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
2013
Feillet Coudray, Christine | Aoun, Manar | Fouret, Gilles | Bonafos, Béatrice | Ramos, Jeanne | Casas, François | Cristol, Jean Paul | Coudray, Charles | Dynamique Musculaire et Métabolisme (DMEM) ; Institut National de la Recherche Agronomique (INRA)-Université de Montpellier (UM) | Nutrition et Alimentation des Populations aux Suds (NutriPass) ; Université Montpellier 1 (UM1)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro) | Université Montpellier 1 (UM1) | Université Montpellier 2 - Sciences et Techniques (UM2) | Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro) | Laboratoire d'Anatomie Pathologique ; Hôpital Gui de Chauliac [CHU Montpellier] ; Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)
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), PPAR gamma co-activator 1 alpha (PGC-1 alpha) 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.
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