Renal effects of experimental obstructive jaundice: Morphological and functional assessment

Background The pathophysiology of renal impairments occurring in obstructiv e jaundice has been extensively studied, but the underlying mechanism of th ese derangements remains unclear. The aim of the present study was to inves tigate the time-related morphological and functional changes occurring in t he kidneys of rats undergoing obstructive jaundice. Methods. Histological examination, renal function assessment and determinat ion of (Na + K)-ATPase activity were performed in the kidneys of rats 7, 14 , and 21 days following bile duct ligation (BDL) or sham operation (sham). Results. Glomerular filtration rate was unaffected by BDL throughout the pe riod of the study. Tubular effects occurred at days 7 and 14, being more ma rked at day 7, and consisted of an increase of about twice in the fractiona l excretion of sodium and chloride, paralleled by a decreased proximal and distal tubular reabsorption of sodium of about 50 and 40%, respectively. Na triuresis was consistent with augmentation of osmolar clearance but it was not associated with changes in the activity of renal (Na+ + K+)-ATPase. The ability to dilute urine was impaired at days 14 and 21 after BDL. Addition ally, these effects were accompanied by decreased tubulointerstitial fibros is and vasodilation of inner medullary capillaries. At day 21, the paramete rs of tubular function in BDL and sham groups were not significantly differ ent. Conclusions. These data support the view that raised natriuresis taking pla ce in the initial 2 weeks following BDL is due mainly to tubular effects. T he contribution of hemodynamic, paracrine and humoral mediators is discusse d. (C) 1999 IMSS. published by Elsevier Science Inc.