Inhibition of lipopolysaccharide-induced liver injury in rats treated with a hepatic drug-metabolizing enzyme inducer p,p′-DDT

Hepatocellular hypertrophy in association with drug-metabolizing enzyme induction is considered to be an adaptive change associated with drug metabolism. To improve our understanding of liver hypertrophy, we determined the effect of a single ip injection of either lipopolysaccharide (LPS) or vehicle in male F344 rats with hepatocellular hypertrophy induced by oral delivery of p,p′-DDT for 2 weeks. The rats were sacrificed 3 h or 24 h after LPS or vehicle injection. LPS induced a focal hepatocellular necrosis in rats fed the control diet. When rats pre-treated with p,p′-DDT were injected with LPS, necrotic foci surrounded by ballooned hepatocytes were observed in the liver. The change was consistent with reduced LPS-mediated increases in plasma hepatic biomarkers, neutrophil influx, and apoptosis, and also associated with hepatic mRNA levels of TNF-α, CYPs, and NOS2. By contrast, when combined with p,p′-DDT and LPS, faint hepatocellular fatty change was extended, together with a synergistic increase in total blood cholesterol. These results suggest that hepatocytes exposed to p,p′-DDT are protected from the cell-lethal toxic effects of an exogenous stimulus, resulting in cell ballooning rather than necrosis in association with reduced inflammation and apoptosis, but compromised by an adverse effect on lipid metabolism.