Dietary supplementation of fish oil rich in eicosapentaenoic acid enhances bovine serum albumin induced immune complex nephritis in NZB/W F1 mice

Abstract

In order to evaluate the effects ofw-3 polyunsaturated fatty acid on BSA nephritis in female NZB/W F1 mice, animals were fed a diet containing fish oil (FO), safflower oil (SO) or beef tallow (BT) as a lipid source. After preimmunization 4 times with BSA, 50 mg/kg of BSA was given intraperitoneally every day for 4 weeks. Proteinuria was demonstrated in 50% of FO (n=18), in 33% of BT (n=21), but only in 5% of SO (n=19,p<0.005 vs. FO,p<0.05 vs. BT) animals. Anti-BSA antibodies did not differ among the three groups. Circulating BSA-anti BSA immune complexes (log₂ of the ratio to pooled standard sera) were −1.3±0.3 in FO, −2.2±0.4 in SO and −2.7±0.5 in BT (p<0.05 vs. FO) at sacrifice at 18 weeks of age. Prostaglandin E₂ and thromboxane B₂ production by mashed renal cortex was markedly suppressed in FO (p<0.001, vs. SO and BT). By light microscopy, FO showed more glomerular hypercellularity and mesangial increase than SO (p<0.001). By immunofluorescence and electron microscopy, heavier mesangial and loop or subepithelial deposits were seen in FO than in SO (p<0.005). Fish oil may be involved in immune complex formation and its clearance by suppressed prostanoid production, resulting in enhanced BSA nephritis.