A new model of genetic hypertension in rats with superficial glomeruli

Despite renal involvement in the genesis of hypertension, the precise renal hemodynamic events prior to and during development of hypertension have not been obtainable by direct study in the available rat models of genetic hypertension. We have developed a model of genetic salt-sensitive hypertension in rats with superficial glomeruli, using the protocol described by Dahl to develop the Brookhaven model. Adult Munich Wistar rats were purchased from Charles River and bred in our laboratory. Offspring were allowed to mature without intervention. Systolic blood pressure and body weight were measured weekly to determine the normal longitudinal changes with increasing age for this strain. Balance studies were also carried out longitudinally, and during these studies plasma renin activity (PRA) was determined. When the rats were 16 weeks old, the availability of superficial glomeruli was assessed under microscopic examination and only those rats with numerous superficial glomeruli/field were mated. The offspring of these breeders were used as the zero generation (F0) of salt-sensitive rats, and were treated as described by Dahl. Systolic blood pressure, body weights and balance studies were carried out in this and in all subsequent generations. Sibling breeding was maintained and rats were bred for salt-sensitivity (systolic blood pressure greater than 155 mmHg at the age of 2 months) and availability of superficial glomeruli. Those rats with systolic blood pressure of less than 120 mmHg were bred in an attempt to develop a salt-resistant strain, and untreated Munich Wistar rats were bred to provide another control.(ABSTRACT TRUNCATED AT 250 WORDS)