DEVELOPMENTAL TOXICITY OF TRICHLOROETHYLENE, TETRACHLOROETHYLENE AND 4 OF THEIR METABOLITES IN RAT WHOLE-EMBRYO CULTURE

The embryotoxicity of trichloroethylene (TRI), tetrachloroethylene (PE R), and of four of their oxidative metabolites i.e. trichloroacetic ac id, dichloroacetic acid, chloral hydrate, and trichloroacetyl chloride , was studied in vitro, using the rat whole embryo culture system. Emb ryos from Sprague-Dawley rats were explanted on gestational day 10 (pl ug day = day 0) and cultured for 46 h in the presence of the test chem ical. All of the tested chemicals produced concentration-dependent dec reases in growth and differentiation and increases in the incidence of morphologically abnormal embryos. TRI and PER produced qualitatively similar patterns of abnormalities, while TRI and/or PER metabolites, e ach elicited clearly distinguishable dysmorphogenic profiles. The pres ence of hepatic microsomal fractions in the culture medium produced ma rked decreases in TRI- and PER-induced embryotoxic effects, including mortality, severity of malformations, and delayed growth and different iation.