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, utilized 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 acid mixtures on linoleic (LA) and alpha-linolenic acid (ALA) metabolism. Cardiomyocytes were divided into groups receiving: (1) control medium; (2) control 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. senescence caused a reduction in the conversion of LA and ALA, and the decrease in their metabolites was bypassed by the different supplementations. The fatty acid composition of cardiomyocyte lipids was therefore affected by both senescence and supplementation, as evidenced by the n-6:n-3 fatty acid ratio 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 groups of cells but one (n-6:n-3, 2:1) an unbalance in the n-6:n-3 fatty acid ratio. 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 ratio.