Use of cryopreserved animal and human hepatocytes for cytotoxicity studies

To evaluate the potential use of cryopreserved hepatocytes for toxicological studies, rat, dog and human hepatocytes were frozen in Leibovitz medium containing 20% foetal calf serum and various concentrations of dimethylsulphoxide and stored in liquid nitrogen. 50% or more of the hepatocytes that attached and survived immediately after isolation still possessed these properties after freezing/thawing. Thawed hepatocytes from the three species showed only a slight reduction in their ability to metabolize phenacetin or to conjugate paracetamol with glucuronic acid. Sensitivity to the toxic effects of erythromycin was not affected by the MTT and neutral red assays. Similar observations were made with rat hepatocytes for five other toxic agents-chloramphenicol, chlorpromazine, acrylamide, chloroquine sulphate and p-chloromercuribenzoic acid. These results suggest that, after cryopreservation, isolated hepatocytes represent a suitable model for drug metabolism and toxicity screening studies.