Sensitivities of gel entrapped hepatocytes in hollow fibers to hepatotoxic drug

The aim of this study was to determine the feasibility of detecting hepatotoxicity using gel entrapped hepatocytes in simple hollow fibers. Four typical hepatotoxic drugs were tested for hepatotoxicity in gel entrapped hepatocyte as opposed to hepatocyte monolayer, a hepatocyte system extensively used for hepatotoxicity studies in vitro. Hepatotoxicity or cell damage was assessed by the methyl tetrazolium (MTT) assay, liver-specific functions and the intracellular glutathione (GSH) content. After exposure to acetaminophen, significant cell damage of gel entrapped hepatocytes was detected at 48 h while hepatocyte monolayer was not so sensitive except for albumin synthesis and this difference between two hepatocyte systems was similar on hepatotoxic response to antituberculosis drugs including rifampicin and isoniazid. At low concentrations of either rifampicin or isoniazid, time-dependent hepatotoxicity was only evidenced in gel entrapped hepatocytes after treatment and no cell damage occurred in hepatocyte monolayer at an incubation time as long as 96 h. Interestingly, hepatotoxicities of acetaminophen, isoniazid and rifampicin are all reportedly relevant to drug metabolisms of cytochrome P450. For sodium salicylate whose hepatotoxicity is unassociated to P450 activities, more significant reductions on cell viability and albumin synthesis at 5 mM than those at 1 mM apparently illustrated the concentration-dependent hepatotoxicities of gel entrapped hepatocytes as well as hepatocyte monolayer. It is highly suggested that gel entrapped hepatocyte are more sensitive in evaluation of hepatotoxicities than hepatocyte monolayer if this hepatotoxicity is related to drug metabolism. Thus, gel entrapment culture of hepatocytes with simple hollow fibers could be recommended for hepatotoxicity studies in vitro.