Prevention of experimental autoimmune encephalomyelitis in Lewis rats by a novel fungal source of γ-linolenic acid

Abstract

The effects of oral administration of linoleic- and γ-inolenic-acid-rich oils on the clinical and histopathological manifestations of experimental autoimmune encephalomyelitis (EAE) were investigated in Lewis rats 7 d post-inoculation. γ-Linolenic-acid-rich fungal (Mucor javanicus) oil at 500 mg/kg body weight abrogated clinical and histological signs of EAE although at doses of 200 and 1000 mg/kg body weight it was only effective in delaying the onset of clinical disease. Linoleic-acid-rich safflower-seed (Carthamus tinctorius) oil at 500, 750 and 1000 mg/kg body weight decreased the severity of clinical EAE. disease in a dose-dependent manner. The effects in healthy animals of orally administered γ-linolenic-acid-rich fungal oil (500 mg/kg body weight) and linoleic-acid-rich safflower-seed oil (1000 mg/kg body weight) on splenic lymphocyte proliferative responses to the T-cell mitogen concanavalin-A (Con A), membrane fatty acid composition and lymphocyte sub-sets were also studied. Both treatments enhanced the T-cell proliferative response to Con A. There was no significant effect on the proportion of splenic CD8⁺or CD4⁺lymphocytes. Compositional studies on splenic phosphoglyceride fatty acids of oil-treated animals suggest the above responses were associated with increases in spleen dihomo-γ-linolenic and arachidonic acids.