant differences between the MOD and HIIT groups. Satellite cells exhibited higher basal respiration, ATP production and maximal respiratory capacity in the MOD group than in the Sedentary and HIIT groups. Acute serum notably improved maximal mitochondrial respiration in cultured C2C12 myotubes in the HIIT group, whereas serum from chronic training improved those parameters but demonstrated no modality-specific effects. MOD enhances mitochondrial respiratory function in satellite cells, probably owing to sustained aerobic metabolic signalling, whereas HIIT produces a potent but transient systemic response that acutely boosts mitochondrial function in muscle cells. The differential effects of exercise modalities emphasize the importance of timing and exercise modality in driving specific mitochondrial adaptations, thereby providing valuable insights for tailored exercise prescriptions for optimizing metabolic health. KEYWORDS exercise conditioned serum, exercise modality, mitochondrial respiration, satellite cell, skeletal muscle This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2025 The Author(s). Experimental Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society. SHIRAI ET AL. 227 1 INTRODUCTION Exercise is a fundamental driver of health and athletic performance, but the biological mechanisms that underlie the effects of different types of exercise on the body remain an active area of research. The mitochondria, the energy centres of our cells, are important

FAQs

What exercise modalities were compared in the study?

The study compared moderate-intensity swimming (MOD) with high-intensity interval training (HIIT) against a Sedentary group.

How were serum samples used to assess mitochondrial responses?

Serum was collected immediately after exercise to evaluate acute effects and 24 hours later to assess chronic adaptations, then applied to cells including C2C12 myotubes.

Did MOD and HIIT produce different mitochondrial effects across experimental settings?

MOD enhanced mitochondrial respiratory function in satellite cells with modality-specific effects, while HIIT produced a strong but largely transient systemic response that acutely boosted mitochondrial function in muscle cells without clear modality-specific effects after chronic training.

Sep 28, 2026

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