Are urinary enzymes useful markers of kidney damage in obstructive jaundice? An experimental study on Sprague-Dawley rats.

To evaluate the reliability of urinary enzymes as markers of renal tubular damage in obstructive jaundice, research was carried out on 26 Sprague-Dawley rats submitted to bile duct ligation and on 16 sham-operated rats. The fractional clearances of lysozyme (CfrLYS) and of malto-dehydrogenase (CfrMDH)-indices of tubular function-and the fractional excretions of gamma-glutamyltransferase (UfrGGT) and of alpha-glucosidase (UfrAGL)-indices of tubular anatomic damage - were measured 5, 10, 20 and 30 days after operation. Creatinine clearance, urinary sodium excretion, urinary potassium excretion, proteinuria, plasma bilirubin and bile acids were also measured. Kidneys were taken for histology. All rats submitted to common bile duct ligation had high levels of bilirubin and bile acids; proximal tubules were damaged and the extent of the lesions increased with time. However, creatinine clearance, urinary sodium excretion, proteinuria, CfrMDH and UfrAGL gave no indication of renal lesions, whereas CfrLYS and UfrGGT were significantly higher 20 and 30 days after bile duct ligation, respectively. These findings show that CfrLYS and UfrGGT could be useful tests for renal tubular lesions in jaundice.