ABSTRACT
Adriamycin, a commonly used antineoplastic antibiotic, induces glomerular lesions in rats, resulting in persistent proteinuria and glomerulosclerosis. We studied the effects of dietary protein and of an angiotensin I converting enzyme inhibitor on the progression of this nephropathy and the evolution of the histological lesions, as well as mesangial macromolecule flow. Adriamycin nephropathy was induced by injecting a singl iv dose of adriamycin (3 mg/kg body weight) into the tail vein of male wistar rats (weight, 180-200 g). In Experiment I animals with adriamycin-induced nephropathy were fed diets containing 6 percent (Low-Protein Diet Group = LPDG), 20 percent (Normal-Protein Diet Group = NPDG) and 40 percent (High-Protein Diet Group = HPDG) protein and were observed for 30 weeks. In Experiment II the rats with adriamycin nephropathy were divide into 2 groups: ADR, that received adriamycin alone, and ADR-ENA, that received adriamycin plus enalapril, an angiotensin I converting enzyme inhibitor. The animals were sacrificed after a 24-week observation period. Six hours before sacrifice the animals were injected with 131I-ferritin and the amount of 131I-ferritin in the glomeruli was measured. In Experiment III, renal histology was performed 4, 8 and 16 weeks after adriamycin injection. At the end of Experiment I the tubulointerstitial lesion index was 2 for LPDG, 8 for NPDG, and 7.5 for HPDG (P,0.05); the frequency of glomerulosclerosis was 19 + or - 6.1 percent in LPDG, 42.6 + or - 6 percent in NPDG, and 54 + or - 9 percent in HPDG (P,0.05); and proteinuria was 61.1 + or - 25 mg/24 h in LPDG, 218.7 + or - 27.5 mg/24 h in NPDG, and 324.5 + or - 64.8 mg/24 h in HPDG (P,0.05). In Experiment II, at sacrifice, 24-h proteinuria was 189 + or - 16.1 mg in ADR, and 216 + or - 26.1 mg in ADR-ENA (P.0.05); the tubulointerstitial lesion index was 5 for ADR, and 5 for ADR-ENA (P.0.05); the frequency of glomerulosclerosis was 40 + or - 5.2 percent in ADR and 44 + or - 6 percent in ADR-ENA (P.0.05); the amount of 131I-ferritin in the mesangium was 214.26 + or - 22.71 cpm/mg protein in ADR and 253.77 + or - 69.72 cpm/mg protein in ADR-ENA (P.0.05). In Experiment III, sequential histological analysis revealed an acute tubulointerstitial cellular infiltrate at week 4, whigh was decreased at week 8. Tubular casts and dilatation were first seen at week 8 and increased at week 16 when few glomerular lesions were found. The results suggest that the tubulointerstitial lesions may play a role in the development of glomerulosclerosis in adriamycin-induced nephropathy