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Maintenance of contractile force and increased fatigue resistance in slow‐twitch skeletal muscle of long‐term high‐fat‐fed mice
Author(s) -
Eshima Hiroaki,
Tamura Yoshifumi,
Kakehi Saori,
Kawamori Ryuzo,
Watada Hirotaka
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.1081.2
Subject(s) - skeletal muscle , medicine , muscle fatigue , term (time) , resistance training , endocrinology , cardiology , chemistry , physical medicine and rehabilitation , electromyography , physics , quantum mechanics
High‐fat diet (HFD) has been shown to significantly raise muscle mitochondrial enzyme activity and endurance performance. We recently demonstrated that long‐term HFD impairs contractile force and shift to oxidative fiber composition in fast‐twitch muscle fibers. However, the effects of long‐term HFD on the muscle function (i.e., contractile force and fatigue resistance) of slow‐twitch dominant muscles have not yet been elucidated. Isolated slow‐twitch soleus (SOL) from male C57BL/6J mice was fed a HFD (60% kcal: fat) for 12 weeks. Muscle contractile force were measured under resting conditions and during fatigue induced by repeated tetanus (100 Hz, 50 contraction, 2 s interval). No differences in muscle twitch and tetanic force were evident between HFD and control, whereas fatigue resistance elevated for the entire end‐stage period in HFD (relative force for the initial; CONT, 26.6 ± 1.6 vs HFD, 37.6 ± 1.6%, P < 0.05). SOL muscle weights and cross‐sectional area were unchanged even in HFD compared with the control (P > 0.05). SOL muscles of HFD fed mice showed increased activities of succinate dehydrogenase, and expression of triggers of mitochondrial biogenesis (PGC‐1α and COX IV). Accordingly, mitochondrial fusion index (Mfn2‐to‐Drp1 ratio) was significantly increased in HFD compared to control (+76 ± 4% vs control, P < 0.05). These findings indicate that long‐term HFD induces elevated muscle fatigue resistance in slow‐twitch dominant muscle fiber. The latter may be associated with elevated quantity and/or quality of mitochondria.