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This Article Full Text Full Text (PDF) All Versions of this Article: 294/6/F1323    most recent 00401.2007v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Diaz Encarnacion, M. M. Articles by Grande, J. P. PubMed PubMed Citation Articles by Diaz Encarnacion, M. M. Articles by Grande, J. P.

Signaling pathways modulated by fish oil in salt-sensitive hypertension

¹Department of Laboratory Medicine and Pathology and ²Division of Nephrology, Mayo Clinic College of Medicine, Rochester, Minnesota

Submitted 29 August 2007 ; accepted in final form 1 April 2008

Although many studies have indicated that fish oil (FO) improves cardiovascular risk factors and reduces histopathological manifestations of injury in experimental renal injury models, potential mechanisms underlying this protective effect have not been adequately defined. The objective of this study was to identify potential signaling pathways that confer protection in the Dahl rat model of salt-sensitive hypertension. Male Dahl salt-sensitive rats (n = 10/group) were provided with formulated diets containing 8% NaCl, 20% protein, and 25% FO or 25% corn oil (CO) for 28 days. FO reduced blood pressure (–11% at 4 wk; P < 0.05), urine protein excretion (–45% at 4 wk; P < 0.05), plasma cholesterol and triglyceride levels (–54%, P < 0.001; and –58%, P < 0.05), and histopathological manifestations of renal injury, including vascular hypertrophy, segmental and global glomerular sclerosis, interstitial fibrosis, and tubular atrophy. Interstitial inflammation was significantly reduced by FO (–32%; P < 0.001), as assessed by quantitative analysis of ED1-positive cells in sections of the renal cortex. FO reduced tubulointerstitial proliferative activity, as assessed by Western blot analysis of cortical homogenates for PCNA (–51%; P < 0.01) and quantitative analysis of Mib-1-stained sections of the renal cortex (–42%; P < 0.001). Decreased proliferative activity was associated with reduced phospho-ERK expression (–37%; P < 0.005) and NF-B activation (–42%; P < 0.05). FO reduced cyclooxygenase (COX)-2 expression (–63%; P < 0.01) and membrane translocation of the NADPH oxidase subunits p47^phox and p67^phox (–26 and –34%; P < 0.05). We propose that FO ameliorates renal injury in Dahl salt-sensitive rats through the inhibition of ERK, decreased NF-B activation, inhibition of COX-2 expression, and decreased NADPH oxidase activation.

fibrosis; glomerulosclerosis; docosahexaenoic acid; eicosapentaenoic acid; rat