Lipid composition and fluidity of the erythrocyte membrane in copper-deficient rats

Abstract

The influence of dietary copper on lipid composition, phospholipid-fatty acid and protein profiles and fluidity of the erythrocyte membranes of rats is reported. In general Cu deficiency in rats induced some changes in the phospholipid-fatty acid profile of erythrocyte membranes when compared with Cu-adequate animals. Stearic (18:0) and docosadienoic (22:2n-3) acids contents, for example, were significantly increased (P< 0.001) while oleic (18:1n-9) and linolenic (18:3n-3) acid contents were significantly depressed (P< 0.001) as a result of Cu deficiency. Moreover the cholesterol:phospholipids molar ratio and the cholesterol (mol):membrane proteins (mg) ratio in Cu-deficient rats were, to different degrees, significantly lower than in animals fed on Cu-adequate diets. In addition, diets deficient in Cu led to a reduction in erythrocyte membrane fluidity (P< 0.001) as assessed by the intramolecular excimer fluorescence of 1,3-di(1-pyrenyI) propane. However, no significant alteration in the phospholipid:protein ratio was observed as a result of differences in dietary treatment. The pattern of erythrocyte membrane proteins obtained with sodium dodecyl sulphate-polyacrylamide gel electro-phoresis did not seem to be influenced by Cu-deficient diets.