Dietary fish oil reduces progression of established renal disease in (NZB x NZW)F1 mice and delays renal disease in BXSB and MRL/1 strains.

Previous studies have shown that dietary marine lipids containing large quantities of n-3 polyunsaturated fatty acids, administered to (New Zealand black X New Zealand white)F1 and MRL-lpr/lpr mice before the development of renal disease, reduce the severity of glomerulonephritis in mice of these strains. The present study demonstrated that delayed administration of a marine lipid diet, 25% menhaden oil (MO) by weight, until after the onset of overt renal disease, also resulted in significant improvement in rates of mortality, proteinuria, and histologic evidence of glomerular injury, compared with control animals fed a diet that contained mostly saturated fatty acids, 25% beef tallow. The MO diet also reduced the histologic severity of renal disease in male BXSB/MpJ and male MRL-lpr/lpr mice. In contrast, necrotizing vasculitis was more frequent in small and medium-sized renal arteries of the MRL-lpr/lpr mice fed MO than in those fed beef tallow (33.4% versus 7.6%, respectively).