Urinary excretion of tubular proteins and the technetium-99m dimercaptosuccinic acid (DMSA) absolute renal uptake in partial ureteral obstruction in rats: a functional evaluation of hydronephrotic kidneys

The aim of this longitudinal study was to evaluate tubular proteinuria in r ats with unilateral (UPO) and bilateral (BPO) partial ureteral obstruction with the dimercaptosuccinic acid (DMSA) scan as the gold standard for measu ring renal tubular damage. We studied 70 female Wistar rats: 28 animals wit h UFO, 28 animals with BPO, 7 sham-operated animals, and 7 controls. All an imals with obstructed ureters showed renal dilatation on the diethylenetria minepentaacetic acid DTPA images 1 and 5 weeks postoperatively. One week fo llowing UFO and BPO, tubular proteinuria and urinary N-acetyl-beta-D-glucos aminidase (NAG) activity increased (P < 0.01) and the absolute DMSA uptake decreased (P < 0.01). Persistently (week 6) high tubular proteinuria was fo und in 29% of the animals and was related to severe damage on the DMSA scan (P < 0.01) and to albuminuria (P < 0.05). Renal tubular damage was demonst rated by measuring renal enzymes, tubular proteins, and DMSA uptake after U FO and BPO. Persistent elevated tubular proteinuria was related to severely damaged kidneys.