Modulatory effects of α- linolenic acid on generation of reactive oxygen species in elaidic acid enriched peritoneal macrophages in rats

Abstract

Fatty acids are known to influence the ability of macrophages to generate reactive oxygen species (ROS). However the effect of elaidic acid (EA, 18:1 trans fatty acid) on ROS generation is not well studied. Rat peritoneal macrophages were enriched with elaidic acid by incubating the cells with 80 µM EA. The macrophages containing EA generated higher amounts of superoxide anion (O₂<b style="mso-bidi-font-weight: normal">^·-)</b>, hydrogen peroxide (H₂O₂) and nitric oxide (NO<b style="mso-bidi-font-weight:normal">^˙</b>) by 54, 123 and 237%, respectively as compared to control cells which did not contain EA. To study the competition of other C18 fatty acids with EA macrophages were incubated with EA along with stearic acid (18:0), oleic acid (18:1), linoleic acid (18:2) and α- linolenic acid (ALA, 18:3). ALA significantly reduced the incorporation of EA into macrophage lipids. This also significantly reduced the generation of O₂<b style="mso-bidi-font-weight: normal">^· ^-</b>, H₂O₂, NO<b style="mso-bidi-font-weight:normal">^˙</b>by macrophages. Studies were also conducted by feeding rats with diet containing partially hydrogenated vegetable fat (PHVF) as a source for EA and linseed oil (LSO) as a source for ALA. The rats were fed AIN-93 diet containing PHVF with 17% EA and incremental amounts of linseed oil for 10 weeks. The peritoneal macrophages from rats fed partially hydrogenated vegetable fat generated higher levels of O₂<b style="mso-bidi-font-weight:normal">^·-</b>, H₂O₂, NO<b style="mso-bidi-font-weight:normal">^˙</b> by 46, 161 and 76% respectively, when compared to rats fed control diets containing ground nut oil. Macrophages from rats fed PHVF with incremental amounts of LSO produced significantly lower levels ROS in a dose dependent manner. Thus ALA reduces the higher levels of ROS generated by macrophages containing EA.