EFFECTS OF CONJUGATED LINOLEIC ACID ISOMERS ON SERUM TUMOR NECROSIS FACTOR-A CONCENTRATION IN MICE

In previously studies, we showed that tumor necrosis factor-α (TNF-a), a cytokine involved in a variety of biologically important events, is partially involved in the effects of conjugated linoleic acid (CLA). In this report, we further tested the effects of individual CLA isomers on serum TNF-a concentration along with other biological markers in mice. The animals were fed experimental diets (control, 0.5% CLA-mixed isomer, 0.25% cis-9, trans-11 CLA or 0.25% trans-10, cis-12 CLA) for 5 days and were then challenged with endotoxin. Both cis-9, trans-11 and trans-10, cis-12 CLA isomers reduced serum TNF-a levels compared to control. CLA had no effect on the other biological markers examined. These results suggest possible early involvement of CLA in immune and/or inflammatory responses, followed by reduction of body fat. Its effect on TNF-a helps explain in part how CLA modulates other biological functions such as immune response, insulin responses, atherosclerosis and cancer.