P44: Nitric oxide may modulate matrix metalloproteinase-2 during renovascular hypertension

Abstract

Decreased nitric oxide (NO) bioavailability and up-regulated MMP activity contribute to hypertension-induced cardiovascular hypertrophy. However, it is uncertain whether NO affects MMP activity. Dietary nitrite is an alternative source of NO and may exert antioxidant effects, thus affecting up-regulated MMP hypertension. We evaluated whether sodium nitrite treatment reduces cardiac MMP in 2-kidney, 1-clip (2K1C) hypertension. Sham and 2K1C rats were treated with vehicle or sodium nitrite (15 mg/kg orally) for 4 weeks. Systolic blood pressure was monitored weekly. Plasma nitrite concentrations were analyzed by chemiluminescence. Cardiac MMP level/activity were determined by gelatin and in situ zymography. Sodium nitrite treatment exerted antihypertensive effects in 2K1C rats ( P < 0.05). We found lower plasma nitrite concentrations in 2K1C rats when compared with the Sham group ( P < 0.05), and nitrite treatment restored these levels in 2K1C rats. 2K1C hypertension increased cardiac MMP-2 levels and MMP activity ( P < 0.05). Sodium nitrite treatment reduced hypertension-induced increases in both MMP levels and activity ( P < 0.05). Our results suggest that sodium nitrite treatment prevents 2K1C hypertension-induced MMP up-regulation, and therefore may prevent cardiac remodeling associated with hypertension. Supported by: FAPESP, CNPq. Nothing to disclose.