AIM To determine the effect of tempol in normal rats fed high salt on arterial pressure and the balance between antagonist components of the renal renin-angiotensin system.METHODS Sprague-Dawley rats were fed with 8% ...AIM To determine the effect of tempol in normal rats fed high salt on arterial pressure and the balance between antagonist components of the renal renin-angiotensin system.METHODS Sprague-Dawley rats were fed with 8% NaCl high-salt （HS） or 0.4% NaCl （normal-salt, NS） diet for 3 wk, with or without tempol （T） （1 mmol/L, administered in drinking water）. Mean arterial pressure （MAP）, glomerular fltration rate （GFR）, and urinary sodium excretion （UVNa） were measured. We evaluated angiotensin Ⅱ （Ang Ⅱ）, angiotensin 1-7 （Ang 1-7）, angiotensin converting enzyme 2 （ACE2）, mas receptor （MasR）, angiotensin type 1 receptor （AT1R） and angiotensin type 2 receptor （AT2R） in renal tissues by immunohistochemistry.RESULTSThe intake of high sodium produced a slight but signifcant increase in MAP and differentially regulated components of the renal renin-angiotensin system （RAS）. This included an increase in Ang Ⅱ and AT1R, and decrease in ACE-2 staining intensity using immunohistochemistry. Antioxidant supplementation with tempol increased natriuresis and GFR, prevented changes in blood pressure and reversed the imbalance of renal RAS components. This includes a decrease in Ang Ⅱ and AT1R, as increase in AT2, ACE2, Ang （1-7） and MasR staining intensity using immunohistochemistry. In addition, the natriuretic effects of tempol were observed in NS-T group, which showed an increased staining intensity of AT2, ACE2, Ang （1-7） and MasR.CONCLUSION These findings suggest that a high salt diet leads to changes in the homeostasis and balance between opposing components of the renal RAS in hypertension to favour an increase in Ang Ⅱ. Chronic antioxidant supplementation can modulate the balance between the natriuretic and antinatriuretic components of the renal RAS.展开更多
基金Supported by A grant from the Universidad de Buenos Aires(UBACYT 20020130200105BA)
文摘AIM To determine the effect of tempol in normal rats fed high salt on arterial pressure and the balance between antagonist components of the renal renin-angiotensin system.METHODS Sprague-Dawley rats were fed with 8% NaCl high-salt （HS） or 0.4% NaCl （normal-salt, NS） diet for 3 wk, with or without tempol （T） （1 mmol/L, administered in drinking water）. Mean arterial pressure （MAP）, glomerular fltration rate （GFR）, and urinary sodium excretion （UVNa） were measured. We evaluated angiotensin Ⅱ （Ang Ⅱ）, angiotensin 1-7 （Ang 1-7）, angiotensin converting enzyme 2 （ACE2）, mas receptor （MasR）, angiotensin type 1 receptor （AT1R） and angiotensin type 2 receptor （AT2R） in renal tissues by immunohistochemistry.RESULTSThe intake of high sodium produced a slight but signifcant increase in MAP and differentially regulated components of the renal renin-angiotensin system （RAS）. This included an increase in Ang Ⅱ and AT1R, and decrease in ACE-2 staining intensity using immunohistochemistry. Antioxidant supplementation with tempol increased natriuresis and GFR, prevented changes in blood pressure and reversed the imbalance of renal RAS components. This includes a decrease in Ang Ⅱ and AT1R, as increase in AT2, ACE2, Ang （1-7） and MasR staining intensity using immunohistochemistry. In addition, the natriuretic effects of tempol were observed in NS-T group, which showed an increased staining intensity of AT2, ACE2, Ang （1-7） and MasR.CONCLUSION These findings suggest that a high salt diet leads to changes in the homeostasis and balance between opposing components of the renal RAS in hypertension to favour an increase in Ang Ⅱ. Chronic antioxidant supplementation can modulate the balance between the natriuretic and antinatriuretic components of the renal RAS.
