Effects of Fish Oil and α-Tocopherol in Immunoglobulin A Nephropathy in the Rat

Top of pageAbstract α-Tocopherol and fish oil have been reported to modulate the progression of IgA nephropathy in animals and humans. Because fish oil has been reported to exacerbate renal disease in subtotal nephrectomized rats, we investigated the effects of fish oil, with and without α-tocopherol, on the course of IgA nephropathy. Experimental IgA nephropathy was induced in male Sprague-Dawley rats, weighing 170-200 g, by oral and i.v. immunization with bovine γ-globulin for 8 wk. IgA nephropathy was evidenced by hematuria, proteinuria, and IgA deposition in the mesangium. Standard rodent chow, containing 30 IU of α-tocopherol/kg of diet, was given to the control and IgA nephropathy rats. Fish oil (20% wt/wt), stripped ofα-tocopherol preservative, was given to control and a second group of IgA nephropathy rats. Alternatively, corn oil or fish oil was supplemented with α-tocopherol at 100 IU/kg of diet and given to the third and fourth groups of IgA nephropathy rats. All animals were killed at 8 wk. Urinary protein excretion, plasma and kidney α-tocopherol concentrations, as well as glomerular planar area, and kidney transforming growth factor-β1 mRNA were analyzed. As determined by reductions in proteinuria, glomerular planar area, and TGF-β1 mRNA, fish oil with α-tocopherol ameliorated the renal injury induced by bovineγ-globulin, whereas fish oil without α-tocopherol did not. Our findings support the importance of α-tocopherol, more so than fish oil, in mitigating the injury and promoting repair in experimental IgA nephropathy. Abbreviations: BGG, bovine γ-globulin; TGF-β1, transforming growth factorβ1; TBHQ, tertiary butylhydroquinone