Effect of dietary blackcurrant seed oil on mouse macrophage subclasses of choline and ethanolamine glycerophospholipids.

There have been reports that dietary gamma-linolenic acid [18:3(n-6)] and alpha-linolenic acid [18:3(n-3)] are capable of regulating cellular eicosanoid biosynthesis and inflammation. Because the eicosanoid cascade is regulated in part by the distribution of arachidonic acid [20:4(n-6)] among phospholipid subclasses, the effects of feeding blackcurrant seed oil [containing 18:3(n-6) and 18:3(n-3)] on the fatty acid composition of diacyl, alkylacyl and alkenylacyl subclasses of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were studied in mouse peritoneal macrophages. After 4 wk of dietary treatment, the relative distribution (mol %) of macrophage phospholipid classes and subclasses was not altered in animals fed blackcurrant seed oil relative to those fed corn oil [containing linoleic acid, 18:2(n-6)]. Macrophages from blackcurrant seed oil-fed animals had reduced levels of PC diacyl 18:3(n-6), 18:3(n-3), 20:3(n-6), 22:5(n-3), and alkylacyl 20:3(n-6), 22:5(n-3) and 22:6(n-3). In general, dietary blackcurrant treatment produced fatty acid alterations in PE subclasses that were similar to those in PC. A major exception, however, was the reduction in 20:4(n-6) levels in all PE subclasses, whereas no effect in PC subclass 20:4(n-6) levels was noted. These findings indicate i) that pronounced differences in the polyunsaturated fatty acid (PUFA) compositions of macrophage PC and PE subclasses exist following dietary fat manipulation and ii) that 18:3(n-6) and 18:3(n-3) feeding can increase potential anti-flammatory precursor levels of 20:3(n-6) and (n-3) PUFA in the macrophage.