engleski

Fatty acid composition of heart lipids in rats fed fat free diet

High concentrations of serum lipids, triacylglycerols and cholesterol associated with low density lipoproteins (LDL), usually accompanied by other risk factors like obesity and smoking, are found to be the main risk factors for the development of coronary heart disease (CHD). Despite modest decrease in CHD mortality during last few decades, CHD remains the major cause of death in the Western world. Fat free diet, used with the aim to reduce fat intake and thus to prevent the development of CHD, turned out to be the cause of hipertriglyceridemia and obesity. Furthermore, when applied for a longer period of time, essential fatty acids and lipid soluble vitamins deficiency is developed. The aim of this study was to analyse possible changes in fatty acid composition of heart lipids in rats fed fat free diet. Animals were fed for two weeks with a fat free diet (FFD) isoenergetic with control diet (CD). Total lipids were extracted from heart homogenate and fatty acid composition was analysed by using gas chromatography. Phospholipids were separated by column and thin layer chromatography and, after a treatment with phospholipase A2, composition of fatty acids linked to sn-1 and sn-2 position of glycerol backbone was analysed. In the fatty acid composition of heart total lipids statistically significant increase in the ratio of palmitoleic (C16:1, n-7) and oleic acid (C18:1, n-9) was found. Stereospecific analysis of fatty acids linked to sn-1 and sn-2 position of phosphatidylcholine revealed no significant changes. In phosphatidylethanolamine and mixed phosphatidylserine + phosphatidylinositol (PS+PI) fraction changes were of the same character, but at different positions. In PE significant decrease of stearic acid and the increase of tetracosenoic acid (C24:1, n-9) was found on sn-1 position, while in PS+PI similar changes were detected on sn-2 position. As expected, short term fat free diet induced some minor changes in the fatty acid composition of heart lipids. The lack of essential fatty acids was compensated by increased endogenous synthesis of monounsaturated fatty acids, especially in the class of total, mostly neutral lipids.

Fatty acid; heart; Rat; Fat free diet

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