Abstract
Hepatocyte structural and functional integrity was characterised in rat and human short term monolayer cultures following isolation by a versatile biopsy perfusion technique. A cryopreservation scheme was developed for rat hepatocytes which were established in subsequent monolayer culture. Cytochrome P450 activity did not appear to be inhibited following cryogenic storage, and survival of human hepatocytes following cryopreservation was broadly similar to that of rat hepatocytes. This is particularly encouraging in relation to maximising the use of available human liver tissue. It may allow establishment of a bank of cryopreserved human hepatocytes, taken from numerous individuals, to be used in short term cytotoxicity assays. Cytotoxicity and perturbation of hepatocyte function involving measurement of a number of biochemical parameters was investigated following exposure to six chemicals (unknown at time of analysis). In general results were in agreement with reported in vivo data. This study highlights the potential use of hepatocyte culture systems for investigation of specific cytotoxic events despite the well documented changes in cytochrome P450 activity. The potential incorporation of human tissue into such systems is also emphasised since human cytochrome P450 activity seems much more stable in culture. Comparative analysis of xenobiotic metabolism and cytotoxicity data between cells isolated from laboratory animals and humans should allow a more critical evaluation of in vivo toxicological studies in laboratory animals. The use of human hepatocyte cultures should also put risk assessment in vivo on a more scientific basis.