Comparison of hydrophobic properties of thoracic lymph chylomicrons from various fats in rats

Chylomicrons are lipoproteins synthesized by the enterocytes from dietary lipids and transferred to circulation via thoracic duct. A chylomicron structure consists of hydrophobic lipid core surrounded by amphipathic lipids and apolipoproteins.Lipoprotein aggregation is caused by hydrophobic nature of lipoproteins which is known to be a cause of atherosclerosis. From this respect, LDL has been extensively studied but not chylomicrons. Recent lines of evidence provide suppport for the atherogenicity of chylomicron remnants which results from interaction of chylomicrons with lipoprotein lipase. Since lipid composition of a lipoprotein is a major determinant of its biophysical properties, chylomicrons from sunflower oil, olive oil, fish oil, margarine, butter and palm oil were obtained from rats through thoracic lymph cannulation, isolated by ultracentrifugation for 5x105 g min at 20 °C and their hydrophobic properties were compared by vorteks induced aggregation and hydrophobic interaction chromatography (HIC).In contrast to LDL, vorteksing did not induce aggregation in chylomicrons. Chylomicrons prepared from sunflower oil and butter exhibited strongest interaction with hydrophobic medium of chromatography, however fish oil chylomicrons showed weaker interaction.Vorteksing of fish oil or butter chylomicrons resulted in more prominent reduction in absorbance compared to chylomicrons from other fats , indicating less micelle stability.Surface hydrophobicity of sunflower chylomicrons appeared noticeably higher compared to chylomicrons from other fats. Ratio of saturated / unsaturated fatty acids of chylomicrons might not be the sole factor determining lipoprotein surface hydrophobicity.Fish oil chylomicrons had less hydrophobicity and low micelle stability. Considering the beneficial effect of fish oil for cardiovascular health, less hydrophobicity together with low micelle stability can provide an additional atherogenicity index for the lipoprotein.