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Four‐week Ketogenic Diet Improves Aerobic Metabolic Capacity in Extensor Digitrum Longus Muscle of Sedentary Male Rats
Author(s) -
Ogura Yuji,
Yoshihara Toshinori,
Kurosaka Mitsutoshi,
Kakigi Ryo,
Fujiwara Sei-etsu,
Kakehashi Chiaki,
Higashida Kazuhiko,
Funabashi Toshiya
Publication year - 2020
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.2020.34.s1.09047
Subject(s) - ketogenic diet , endocrinology , medicine , ketone bodies , skeletal muscle , ketosis , carbohydrate , ketogenesis , biology , epilepsy , metabolism , diabetes mellitus , psychiatry
Ketogenic diet is an extremely high‐fat diet with low or absence of carbohydrate in the total nutrient. Thus, this diet causes ketone body production from the liver and shifts energy sources from carbohydrate to fat. Whereas previous studies have suggested that ketogenic diet ameliorates brain disorder such as drug‐resistant epilepsy, its influence on peripheral tissue is unclear. Skeletal muscle is an important organ for locomotion and metabolism. Recent studies have suggested that the ketogenic diet changes the energy metabolic properties in the skeletal muscle as well; however, the results are contradictory. Moreover, it remains unknown whether the ketogenic diet affects the muscle contractile function. Therefore, this study aimed to clarify the effect of ketogenic diet on muscle performance and biochemical adaptation in rat skeletal muscle. This study was approved by Institute for Animal Experimentation at St. Marianna University School of Medicine. Male Wistar rats (8 weeks of age) were assigned to either control group (CON) or ketogenic diet group (KD). CON and KD were fed for 4 weeks either control diet (10% fat, 10% protein, 80% carbohydrate) or ketogenic diet (90% fat, 10% protein, 0% carbohydrate), respectively. Body mass was recorded once a week. After the 4‐week feeding period, the animals were anesthetized, and the blood sample was collected to analyze blood ketone concentration. The right extensor digitrum longus (EDL) muscle was used to evaluate the twitch force, tetanic force, and fatigue ex vivo. The left EDL was homogenized and used to analyze the myosin heavy chain composition, the protein expression of metabolic enzymes, and the citrate synthase activity. Body mass was lower in KD than CON at third and fourth week of the feeding period. Blood ketone concentration in KD was significantly higher than CON. There was no statistical difference in the twitch and tetanic forces as well as muscle fatigue between CON and KD. However, the citrate synthase activity in KD was significantly higher than CON. The protein expression of citrate synthase, succinate dehydrogenase, cytochrome c oxidase subunit 4, and 3‐hydroxyacyl‐CoA dehydrogenase in KD was significantly higher than CON. Moreover, there was a shift of myosin heavy chain from type IIb to IIx in KD. Therefore, we conclude that 4‐week ketogenic diet improves skeletal muscle aerobic capacity without obstructing muscle contractile function in the sedentary male rats. Support or Funding Information This work was supported by MEXT/JSPS KAKENHI Grant Numbers JP24650334, JP18K17767.