Short- and long-term effects of fish oil on proteinuria, morphology and renal hemodynamics in the Milan normotensive rat model of spontaneous glomerulosclerosis

Background/Aims: A diet rich in polyunsaturated Omega 3 fatty acids has bee n shown to modulate the course of several experimental models of renal dise ase. The short- and long-term effects of an 8% fish oil (FO) chow on protei nuria, renal blood flow and glomerular morphology were evaluated in Milan n ormotensive rats that spontaneously develop progressive glomerulosclerosis. Methods: Eight rats each were pairfed FO- versus cholesterol-enriched or c ontrol diets for either 2 or 32 weeks. 4/48 animals died (2-week trial: ? r at on the FO and 1 rat on the control diet: 32-week trial: 1 rat on the cho lesterol and 1 rat on the control diet) and were excluded from all statisti c analyses. Results. After 2 weeks the renal blood flows were higher in the FO animals versus controls (8.75+/-2.19 vs. 6.87+/-1.91 ml/min/g, p<0.05), and the prostaglandin E-2/thromboxane B-2 ratio shifted towards the vasodi latative prostaglandin E-2 (1.76+/-0.18 vs. 0.91+/-0.19, p<0.05). During th e long-term trial proteinuria in the FO animals progressed faster and to a higher level (176.5+/-32.2 vs. 82.7+/-36.7 mg/24 h at week 32, p<0.01). Aft er 32 weeks the renal blood flow was significantly lower in th FO group 2.8 +/-1.1: vs. 4.6+/-1.9 ml/min/g, (p<0.05), and the rats had an accelerated d evelopment of nephrosclerosis, with sclerotic lesions in 60.3+/-6.6% of the glomeruli as compared with 46.5+/-9.8% in the cholesterol and 39.8+/-5.9 i n the control group (p<0.05). Conclusion: The short-time effects of FO on r enal hemodynamics did not alleviate the progress of renal damage in Milan n ormotensive rats, but the morphologic, and functional signs of injury were rather pronounced with FO feeding.