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 rats with unilateral (UPO) and bilateral (BPO) partial ureteral obstruction with the dimercaptosuccinic acid (DMSA) scan as the gold standard for measuring renal tubular damage. We studied 70 female Wistar rats: 28 animals with UPO, 28 animals with BPO, 7 sham-operated animals, and 7 controls. All animals with obstructed ureters showed renal dilatation on the diethylenetriaminepentaacetic acid DTPA images 1 and 5 weeks postoperatively. One week following UPO and BPO, tubular proteinuria and urinary N-acetyl-beta-D-glucosaminidase (NAG) activity increased (P < 0.01) and the absolute DMSA uptake decreased (P < 0.01). Persistently (week 6) high tubular proteinuria was found 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 demonstrated by measuring renal enzymes, tubular proteins, and DMSA uptake after UPO and BPO. Persistent elevated tubular proteinuria was related to severely damaged kidneys.