Cardiac and Kidney Weight Indices following Dietary Salt Loading and/or Chronic Nitric Oxide Synthase Inhibition in the Hooded (Aguti) Rat

Abstract

This study was designed to investigate if dietary salt-loading and/or chronic Nitric Oxide Synthase (NOS) inhibition are associated with cardiac hypertrophy and changes in renal mass in the hooded (Aguti) rat. Hooded rats 8-10 weeks old were divided into 4 groups viz: control, salt, L-NAME (N?-L-Arginine Methyl Ester) and salt + L-NAME. Control rats were given a normal rat diet and water. Hypertension was induced in hooded rats by giving the following treatments: rats in the salt group were given an 8% NaCl diet and water for 6 weeks; rats in the L-NAME group were fed the normal rat diet and given water containing L-NAME at a dose of 100mg/Kg/day for 4 weeks; rats in the salt + L-NAME group were given both treatments. The rats (n = 8 per group) were anaesthetized and the hearts and kidneys excised. The cardiac weight indices and the kidney weights were measured. The cardiac weight, cardiac weight index, left and right ventricular weight indices and kidney weight showed no significant difference in the test groups compared to control. Kidney weight/body weight (g/100g body weight) increased significantly (P<0.05) in salt+L-NAME rats (0.35 +/- 0.015) compared to control (0.31 +/- 0.013), salt-loaded (0.29 +/- 0.013) and L-NAME rats (0.20 +/- 0.010). Six weeks of dietary salt-loading and /or four weeks of L-NAME-loading were not associated with cardiac hypertrophy in the hooded rat. However a combination of both manoeuvres resulted in renal hypertrophy.