MITOCHONDRIAL FUNCTION AFTER LIVER PRESERVATION IN HIGH OR LOW IONIC-STRENGTH SOLUTIONS: A COMPARISON BETWEEN UW-BASED AND SUCROSE-BASED (SBS) SOLUTION

In this study we evaluated mitochondrial function after liver cold storage and normothermic reperfusion. The preservation solutions were: modified University of Wisconsin (mod UW); sucrose-based solution (SBS). After cold preservation liver was reperfused for I hour in vitro with Krebs-Ringer buffer at 37 degrees C. Samples of tissue were taken for ATP determination. Mitochondrial respiratory parameters, succinate oxidase complex activity, mitochondrial H+- ATPase and intramitochondrial potassium concentration were assayed. It was shown, that brief (1h) cold storage and subsequent normothermic reperfusion revealed no difference in liver ATP content between mod UW and SBS groups but resulted in a gradual decrease of 50% after 24-hour storage and reperfusion. Mitochondrial potassium ion concentration increased by 40% after 1-hour cold storage in the mod UW as compared to control (P < 0.05) and SBS. After brief cold storage ADP and uncoupler-stimulated respiration increased by 120% in SBS group, unlike mod UW, when succinate was used as substrate, and was more pronounced after 24 h. Succinate oxidase complex activity did not change over either cold storage or warm reperfusion. Mitochondrial H+-ATPase activities in SBS and mod UW did not differ and both were inhibited after 24-hour cold storage. Our data demonstrate that low ionic strength preservation solution can substantially modulate mitochondrial energy turnover due to substrate oxidation increase. Many of the changes in mitochondrial function follow brief exposure to low temperatures.