Evaluation of cultured, precision-cut rat liver slices as a model to study drug-induced liver apoptosis

The precision-cut liver slice culture model has been used widely to investigate drug metabolism and drug-induced necrosis. However, apoptosis, a key mediator of liver toxicity remains to be studied in this model. We evaluated apoptosis induced by thioacetamide (TAA) in rat liver slices, and in livers taken from TAA-treated rats as a control. Rat liver slices were treated with 50, 75 and 100 mM of TAA for 15 h. Histopathological examination of the liver slices revealed specific centrilobular localization of apoptotic hepatocytes at 75 mM but randomly distributed at 100 mM. Apoptosis in centrilobular hepatocytes was confirmed by appearance of cleavage products of caspase-3 and DNA fragmentation studied by TUNEL method. A concentration-dependent release of cytochrome c was observed in the slices, suggesting a role for mitochondria in the apoptosis triggered by TAA. The in vitro results were compared to the data obtained in male Sprague-Dawley rats given a single ip injection of 40 mg/kg TAA and sacrificed 1, 2, 3 and 6 h after dosing. Histopathological analyses showed specific centrilobular localization of apoptosis after 6 h treatment. Caspase-3 activation, DNA fragmentation and cytochrome c release were also observed in the liver of rats treated with TAA. Overall these data indicated that precision-cut liver slices provide a valuable in vitro system to study drug-induced liver apoptosis.