Further examination of the selective toxicity of CCl4 in rat liver slices.

Lipid peroxidation and loss of enzymes located predominantly in either periportal or centrilobular hepatocytes were investigated in precision-cut liver slices from male Sprague-Dawley rats. Pretreatment of animals with 80 mg/kg phenobarbital for the site-specific enzyme studies enhanced and accelerated CCl4 toxicity in slices resulting from increased radical formation. Liver slices were exposed to 0.57 mM CCl4 by vaporization using a roller incubation system at 37 degrees C for a total of 9 hr. Conjugated diene formation, an index of lipid peroxidation, was detected 15 min following CCl4 administration and increased over time. Loss of cytochrome P450 occurred in a time-dependent manner relative to controls where levels in treated slices were 42% of controls at 9 hr. A 48-hr fast prior to termination increased intracellular K+ leakage relative to that present in slices from fed animals. Significant leakage of glucose-6-phosphate dehydrogenase and beta-glucuronidase from centrilobular hepatocytes occurred 9 hr following CCl4 administration. The content of the periportal enzymes (lactate dehydrogenase and sorbitol dehydrogenase) was unchanged in the same slices over the duration of the experiment. Reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide, a mitochondrial selective dye and indicator of viability, was significantly lower in treated slices from phenobarbital-treated animals at 9 hr relative to controls. These studies demonstrate that precision-cut slices are an ideal in vitro system for mechanistic studies and the investigation of site-specific toxicants since the integral architecture of the liver and cellular identity are maintained.