SALT RESTRICTION INHIBITS RENAL GROWTH AND STABILIZES INJURY IN RATS WITH ESTABLISHED RENAL-DISEASE

Salt restriction inhibits renal growth and stabilizes injury in rats w ith established renal disease, Male Munich-Wistar rats that underwent right nephrectomy and segmental infarction of two thirds of the left k idney were fed standard chow for 4 wk and then randomly assigned to in gest standard or low-salt chow for an additional 4 wk, Four wk after a blation, rats had systemic hypertension, proteinuria, and glomerular s clerosis. The prevalence of sclerosis, protein excretion rate, and glo merular volume increased between the fourth and eighth week in rats th at were fed standard chow, however, in rats that were fed low-salt cho w, the increase in glomerular volume and development of further glomer ular sclerosis was prevented whereas the protein excretion rate actual ly declined. Micropuncture studies performed 8 wk after ablation revea led that the glomerular hydraulic pressure was elevated in remnant kid neys and was not affected by salt restriction. This study demonstrates that dietary salt restriction can prevent further glomerular injury a nd reduce proteinuria even when instituted in rats with established re nal disease. These findings are also consistent with the hypothesis th at glomerular hypertrophy promotes injury in this model of hypertensio n and progressive renal disease.