Dietary effect of pomegranate seed oil on immune function and lipid metabolism in mice

OBJECTIVES: We evaluated the effects of dietary pomegranate seed oil (PSO), which contains high levels of punicic acid (9c, 11t, 13c-octadecatrienoic acid), on immune function and lipid metabolism in C57BL/6N mice. METHODS: Mice were fed experimental diets containing 0%, 0.12%, or 1.2% PSO for 3 wk. RESULTS: No significant differences were observed between growth patterns of the experimental groups. Splenocytes isolated from mice fed 0.12% or 1.2% PSO produced larger amounts of immunoglobulins G and M but not immunoglobulin A irrespective of stimulation with or without phorbol 12-myristate 13-acetate and the calcium ionophore A23187. Dietary PSO did not affect the percentages of B cells or CD4-positive or CD8-positive T cells in splenocytes. Levels of interleukin-4, interferon-gamma, and tumor necrosis factor-alpha production from splenocytes were comparable among all dietary groups. Analysis of serum lipid parameters showed significant increases in serum triacylglycerol and phospholipid levels but not in total cholesterol in the PSO groups. Serum, liver, epididymal, and perirenal adipose punicic acid levels were high with increases in dietary PSO level. However, punicic acid was not detected in splenocytes for any dietary group. Interestingly, 9c, 11t-conjugated linoleic acid level could be detected in serum, liver, and adipose tissues in mice fed the 0.12% or 1.2% PSO diet. CONCLUSIONS: These results suggest that PSO may enhance B-cell function in vivo.