SELECTIVE DIETARY RESTRICTION OF PROTEIN AND CALORIE INTAKES PREVENTSSPONTANEOUS PROTEINURIA IN MALE MWF RATS

Background/Aims: Previous observations indicate that protein and calor ie restrictions can affect the course of renal disease progression. We compared the effects of selective protein and calorie restriction on glomerular hemodynamics and proteinuria in a model of spontaneous glom erular injury in the rat. Methods: Three groups of male MWF rats were assigned to three different diets: standard diet (ST, 19% protein, 3.4 kcal/g), low protein (LP) and low calorie (LC). Proteinuria and systo lic blood pressure were periodically measured. Glomerular hemodynamics and tuft volume were determined after 2 months of dietary treatment. Results: The effective mean protein intake was 3.4 +/- 0.4, 1.6 +/- 0. 2, and 3.2 +/- 0.2 g/day/rat, respectively, for the ST, LP, and LC die ts, while caloric intake averaged 60 +/- 7, 59 +/- 9, and 30 +/- 2 kca l/day/rat. Both LP and LC diets significantly prevented proteinuria (1 04 +/- 32, 36 +/- 9, and 18 +/- 8 mg/day, respectively, in the three g roups). The systolic blood pressure was unaffected by the diets. The L C diet induced lower body and kidney weights than the ST diet. The glo merular filtration rate was slightly but significantly increased by th e LP diet, but not by the LC diet (0.64 +/- 0.14, 0.81 +/- 0.08, and 0 .67 +/- 0.12 ml/min, respectively, for ST, LP and LC diets). The glome rular hydraulic pressures were not affected by the diets. No differenc es were also observed in glomerular volume. The incidences of glomerul osclerosis and tubulointerstitial changes were comparable in ST and LP diets and completely absent in the LC diet group. Conclusion: These r esults indicate that restriction of both protein and calorie intakes p revents spontaneous proteinuria in male MWF rats by preventing deterio ration of glomerular perm-selective functions.