Characterization of chronic N,N'-diacetylbenzidine-induced nephropathy.

Rats given N,N'-diacetyl benzidine (N,N'-DAB) by intraperitoneal injections were studied to further characterize the ensuing renal disease. Significant proteinuria and albuminuria occurred at 10 weeks and thereafter and was enhanced by prior unilateral nephrectomy. Glomerular epithelial cell vacuolization and cyst formation were marked in proteinuric rats. Focal glomerular sclerosis and synechia were present, but proliferative crescent formation was not. Glomerular fibrinogen was noted, but no immunoglobulins or C3 was detected by immunofluorescence microscopy. Glomerular epithelial cell cysts and disruption were noted ultrastructurally, but no electron-dense deposits were seen. Tubular basement membrane thickening and wrinkling were noted in N,N'-DAB rats, and maximum urine osmolarlity was decreased. None of the animals developed renal insufficiency. Parenteral N,N'-DAB-induced renal disease is different from crescentic glomerulonephritis noted in rats fed N,N'-DAB and has similarities to an experimental model of aminonucleoside induced focal sclerosis, supporting the theory of primary glomerular epithelial cell injury mediating proteinuria and focal sclerosis.