Uninephrectomy in Young Age or Chronic Salt Loading Causes Salt-Sensitive Hypertension in Adult Rats

• Published in: Hypertension (Dallas, Tex. 1979) Vol. 49; no. 6; pp. 1342 - 1350
• Main Authors: Carlström, Mattias, Sällström, Johan, Skøtt, Ole, Larsson, Erik, Persson, A Erik G
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA American Heart Association, Inc 01.06.2007; Hagerstown, MD Lippincott
• Subjects: Aging - pathology; Animals; Arterial hypertension. Arterial hypotension; Biological and medical sciences; Blood and lymphatic vessels; blood pressure; Blood Pressure - physiology; Cardiology. Vascular system; cardiovascular diseases; Clinical manifestations. Epidemiology. Investigative techniques. Etiology; Experimental diseases; fibrosis; glomerular filtration rate; Glomerular Filtration Rate - physiology; Hypertension - etiology; Hypertension - physiopathology; hypertension renal; Hypertrophy - pathology; Kidney - pathology; Male; Medical sciences; MEDICIN; Medicin och hälsovetenskap; MEDICINE; Myocardium - pathology; nephrectomy; Nephrectomy - adverse effects; Nephrons - physiopathology; Rats; Rats, Sprague-Dawley; Renin - blood; sodium dietary; Sodium, Dietary - adverse effects; Diuresis; Glomerular filtration; Renal function; Rat; Cardiovascular disease; hypertension renal; Renin; sodium dietary; Nephrectomy; Arterial pressure; Aspartic endopeptidases; Blood pressure; Human; Hypertension; Enzyme; glomerular filtration rate; Rodentia; cardiovascular diseases; Peptidases; Vertebrata; Anatomic pathology; Mammalia; Sodium; Adult animal; Fibrosis; Nephron; Hydrolases; Comparative study
• ISSN: 0194-911X; 1524-4563; 1524-4563
• DOI: 10.1161/HYPERTENSIONAHA.107.087213

The importance of nephron endowment and salt intake for the development of hypertension is under debate. The present study was designed to investigate whether reduced nephron number, after completion of nephrogenesis, or chronic salt loading causes renal injury and salt-sensitive hypertension in adulthood. Rats were operated at 3 weeks of age (after completed nephrogenesis) and then subjected to either normal or high-salt diets for 6 to 8 weeks. Four different experimental groups were usedsham-operated animals raised with normal-salt diet (controls) or high-salt diet (HS) and uninephrectomized animals raised with normal-salt diet (UNX) or high-salt diet (UNX+HS). In the adult animals, renal and cardiovascular functions were evaluated and blood pressure recorded telemetrically under different sodium conditions (normal, high, and low). Hypertension was present in UNX+HS (122±9 mm Hg), UNX (101±3 mm Hg), and HS (96±1 mm Hg) groups on normal-salt diets compared with the controls (84±2 mm Hg), and the blood pressure was salt sensitive (high- versus normal-salt diet; 23±3, 9±2, 7±2, and 1±1 mm Hg, respectively). The hypertensive groups (UNX+HS, UNX, and HS) had increased diuresis and reduced ability to concentrate urine. The glomerular filtration rate (milliliters per minute) in anesthetized rats was reduced in the UNX+HS (2.36±0.30) and UNX animals (2.00±0.31) compared with both HS animals (3.55±0.45) and controls (3.01±0.35). Hypertensive groups displayed reduced plasma renin concentrations during high sodium conditions and hypertrophic kidneys and hearts with various degrees of histopathologic changes. In conclusion, at a young age after completed nephrogenesis, uninephrectomy or chronic salt loading causes renal and cardiovascular injury with salt-sensitive hypertension.