Late feeding of dietary fish oil alleviates disease severity and affects macrophage function in autoimmune NZB/W F1 mice.

To investigate the influence of different saturations of dietary fat on autoantibody production and disease courses, autoimmune NZB/NZW F1 (NZB/W F1) mice were fed diets containing 20% palm oil, lard/soybean oil, soybean oil, canola oil or fish oil at 5 months of age. Sera levels of anti-DNA antibodies, proteinuria and life span were followed regularly. In addition, peritoneal resident cells were isolated and mediators such as interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), prostaglandin E2 (PGE2) and NO production were measured. The results show that mice fed a diet containing with fish oil had significantly decreased immunoglobulin G (IgG) anti-single strand (ss) or double strand (ds) DNA antibody levels, lessened proteinuria and prolonged life span compared to mice fed diets containing other types of dietary fat. TNF-alpha and PGE2 levels in mice fed a diet containing fish oil were significantly lower compared to the other dietary groups. IL-6 and NO produced by peritoneal resident cells were significantly higher in mice fed a diet containing lard/soybean oil in comparison with mice of the other groups. Hepatic ex vivo PGE2 level was significantly lower in mice fed fish oil compared to mice of the other dietary groups. These data suggested that dietary fish oil might affect either autoantibody production or macrophage function, contributing to alleviation of the autoimmune process in autoimmune-prone NZB/W F1 mice.