Formation of dichloroacetic acid by rat and mouse gut microflora, an in vitro study.

Metabolism of trichloroethylene (TRI) and its major metabolite, trichloroacetic acid (TCA), by gut content and gut microflora cultures was studied to gain an insight into the role of enterohepatic circulation in TRI metabolism. TRI and TCA were incubated anaerobically with rat and mouse cecal contents and TCA was additionally incubated anaerobically and aerobically with microflora cultures from mice. Although TRI was not metabolized by rat or mouse cecal contents. TCA was metabolized to dichloroacetic acid (DCA) by cecal contents. DCA formation in microflora cultures was dependent on initial TCA concentration, duration of incubation, and initial bacterial number. DCA was not observed in aerobic cultures exposed to TCA. These results suggest that strict anaerobic microorganisms of the gut may partly be responsible for dechlorination of TCA to DCA.