Possible Contributions of Reactive Oxygen Species and Mitogen-Activated Protein Kinase to Renal Injury in Aldosterone/Salt-Induced Hypertensive Rats

Abstract
Studies were performed to test the hypothesis that reactive oxygen species (ROS) and mitogen-activated protein kinase (MAPK) contribute to the pathogenesis of aldosterone/salt-induced renal injury. Rats were given 1% NaCl to drink and were treated with one of the following combinations for 6 weeks: vehicle (0.5% ethanol, SC, n=6); aldosterone (0.75 μg/H, SC, n=8); aldosterone plus a selective mineralocorticoid receptor antagonist; eplerenone (0.125% in chow, n=8); aldosterone plus an antioxidant; and tempol (3 mmol/L in drinking solution, n=8). The activities of MAPKs, including extracellular signal-regulated kinases (ERK)1/2, c-Jun-NH2-terminal kinases (JNK), p38MAPK, and big-MAPK-1 (BMK1) in renal cortical tissues were measured by Western blot analysis. Aldosterone-infused rats showed higher systolic blood pressure (165±5 mm Hg) and urinary excretion of protein (106±24 mg/d) than vehicle-infused rats (118±3 mm Hg and 10±3 mg/d). Renal cortical mRNA expression of p22phox, Nox-4, and gp91phox, measured by...