Melatonin protects against renal oxidative stress after obstructive jaundice in rats

The goals of this study were to analyze the renal oxidative status in exper imental biliary obstruction and to evaluate the impact of melatonin on rena l oxidative stress. Cholestasis was done by double ligature and section of the extra-hepatic biliary duct. Melatonin was injected i.p. (500 mug/kg/day ). Malondialdehyde, reduced glutathione. catalase, superoxide dismutase, gl utathione reductase, glutathione peroxidase and glutathione transferase wer e determined in the renal tissue. After biliary obstruction, an increase in malondialdehyde (P < 0.0001) and a fall in reduced glutathione (P < 0.0001 ) were seen. Moreover, the scavenger enzyme activity had significantly dimi nished. After melatonin administration, the malondialdehyde fell significan tly (P < 0.0001), whereas reduced glutathione showed an important increase (P < 0.0001) compared with the ligated bile duct group. Experimental bile d uct obstruction was associated to an increase of renal oxidative stress. Tr eatment with melatonin decreased the renal lipid peroxidation, and both the reduced glutathione as well as the scavenger enzyme activity recovered. (C ) 2001 Published by Elsevier Science B.V.