Trichloroethylene: A cardiac teratogen in developing chick embryos

Prior studies have evaluated the teratogenicity of TCE, a contaminant of drinking water. However, none specifically examined effects of TCE on cardiogene-sis. The purpose of this study was to determine if TCE is a cardiac teratogen in early embryogenesis in an avian model. Fertile White Leghorn chicken eggs were incubated under standard conditions. At stage 6,12,18, or 23, TCE, in concentrations of 5 to 25 μM (2 to 28 /μg/g body weight) was injected into the air space of the egg (vol = 0.03 ml). Mineral oil and saline served as control solutions. For this double-blinded study, solutions were coded and remained so until all observations were made and recorded. Embryonic hearts (n = 1055) were examined at stage 29, 34, or 44. Gross examination was performed, followed by microdissection. Cardiac malformations were found in 7.3% of TCE-treated hearts, compared to 2.3% of saline controls (p < 0.01), and 1.5% of mineral oil controls (p < 0.001). No significant difference in incidence of malformations was found when comparing saline and mineral oil controls. Cardiac defects include septal defects, cor biloculare, con-otruncal abnormalities, atrioventricular canal defects, and abnormal cardiac muscle. These data demonstrate that TCE is a cardiac teratogen in an avian model.