Submitted on May 21, 2008
Revised on November 13, 2008
Accepted on December 1, 2008
Omega-3 fatty acid rich diet prevents diabetic renal disease
Joseph H Garman1, Susan E. Mulroney2, Michaele Manigrasso3, Elizabeth Flynn3, and Christine Maric3*
1 Georgetown University Medical Center
2 Georgetown University School of Medicine
3 University of Mississippi
* To whom correspondence should be addressed. E-mail: Cmaric{at}physiology.umsmed.edu.
Omega-3 polyunsaturated fatty acids (n-3 PUFA) show beneficial effects in cardiovascular disease, IgA and diabetic nephropathy, however, the mechanisms underlying these benefits are unknown. The study was performed in male Sprague-Dawley rats randomly divided into 4 treatment groups: non-diabetic (ND), streptozotocin-induced diabetic (D), diabetic fed a high n-3 PUFA diet (D+canola), and diabetic fed a high n-6 (omega-6) PUFA diet (D+corn). Study treatments were carried out for 30 weeks. D+canola significantly decreased diabetes-associated increases in urine albumin excretion (ND 17.8±6.4; D 97.3±9.4; D+canola 8.3±2.2 mg/day); systolic blood pressure (ND 153±9; D 198±7; D+canola 162±9 mmHg); glomerulosclerosis (ND 0.6±0.2; D 1.8±0.2; D+canola 0.8±0.1; AU); and tubulointerstitial fibrosis in the renal cortex (ND 1.2±0.2; D 2.0±0.2; D+canola 1.1±0.1) and the inner stripe of the outer medulla (ND 1.0±0.2; D 2.1±0.2; D+canola 1.1±0.2). D+corn also exerted renoprotection, but not to the same degree as D+canola (urine albumin excretion, 33.8±6.1 mg/day; systolic blood pressure, D+corn 177±6 mmHg; glomerulosclerosis, D+corn 1.2±0.3 AU; cortical tubulointerstitial fibrosis, D+corn 1.6±0.1 AU; medullary tubulointerstitial fibrosis, D+corn 1.5±0.1 AU). In addition, D+canola attenuated D-associated increase in collagen type I and type IV, IL-6, MCP-1, TGF-
and CD68 expression. These observations indicate a beneficial effect of high dietary intake of n-3 PUFA on reducing diabetic renal disease.
