No abstract

The fatty acid profile of hepatocytes and adipocytes is determined by the composition of the dietary lipids. It remains unclear which fatty acid components contribute to the development or reduction of insulin resistance. The present work examined the fatty acid composition of both tissues in sucrose-induced obese rats receiving fish oil to determine whether the effect of dietary (n-3) polyunsaturated fatty acids (PUFAs) on the reversion of metabolic syndrome in these rats is associated to changes in the fatty acid composition of hepatocyte and adipocyte membrane lipids. Animals with metabolic syndrome were divided into a corn-canola oil diet group and a fish oil diet group, and tissues fatty acids composition were analyzed after 6 weeks of dietary treatment. Fatty acid profiles of the total membrane lipids were modified by the fatty acid composition of the diets fed to rats. N-3 PUFAs levels in animals receiving the fish oil diet plus sucrose in drinking water were significantly higher than in animals under corn-canola oil diets. It is concluded that in sucrose-induced obese rats, consumption of dietary fish oil had beneficial effects on the metabolic syndrome and that such effects would be conditioned by the changes in the n-3 PUFAs composition in hepatic and adipose tissues because they alter membrane properties and modify the type of substrates available for the production of active lipid metabolites acting on insulin resistance and obesity.

Oxysterols are structurally similar to cholesterol, but are characterized by one or more additional oxygen-containing functional groups. These compounds are implicated in inflammation given their ability to cause irreversible damage to vascular cells. The aim of this study was to study the alteration of some inflammatory biomarkers in Wistar rats in response to dietary oxysterols. Eighteen rats were randomly divided into three groups of six rats each. A standard diet supplemented with 1% (w/w) pure cholesterol (Chol group) or 1% (w/w) of an oxidized cholesterol mixture (COPs group) was fed for 8 weeks. Blood serum was separated; abdominal, pericardial, and epididymal adipose tissue was removed carefully. The COPs subjects exhibited significant increase in blood pressure and serum triacylgycerols as well as increased body fat index and pericardic, abdominal, and epididymal adipose tissue. These effects were accompanied by elevated circulating levels of plasma high-sensitivity C-reactive protein, tumor necrosis factor alpha, and resistin. We suggest that dietary oxysterols have an important pro-inflammatory effect.

RESUMENUna dieta enriquecida con CLA mejora el daño a órganos asociados al síndrome metabólico en ratas hipertensas espontáneas.El objetivo del presente estudio fue proporcionar evidencia que el CLA dietario puede evitar la patogénesis del sín-drome metabólico en la estructura tisular, lo que sugiere beneficios potenciales en el desarrollo de este síndrome. Dos grupos de ratas Wistar macho espontáneamente hipertensas (SHR) fueron alimentadas con una dieta normal por 8 semanas: una dieta contenía 7.5% de aceite de girasol (grupo VS-HR), y el otro contenía 6% de aceite de girasol y 1.5% de CLA (grupo CLA-SHR). A un grupo testigo sano de ratas macho Kyoto-Wistar les fue proporcionada una dieta normal con 7.5% de aceite de girasol. Los animales fueron sacrificados y se tomaron secciones de hígado, riñones y aorta, las cuales fueron fijadas en formaldehído al 10% y teñidas con Hematoxilina y Eosina. Las tinciones de aorta mostraron morfología irregular del endotelio en la aorta solo en el grupo V-SHR; el parénquima hepático se caracterizó por infiltración de neutrófilos inflamatorios, fibrosis y engrosamiento del epitelio de la vena porta, hiperplasia hepática y esteatosis. El tejido renal de este mismo grupo evidenció hiperplasia en las células del endotelio de la cápsula de Bowman. No se observaron cambios anormales histológicos tanto en el grupo testigo como en el alimentado con CLA, lo que sugiere un papel protector del CLA en el desarrollo del síndrome metabólico. PALABRAS CLAVE: Ácido linoléico conjugado -Disfunción endotelial -Esteatosis -Síndrome metabólico -Resistencia a la insulina. SUMMARYA CLA enriched diet improves organ damage associated with the metabolic syndrome in spontaneous hypertensive rats.The purpose of this study was to provide evidence that dietary CLA can prevent the pathogenesis of metabolic syndrome in tissue structure, suggesting potential benefits in the onset of this syndrome. Wistar male spontaneous hypertensive rats (SHR), were classified into two groups that were fed a standard diet for eight weeks: one with 7.5% sunflower oil (V-SHR group), and the other with 6% sunflower oil and 1.5% CLA (CLA-SHR group). A control healthy group consisted of Kyoto-Wistar male rats fed the standard diet with 7.5% sunflower oil. The animals were sacrificed, and sections A CLA enriched diet improves organ damage associated with the metabolic syndrome in spontaneous hypertensive rats of liver, kidneys and aorta were fixed in 10% formaldehyde, and then stained with Hematoxylin and Eosin. Only in the V-SHR group, the stain of the aorta indicated irregular endothelial morphology; liver parenchyma was characterized by an infiltration of inflammatory neutrophils, fibrosis, thickening of the portal vein epithelium, hepatocyte hyperplasia and steatosis. The renal tissue of this group evidenced hyperplasia in the cells of the endothelial of Bowman´s capsule. Abnormal histological changes were not observed in either the control group or the rats fed with CLA, suggesting a protective role of CLA in the onset of m...