Development of renal lesions in dogs after 11/12 reduction of renal mass. Influences of dietary protein intake.
Renal failure was induced in 15 normal Beagle dogs by ligation of approximately 5/6 of the renal arteries of the left kidney and contralateral nephrectomy in order to determine how: (a) 11/12 reduction in total renal mass influences urine protein excretion and renal morphology in dogs, and (b) dietary protein intake influences renal function, urine protein excretion, and renal morphology in canine renal failure. Dogs were fed a reduced protein diet for 12 weeks after induction of renal failure, while compensatory renal hypertrophy developed. Renal function was then evaluated and dogs were distributed into 2 groups with approximately equal degrees of renal dysfunction. One group was fed a high protein diet (42% protein) and a second group was fed moderately restricted protein diets (18% protein). After 8 weeks, renal function, magnitude of proteinuria, and renal morphology were re-evaluated. Inulin clearance increased in all dogs fed the 42% protein diet and 3 of 10 dogs fed the 18% protein diets. Proteinuria was significantly greater in dogs fed the high protein diet than dogs fed the reduced protein diets. Compared with previously nephrectomized contralateral control kidneys, glomerular sclerosis and renal interstitial lesions had developed in all dogs, regardless of severity of renal dysfunction or diet fed. Although reduced dietary protein intake did not prevent development of renal lesions, renal lesions were significantly more severe in the 5 dogs fed the 42% protein diet and 3 dogs fed the 18% protein diets in which inulin clearance increased, than in 7 dogs fed the reduced protein diets in which inulin clearance did not increase.