Trichloroethylene liver toxicity in mouse and rat: microarray analysis reveals species differences in gene expression

Area of Science:

• Environmental Science
• Toxicology
• Genomics

Background:

• Trichloroethylene (TCE) is an environmental organic solvent recognized as a carcinogen in animals, with suspected human carcinogenicity.
• TCE's carcinogenic effects vary by species, inducing liver cancer in mice and kidney cancer in rats.
• Understanding TCE's specific mode of action (MOA) is crucial for accurate human health risk assessment.

Purpose of the Study:

• To investigate the molecular mechanisms underlying TCE's carcinogenicity.
• To compare the species-specific gene expression changes induced by TCE in mice and rats.
• To identify dose- and time-dependent effects of TCE exposure on biological pathways.

Main Methods:

• Administration of TCE via oral gavage to mice and rats (single and 14-day daily exposure).
• Analysis of liver gene expression profiles using microarray technology.
• Identification of differentially expressed genes and affected biological pathways.

Main Results:

• Distinct transcriptional profiles were observed between mice and rats exposed to TCE.
• Species-specific and pulse-dose dependent alterations in biological pathways were identified.
• Inhibition of the TGF-beta pathway and activation of MAPK signaling were specific to mice with repeated TCE exposure.

Conclusions:

• Gene expression profiling reveals significant species-specific differences in TCE's biological activity.
• Understanding TCE's mode of action in animal models provides insights into potential human health effects.
• These findings contribute to a more refined assessment of TCE-related cancer risks in humans.