title: Effects of long-term administration of saturated and n-3 fatty acid-rich diets on lipid utilisation and oxidative stress in rat liver and muscle tissues.
abstract: The incidence of metabolic syndrome components including obesity, lipid deregulation, insulin resistance (IR) and non-alcoholic fatty liver disease is increasing rapidly in wealthy societies. The present study was designed to determine the effect of different nutritional lipid patterns (quantity and quality) on lipid utilisation and oxidative stress in the liver and muscle of rats in an integrated fashion. A total of forty-eight Wistar male rats were fed for 12 weeks with a mixed, lard or fish-oil diet, containing either 50 or 300 g lipid/kg. Rats developed liver steatosis associated with moderate liver injury when fed the 30% lipid diets, in spite of the absence of overt obesity or IR, except when fed the lard 30% lipid diet. The intake of the 30% lipid diets decreased hepatic lipogenesis and mitochondriogenesis and increased lipid peroxidation and protein oxidation. Surprisingly, muscle lipid content was not modified whatever the administered diet. The intake of the 30% lipid diets increased the muscle protein expression of fatty acid (FA) translocase/cluster of differentiation 36 (FAT/CD36), PPARg co-activator 1a (PGC-1a) and muscle carnitine palmitoyltransferase 1 (m-CPT1), reflecting increased FA transport in the muscle associated with increased oxidative metabolism. The lard 30% lipid diet led to IR without modifying the muscle lipid content. The fish-oil 30% lipid diet failed to prevent the development of hepatic steatosis and made the tissues more prone to oxidation. Overall, the present study suggests that the FA composition of muscle is more important than lipid accumulation itself in the modulation of insulin sensitivity, and indicates that precaution should be taken when advising an unphysiologically high (pharmacological) supplementation with long-chain n-3 PUFA.
authors: INRA UMR 866, Dynamique Musculaire et Métabolisme, 34060 Montpellier, France.
authors: Christine
authors: C
authors: Feillet-Coudray
authors: Manar
authors: M
authors: Aoun
authors: Gilles
authors: G
authors: Fouret
authors: Béatrice
authors: B
authors: Bonafos
authors: Jeanne
authors: J
authors: Ramos
authors: François
authors: F
authors: Casas
authors: Jean Paul
authors: JP
authors: Cristol
authors: Charles
authors: C
authors: Coudray
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D018955:CD36 Antigens / Q000378:metabolism; D002334:Carnitine O-Palmitoyltransferase / Q000378:metabolism; D004032:Diet; D004041:Dietary Fats / Q000378:metabolism / Q000494:pharmacology; D019587:Dietary Supplements; D005227:Fatty Acids / Q000378:metabolism / Q000494:pharmacology*; D015525:Fatty Acids, Omega-3 / Q000378:metabolism / Q000494:pharmacology*; D005234:Fatty Liver / Q000139:chemically induced / Q000378:metabolism*; D005395:Fish Oils / Q000378:metabolism / Q000494:pharmacology; D007333:Insulin Resistance; D050356:Lipid Metabolism / Q000187:drug effects; D015227:Lipid Peroxidation / Q000187:drug effects; D008099:Liver / Q000378:metabolism*; D008297:Male; D008928:Mitochondria; D009124:Muscle Proteins / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism*; D018384:Oxidative Stress; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D050050:Protein Carbonylation / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D018955:CD36 Antigens; D004041:Dietary Fats; D005227:Fatty Acids; D015525:Fatty Acids, Omega-3; D005395:Fish Oils; D009124:Muscle Proteins; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; C501429:Ppargc1a protein, rat; D014157:Transcription Factors; D002334:Carnitine O-Palmitoyltransferase; C029310:lard