Eplerenone-mediated aldosterone blockade prevents renal fibrosis by reducing renal inflammation, interstitial cell proliferation and oxidative stress.

BACKGROUND/AIMS Prolonged elevation of serum aldosterone leads to renal fibrosis. Inflammation also plays a role in the pathogenesis of renal disease. We used a rat model of interstitial renal fibrosis to test the hypothesis that eplerenone-mediated aldosterone blockade prevents renal fibrosis due to its anti-inflammatory and anti-proliferative effects. METHODS Eplerenone (a selective aldosterone blocker) or vehicle (control), was given to male Wistar rats (50 mg/kg, twice daily) for 7 days before unilateral ureteral obstruction (UUO) and for an additional 28 days after surgery. Body weight, blood pressure, renal histo-morphology, immune-staining for macrophages, monocyte chemotactic protein-1, proliferating cell nuclear antigen, α-smooth muscle actin, and serum and urine markers of renal function and oxidative stress were determined for both groups on 7, 14, and 28 days after surgery. RESULTS Epleronone had no effect on body weight or blood pressure. However, eplerenone inhibited the development of renal fibrosis, inflammation (macrophage and monocyte infiltration), interstitial cell proliferation, and activation of interstitial cells (α-SMA expression). Epleronone also reduced oxidative stress. CONCLUSION The anti-fibrotic effect of eplerenone appears to be unrelated to its effect on blood pressure. Eplerenone inhibits renal inflammation, interstitial cell proliferation, phenotypic changes of interstitial cells, and reduces oxidative stress.