Essential fatty acid metabolism in long term primary cultures of rat cardiomyocytes: a beneficial effect of n-6 : n-3 fatty acids supplementation

In long term (21 days) primary cultures of neonatal rat cardiomyocytes, uti lized as a model of in vitro senescence, we investigated the dual effect of the time length in culture and of the supplementation with n-6:n-3.fatty a cid mixtures on linoleic (LA) and cc-linolenic acid (ALA) :metabolism. Card iomyocytes were divided into groups receiving: (1) control medium; (2) cont rol medium plus n-3 fatty acids; (3) and (4) control medium plus n-6 and n- 3 fatty acids in the ratio 1:2 or 2.1, respectively. In control cells, sene scence caused a reduction in the conversion of LA and ALA, and the decrease in their metabolites was bypassed by the different supplementations. The f atty acid composition of cardiomyocyte lipids was therefore affected by bot h senescence and supplementation, as evidenced by the n-6:n-3 fatty acid ra tio and the unsaturation index (U.I.) in cellular lipids. The final result of ageing in culture and of fatty acid supplementations was in all the grou ps of cells but one (n-6:n-3, 2:1) an unbalance in the n-6:n-3 fatty acid r atio. All the supplementations were able to counteract the decrease in the U.I. observed with senescence, but only the n-6:n-3 (2:1) was able to do so by increasing the cellular content of the fatty acids which are precursors of anti-aggregation eicosanoids without altering the n-6:n-3 fatty acid ra tio. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.