Spironolactone Improves Angiotensin-Induced Vascular Changes and Oxidative Stress

Abstract
Angiotensin II plays an important role in vascular remodeling. We investigated the role of aldosterone, which is stimulated by angiotensin II, as a mediator of angiotensin II–induced vascular structural and functional alterations. Sprague-Dawley rats (n=8 to 12/group) received angiotensin II (120 ng/kg per minute, subcutaneously) for 14 days ± spironolactone or hydralazine (25 mg/kg per day). An additional group received aldosterone (750 ng/h, subcutaneously) ± spironolactone. Systolic blood pressure was increased by angiotensin II ( P P P P P P P P P P P <0.001), were normalized by spironolactone. In conclusion, spironolactone, which inhibited aldosterone actions, partially corrected structural and functional angiotensin II–induced abnormalities. These effects were associated with reduced vascular NADPH oxidase activity and decreased plasma markers of oxidative stress. Our findings suggest that aldosterone may mediate some of angiotensin II–induced vascular effects in hypertension, in part via increased oxidative stress.