TI: Cryopreservation of rat precision-cut liver slices
by ultrarapid freezing: influence on phase I and II metabolism and on cell
viability upon incubation for 24 hours.
AU: Vanhulle,-V-P; Martiat,-G-A; Verbeeck,-R-K; Horsmans,-Y;
Calderon,-P-B; Eeckhoudt,-S-L; Taper,-H-S; Delzenne,-N
AD: Unit of Pharmacokinetics, Metabolism, Nutrition and Toxicology,
Universite Catholique de Louvain, Brussels, Belgium.
SO: Life-Sci. 2001 Apr 13; 68(21): 2391-403
JN: Life-sciences
PY: 2001
AB: Several cryopreservation methods for precision-cut rat liver
slices (PCLS) have been proposed, allowing a short-term (a few hours) maintainance
of viability and functionality upon thawing. The aim of the present study
was to test the metabolic capacity of PCLS cryopreserved by an ultrarapid
method. The biotransformation of paracetamol to its glucuronide and sulfate
conjugates and of midazolam to its hydroxylated metabolites was studied
in thawed PCLS incubated for 24 hours at 37 degrees C in Williams' medium
E. In addition, protein levels of the key enzymes involved in these metabolic
reactions, i.e. UGT1A1, ST1A1, CYP2E1 and CYP3A2 were determinated. In
addition, biological markers of cell function (ATP and glycogen levels)
and toxicity (LDH leakage in the medium) were also measured. Compared to
controls (non cryopreserved PCLS), CYP3A2 activity and content and CYP2E1
content were maintained at the same level all along the incubation, whereas
paracetamol glucuronidation and sulfation dropped to 24 and 21% of the
control value, respectively, immediately after thawing. Freezing-thawing
conditions also modified cell functionality, leading to a lower intracellular
ATP and glycogen content, and an increase in cell lysis, as shown by LDH
released in the medium. The results of this study suggest that cryopreserved
PCLS are able to maintain some phase I activities for 24 hours after thawing
whereas some phase II metabolic capacities are not maintained.