Dietary fatty acid unsaturation levels, lipoprotein oxidation and circulating chemokine in experimentally induced atherosclerotic rats

Abstract

The dietary balance of long-chain fatty acids may influence processes involving leukocyte endothelial interactions, such as atherogenesis and inflammation. The relationship between proatherogenic lipoproteins and chemotactic motility is still controversial. However, the interaction of the former can increase recruitment of monocytes to the vessel walls and accelerate the events of atherogenesis. The current study examined the effects of unsaturated fatty acid levels on the oxidative susceptibility of lipoprotein, chemokine expressions and their relationship to atherosclerotic lesion development in experimental rats. Male Wistar rats were fed an atherogenic diet for 4 months and the diet was then supplemented with 10% v/w of virgin olive oil (OO group), sunflower oil (SO group) or fish oil (FO group) for 4 and 8 weeks. Blood samples were collected at four time points: at baseline, after feeding with the atherogenic diet and during the dietary regimen (4 and 8 weeks). Plasma lipid profile and lipoprotein oxidative susceptibility (LOS), C-reactive protein (CRP), monocyte chemoattractant protein (MCP-1), and regulated upon activation normal T-cell expressed and secreted (RANTES) were measured. The superoxide dismutase (SOD) and reduced glutathione (GSH) antioxidant activities were also studied in aortic segments. Histological assessment of the aortic segment was determined. Compared to baseline data, the high-fat and cholesterol-enriched diet increased atheroma formation, plasma LOS and inflammatory indexes (CRP, MCP-1, RANTES). However, it dramatically reduced aortic SOD and GSH contents. Dietary treatment of atherosclerotic rats with OO greatly reduced LOS and remarkably increased aortic SOD and GSH contents as compared to the SO- and FO-treated groups. The FO-supplemented diet had a more pronounced lowering effect on MCP-1 and RANTES compared to the OO and SO diets. In conclusion, this study demonstrated a strong relationship between LOS and circulating levels of chemokines. OO is a potent antioxidant and moderate anti-inflammatory, which effectively reduced aortic atherosclerotic lesions more than the SO- or FO-treated groups in male Wistar rats.