Macrophage and Vitamin E

Abstract

To clarify the role of vitamin E in the modulation of macrophages, we investigated its effect on O_2^- and PGE_2 production in macrophages. Macrophases isolated from vitamin E-treated rats, and containing an extremely high level of α-tocophrol, showed lower O_2^- and PGE_2 production following stimulation with PMA or calcium ionophore A23187 compared to those of control macrophages. We also investigated the mechanism by which vitamin E inhibits both O_2^- and PGE_2 production in macrophages, by measuring the activities of protein kinase C and phospholipase A_2 in intact macrophages and cell-free homogenate system. Vitamin E did not directly inhibit phospholipase A_2 activity but inhibited phospholipase A_2 activation through phosphorylation and translocation of the enzyme itself in the intracellular signal transduction. From these results, it was concluded that the action of vitamin E was due to indirect inhibition of NADPH oxidase and phospholipase A_2 activities through the signal transduction system such as protein kinase C and intracellular Ca^<2+>.