Influence of dietary linseed oil and sunflower seed oil on some mechanical and metabolic parameters of isolated working rat hearts

Abstract

Summary &horbar; The role played by membrane lipid environment on cardiac function remains poorly defined. The polyunsaturated fatty acid profile of myocardial phospholipids could be of utmost importance in the regulation of key-enzyme activities. This study was undertaken to determine whether selective incorporation of n-6 or n-3 fatty acids in membrane phospholipids might influence cardiac mechanical performances and metabolism. For 8 wk, male weanling Wistar rats were fed a semipurified diet containing either 10% sunflower seed oil (72% C18:2 n-6) or 10% linseed oil (54% C18:3n-3) as the sole source of lipids. The hearts were then removed and perfused according to working mode with a Krebs-Henseleit buffer containing glucose (11 mM) and insulin (10 UII1). Cardiac rate, coronary and aortic flows and ejection fraction were monitored after 30 min of perfusion. Myocardial metabolism was estimated by evaluating the intracellular fate of 1-!4C palmitate. Sunflower seed oil and linseed oil feeding did not modify either coronary or aortic flow, which suggests that cardiac mechanical work was not affected by the diets. Conversely, cardiac rate was significantly decreased (-18%; P < 0.01) when rats were fed the n-3 polyunsaturated fatty acid rich diet. Radioanalysis of the myocardial metabolism suggested that replacing n-6 polyunsaturated fatty acids by n-3 polyunsaturated fatty acids: i) did not alter palmitate uptake; ii) prolonged palmitate incorporation into cardiac triglycerides; iii) reduced beta-oxidation of palmitic acid. These results support the assumption that dietary fatty acids, particularly n-6 and n-3 fatty acids, play an important role in the regulation of cardiac mechanical and metabolic activity.dietary polyunsaturated fatty acid / membrane phospholipid I isolated perfused rat heart I mechanical activity / metabolism

Body adiposity dictates different mechanisms of increased coronary reactivity related to improved in vivo cardiac function

“…The phospholipid fatty acid composition was determined in cardiac homogenates as previously described [24]. The lipids were extracted according to Folch et al .…”

Long-term effect of dietary α-linolenic acid or decosahexaenoic acid on incorporation of decosahexaenoic acid in membranes and its influence on rat heart in vivo

“…Animal experiments have suggested that dietary ALA, with a more efficient conversion process (54), can reduce cardiac arrhythmias in rats, but the reduction is significantly less than that induced by pure DHA or EPA (58). ALA has also been reported to reduce markedly HR in isolated working rat hearts (31). However, the level of synthesis of DHA from its precursor ALA before its incorporation in the heart is a subject of much discussion (10,12,37), depending on mammalian species and target tissues.…”

The effect of a diet fortified with polyunsaturated fatty acids on the level of selected elements in the myocardium of growing pigs

“…Demaison and Grynberg (1991) noticed that administration of fish oil to rats increased the oxidation of palmitic acid and prevented it from accumulating in heart lipids. Mg is an element involved in the oxidation of fatty acids and also influences the integrity of cellular membranes, binding phospholipids (Shils, 1997).…”