VIABILITY, ATTACHMENT EFFICIENCY, AND XENOBIOTIC METABOLIZING ENZYME ACTIVITIES ARE WELL MAINTAINED IN EDTA ISOLATED RAT LIVER PARENCHYMAL CELLS AFTER HYPOTHERMIC PRESERVATION FOR UP TO 3 DAYS IN UNIVERSITY OF WISCONSIN SOLUTION

Rat liver parenchymal cells were isolated by EDTA perfusion and were subsequently purified by Percoll centrifugation. The freshly isolated liver cells had a mean viability of 95% as judged by trypan blue exclusion. Isolated liver parenchymal cells were then stored at 0°C for up to 1 wk in University of Wisconsin solution (UW). During this hypothermic preservation, the viability was only slightly reduced to 92% after 1 d and to 85% after 3 d at 0°C. Thereafter, the viability decreased rapidly. After cold storage for up to 3 d, it was possible to use the parenchymal liver cells either in short-term suspension or in cell culture. The attachment efficiency in cell culture was the same for freshly isolated liver cells (84%) and after 2 d cold preservation (81%). The cytochrome P450 content and the enzyme activities of soluble expoxide hydrolase, UDP-glucuronosyl transferase, phenol sulfotransferase, and glutathione S-transferase were not significantly different between freshly isolated cells and cells after 3 d of hypothermic preservation. Furthermore, freshly isolated and intact liver cells stored for 3 d were used in the cell-mediated Salmonella mutagenicity test as a metabolizing system. Both fresh and stored liver parenchymal cells metabolized benzo(a)pyrene, 2-aminoanthracene, and cyclophosphamide to their ultimate mutagens. Thus, it was clearly demonstrated that EDTA-isolated liver parenchymal cells retain their xenobiotic metabolizing capacity after short-term hypothermic preservation for up to several days and, therefore, may help to maximize the usefulness of rarely available liver parenchymal cells such as those from humans and help to reduce the number of experimental animals required for pharmacological and toxicologicalin vitro investigations.