Evaluation of hypertonic citrate flushing solution for kidney preservation using the isolated perfused rat kidney

The isolated perfused rat kidney has been used to study the effects of cold ischaemia during ice storage. Tissue adenine nucleotide levels in freeze-clamped kidneys were closely correlated with their function after circulation had been reestablished in the perfusion circuit. The ATP content was depleted to a greater extent than total adenine nucleotide after 8 hr of cold ischaemia but both were considerably diminished after 24 hr. The model was also used to compare four solutions which are available clinically for preliminary flushing of organs in the ice storage preservation technique. The results indicated that for periods of 8 and 24 hr of cold ischaemia, renal function and adenine nucleotide content were significantly better maintained with a solution based on hyperosmolar citrate than with Collins, Sacks, or Perfudex solutions. This study confirmed recent observations of the clinical efficacy of citrate solution, while demonstrating how the isolated perfused rat kidney could be used for rapid screening of modifications in preservation techniques.