Phosphorus-31 nuclear magnetic resonance of isolated rat liver during hypothermic ischemia and subsequent normothermic perfusion

Abstract

The effects of prolonged hypothermic ischemia and subsequent normothermic perfusion on the energetic metabolism and intracellular pH (pH in) of isolated rat livers were studied by phosphorus-31 nuclear magnetic resonance spectroscopy. Nucleoside triphosphate (NTP) depletion and intracellular pH were studied within an 18-h-storage phase, by using the following preservation media: Eurocollins (EC), UW Lactobionate (UW) and Bretschneider's solution (HTK). Values obtained after 8-h ischemia were chosen to estimate the performance of the various media: NTP levels were 37 ± 7%, 10 ± 5% and 0% of control levels, respectively, in livers stored in UW, HTK and EC solutions. pH in reached values of 7.15 ± 0.10 in UW and HTK, and 6.96 ± 0.10 in EC-stored livers. Ischemic damage was assessed by reperfusing the stored organ with Krebs medium: NTP recovery was around 70 ± 20% for the three solutions used. Recovery of pH in was near the control value (7.23 ± 0.08), except for EC solution (7.05 ± 0.20). The main results are that (i) the rates of NTP and pH in decrease are strongly dependent on the nature of the preservation solution, whereas (ii) NTP recovery is not significantly different during post-ischemic reperfusion. With regard to animal survival, UW solution is at present considered largely superior to EC medium for liver preservation. Thus, our data suggest that the rates of NTP depletion and pH in fall during cold preservation could be both considered as better indicators assessing liver injury than the post-ischemic NTP recovery.