The effect of trichloroethylene on gene expression in mouse liver

Trichloroethylene (TCE) is a widely used industrial chemical, and a common environmental contaminant. It is a well-known carcinogen in rodents and a probable carcinogen in humans. Studies utilizing panels of mouse inbred strains afford a unique opportunity to understand both metabolic and genetic basis for differences in responses to TCE. We tested the hypothesis that individual and liver-specific toxic effects of TCE are genetically controlled and that the mechanisms of toxicity and susceptibility can be uncovered by exploring responses to TCE using a diverse panel of inbred mouse strains. TCE (2100 mg/kg) or corn oil vehicle were administered by gavage to 6-8 wk old male mice of 15 mouse strains. Serum and liver were collected at 2, 8, and 24 hr post dosing and were analyzed for TCE metabolites, hepatocellular injury and gene expression of liver. TCE metabolism, as evident from the levels of individual oxidative and conjugative metabolites, varied considerably between strains. TCE treatment-specific effect on the liver transcriptome was strongly dependent on the individual’s genetic background. PPAR-mediated molecular networks, consisting of the metabolism genes known to be induced by TCE, represent some of the most pronounced molecular effects of TCE treatment in mouse liver that are dependent on the individual’s genetic background. Conversely, cell death, liver necrosis, and immune mediated response pathways which are affected by TCE treatment in liver are largely genetic background-independent. These studies provide better understanding of the mechanisms of TCE-induced toxicity anchored on metabolism and genotype-phenotype correlations that may define susceptibility or resistance. 16 mouse strains were studied, vehicle control and mice treated by gavage with 2100 mg/kg Trichloroethylene and sacrificed 24 hrs after dosing