TIME-RELATED CHANGES OF COLD-STORED RAT-LIVER IN UNIVERSITY-OF-WISCONSIN SOLUTION - EFFECT OF URSODEOXYCHOLATE

Livers of Wistar rats were stored between 0 and 36 hrs. in the Univers ity of Wisconsin preservation liquid in order to determine time-relate d biochemical and morphological hepatic changes. Ursodeoxycholate (100 mu M) was also added in the medium to test the hepatoprotective prope rties of the bile salt. Biochemical assays were performed on hepatic m icrosomes, plasma and biliary canalicular membranes. Protein and lipid composition of the microsomal and base-lateral plasma membranes remai ned stable. Protein and cholesterol content of the biliary canalicular membranes decreased, phospholipid/cholesterol ratio increased between 0 and 36 hrs.; it resulted in a leak of 5'-nucleotidase and leucine a mino peptidase activity of these biliary canalicular membranes, especi ally up to 12 hrs. Between 0 and 36 hrs., the lipid and protein conten t remained stable in the plasma membranes, as well as both tested enzy matic activities. Observations under electron microscopy showed altera tions and underlined fragility of the bile canaliculi, particularly af ter 24 hrs. preservation. Ultrastructure of sinusoidal membranes showe d damaged microvilli. Endoplasmic reticulum remained unchanged, in rel ation to the stability of the microsomal lipidic, proteic content and hydroxymethylglutaryl-coenzyme A reductase activity, except the decrea sed protein content after preservation for 36 hrs without ursodeoxycho late. Ursodeoxycholate by itself did not protect against the described disturbances.