Renal functional alterations in extrahepatic cholestasis: can oxidative stress be involved?

Renal function may be compromised by extrahepatic cholestasis. In this context, the nephrotoxic role of bile salts is well known. Recently, however, it has been claimed that other factors, such as lipid peroxides, are involved. We therefore created bile duct ligation in 40 Sprague-Dawley rats. During the follow-up (from 1 to 28 days), significant variations were found in liver histological parameters, but not in renal morphology. Fourteen days after ligation, significant increases were found in serum and urinary thiobarbituric-acid-reactive species and phospholipase A2 (indirect indices of lipid peroxidation), whereas 8-10 days after ligation, a significant decrease was observed in erythrocytic and hepatic GSH levels. The variations in urinary thiobarbituric-acid-reactive species and in phospholipase A2 were not correlated with concomitant variations in the sera. Urinary lipid peroxides were directly correlated with the degree of liver morphological alterations and inversely with circulating GSH. Urinary outputs of lipid peroxides, phospholipase A2 and N-acetyl-glucosaminidase were correlated with each other. These results suggest that there is an imbalance in the oxidative-antioxidant hepatic system in experimental extrahepatic cholestasis. The reduced bioavailability of blood GSH may alter the oxidative equilibrium in other organs, such as the kidney, triggering and favoring the lipoperoxidative cascade.