title: Effects of different fatty acid chain lengths on fatty acid oxidation-related protein expression levels in rat skeletal muscles.
abstract: Skeletal muscles can adapt to dietary interventions that affect energy metabolism. Dietary intake of medium-chain fatty acids (MCFAs) enhances mitochondrial oxidation of fatty acids (FAO) in type IIa skeletal muscle fibers. However, the effect of MCFAs diet on mitochondrial or cytoplasmic FAO-related protein expression levels in different types of muscle fibers remains unclear. This study aims to examine the effects of a high-fat diet, containing MCFAs, on mitochondrial enzyme activities and heart-type fatty acid-binding protein (H-FABP) levels in different types of skeletal muscle fibers. Five-week-old male Wistar rats were assigned to one of the following three dietary conditions: standard chow (SC, 12% of calories from fat), high-fat MCFA, or high-fat long-chain fatty acids (LCFAs) diet (60% of calories from fat for both). The animals were provided food and water ad libitum for 4 weeks, following which citrate synthase (CS) activity and H-FABP concentration were analyzed. The epididymal fat pads (EFP) were significantly smaller in the MCFA group than in the LCFA group (p < 0.05). MCFA-fed group displayed an increase in CS activity compared with that observed in SC-fed controls in all types of skeletal muscle fibers (triceps, surface portion of gastrocnemius (gasS), deep portion of gastrocnemius (gasD), and soleus; p < 0.05,). H-FABP concentration was significantly higher in the LCFA group than in both the SC-fed and MCFA-fed groups (triceps, gasS, gasD, and soleus; p < 0.05,). However, no significant difference was observed in the H-FABP concentrations between the SC-fed and MCFA-fed groups. The results of this study showed that the MCFA diet can increase the expression of the mitochondrial enzyme CS, but not that of H-FABP, in both fast- and slow-twitch muscle fibers, suggesting that H-FABP expression is dependent on the chain length of fatty acids in the cytoplasm of skeletal muscles cells.
authors.affiliation: Graduate School of Natural Sciences and Technology, Kanazawa University, Kanazawa, 920-1192, Japan; Department of Exercise Physiology, Nara University of Education, Nara, 630-8528, Japan.
authors.forename: Rie
authors.initials: R
authors.lastname: Ishizawa
authors.forename: Kazumi
authors.initials: K
authors.lastname: Masuda
authors.forename: Susumu
authors.initials: S
authors.lastname: Sakata
authors.forename: Akira
authors.initials: A
authors.lastname: Nakatani
mesh_terms: D000818:Animals; D002950:Citrate (si)-Synthase / Q000378:metabolism; D059305:Diet, High-Fat / Q000009:adverse effects*; D000074026:Fatty Acid Binding Protein 3; D050556:Fatty Acid-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D005227:Fatty Acids / Q000008:administration & dosage / Q000737:chemistry* / Q000378:metabolism*; D015870:Gene Expression; D008297:Male; D008931:Mitochondria, Muscle / Q000201:enzymology / Q000378:metabolism; D009124:Muscle Proteins / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D010084:Oxidation-Reduction; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
chemical_list: C509948:FABP3 protein, rat; D000074026:Fatty Acid Binding Protein 3; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids; D009124:Muscle Proteins; D012333:RNA, Messenger; D002950:Citrate (si)-Synthase