A simple method for cryopreservation of liver slices from man and other species

The cryopreservation of liver slices permits optimal use of large livers and provides for the availability of the slices at any desired time. Moreover, it allows one to study liver slices from various species in the same experiment. We studied the effect of cryopreservation on the viability and metabolic activity of liver slices from rat, monkey, dog, hamster, minipig, rabbit and human. Precision-cut liver slices were prepared using a Krumdieck tissue slicer. Human donor liver tissue was obtained and studied at the Dept. Pharmakinetics and Drug Delivery at the University of Groningen. Animal livers were from control animals in toxicity studies at Solvay. Slices were cryopreserved by incubation in 12% dimethylsulphoxide (DMSO) in Williams’ medium E for 30 min on ice, followed by fast freezing into liquid nitrogen. Viability was determined by measuring alanine aminotransferase activity retention in the slices, and by measuring urea synthesis, and phase I and II metabolic activity by testosterone metabolism. The viability of rat, monkey, dog and human liver slices after thawing was retained close to fresh values during 3 h of incubation (80-100% of fresh values). In addition, no significant differences were detected in metabolite patterns of the three drugs tested between fresh and cryopreserved liver slices. These results show that cryopreservation of liver slices from various species by the same simple cryopreservation procedure can maintain viability and metabolic competence as measured in fresh slices. Therefore, cryopreserved liver slices from various species can be used to compare the metabolite patterns of xenobiotica such as candidate drugs. Efficient use of tissue can be accomplished by cryopreserving liver slices, thus reducing the use of experimental animals. In addition, optimization of the choice of animal species for toxicity testing of drugs in development allows reduction of experimental animal use and facilitates a safer first administration to man.