Effects of trichloroethylene and its metabolite trichloroacetic acid on the expression of vimentin in the rat H9c2 cell line.

Trichloroethylene (TCE) and its metabolite trichloroacetic acid (TCAA) are environmental contaminants with specific toxicity for the embryonic heart. In an effort to identify the cellular pathways disrupted by TCE and TCAA during heart development, we investigated their effects on expression of vimentin, a marker of cardiac differentiation. Previous studies had shown that the level of vimentin transcript was inhibited in rat embryonic heart after maternal exposure to TCE via drinking water. In the same study, maternal exposure to TCAA produced the opposite effect, inducing an increased level of vimentin mRNA. In this study, we selected an in vitro system, the rat cardiac myoblast cell line H9c2, to further characterize the molecular mechanisms used by TCE and TCAA to disrupt normal heart development. In particular, we investigated the effects of both toxicants on vimentin, at both the RNA and protein levels, using dose-response and time course curves. Our experimental findings indicate that vimentin expression is affected by TCE and TCAA in H9c2 cells similarly as in vivo. The work is significant because it provides a suitable in vitro model for studies looking at toxicant effects on myocardiac cells, and it suggests that vimentin is a good marker of TCE exposure in the embryonic heart.