An antioxidant treatment is able to prevent hypertension and the imbalance of the renin angiotensin system induced by a high sodium diet

KOUYOUMDZIAN NM; CAO G; DELLA PENNA SL; RUKAVINA MIKUSIC NL; CHOI MR; PANDOLFO M; FERNÁNDEZ BE; TOBLLI JE; ROSON MI

Ciudad Autónoma de Buenos Aires

Congreso; III International Congress in Translational Medicine; 2016

Facultad de Farmacia y Bioquímica, University of Freiburg

AIM: Salt sensitivity, which isan increase in blood pressure in response to high dietary salt intake, is an independent risk factorfor cardiovascular disease and mortality. Currentdietary intake of salt in western societies is an important factor for thegenesis of hypertension and may even cause blood pressure-independent targetorgan damage, including the kidney. The aim of this study determine the effectof a high salt diet administered to normal rats on blood pressure and thebalance between antagonist components of the renal renin-angiotensin system andevaluate the preventive action of antioxidant tempol. METHODS: Sprague-Dawley rats were fed with 8% Na Cl (high-salt, HS) or 0.4%NaCl (normal-salt, NS) diet for 3 weeks, with or without tempol (T) (1mM,administered in drinking water). Mean arterial pressure (MAP), glomerularfiltration rate (GFR), and urinary sodium excretion (UVNa) weremeasured. We evaluated Angiotensin II (Ang II), Angiotensin 1-7 (Ang 1-7), AngiotensinConverting Enzyme 2 (ACE2), Mas Receptor (MasR), Angiotensin Type 1 Receptor(AT1R) and Angiotensin Type 2 Receptor (AT2R) in renal tissues byimmunohistochemistry.RESULTS: High sodium dietary produced a slight but significant increase in MAPand differentially regulated components of the renal RAS.This included an increase in Ang II and AT1R, and decrease in ACE-2 stainingintensity using immunohistochemistry. Antioxidant supplementation with tempol increasednatriuresis and glomerular filtration rate, prevented changes in blood pressureand reversed the imbalance of renal RAScomponents. This includes a decrease in Ang II and AT1R, as increase in AT2,ACE2, Ang (1-7) and MasR staining intensity. In addition, the natriuretic effects of tempolwere observed in NS-T group, which showed an increased stainingintensity of AT2, ACE2,Ang (1-7) and MasR.CONCLUSION: Thesefindings suggest that a high salt diet leads to changes in the homeostasisand balance between opposing components of the renal RASfavour greater immunostaining of Ang II and increased blood pressure. Chronicantioxidant supplementation can prevent this imbalance favouring thenatriuretic components of the renal RAS.