Monooxygenation, conjugation and other functions in cryopreserved rat liver slices until 24 h after thawing

For the extensive use of precision-cut liver slices (particularly of human origin) for toxicological investigations successful cryopreservation is nec essary. But so far, survival of thawed slices was limited to few hours. Thi s was now overcome by modification of previous procedures. The concentratio n of DMSO as a cryoprotectant was enhanced to 30%, and washing steps after rapid thawing were omitted. The slices were frozen in liquid nitrogen, thaw ed at 38 degreesC and incubated immediately in Williams medium E. Protein a nd potassium contents were stable until 24 h. Glutathione content, amountin g to nearly 50% of fresh slices, increased during incubation. High initial lactate dehydrogenase leakage dropped after medium change to less than half during 2-24 h. Testosterone hydroxylation and 7-ethoxycoumarin O-deethylat ion rates were similar to fresh slices, the latter reaction was inducible b y P-naphthoflavone within 24 h. Methylumbelliferone glucuronidation and p-n itrophenol glucuronidation and sulfation were well measurable and either ma intained or decreased by about 50% until 24 h. Altogether. the results are encouraging for further experiments to standardise cryopreservation conditi ons and to investigate the suitability of this cryopreservation protocol wi th human liver slices. (C) 2001 Elsevier Science Ireland Ltd. All lights re served.