Comparison of hepatocyte cultures and liver slices in in vitro toxicity testing

The aim of this study was to compare the in vitro toxicities of two hepatotoxins in hepatocyte cultures and in liver slices from both rats and dogs. Hepatocytes and liver slices were pre-incubated for 2 hours and then exposed to galactosamine or paracetamol, both of which mainly induce liver necrosis in vivo. Following exposure to the compounds for 20 hours, neutral red uptake (NRU [hepatocyte cultures only]), MTT reduction, and reduced glutathione (GSH), adenosine triphosphate (ATP) and protein content, were used to measure the toxicity induced. In general, galactosamine and paracetamol exposure caused comparable levels of toxicity in hepatocyte cultures and in liver slices. For galactosamine, no consistent differences were seen between hepatocyte cultures and liver slices. With paracetamol, the toxic effects were generally slightly more pronounced in hepatocyte cultures than in liver slices, and the preparations from dog liver were more sensitive than those from rat liver to paracetamol exposure. These results are in agreement with previously described species differences in vitro. NRU and GSH content were more sensitive and more consistent endpoints than MTT reduction, ATP content or protein content. Liver slices appeared to lose viability over the 20 hours in culture. Therefore, it can be concluded that liver slices should only be used in relatively short-term investigations.