Embryotoxic effects of di-2-ethylhexyl phthalate (DEHP) and di- n-butyl phthalate (DBP) in mice

Abstract

Two major compounds of PVC plasticizers, di-2-ethylhexyl phthalate (DEHP) and di- n-butyl phthalate (DBP), were mixed with food at levels of 0.05, 0.1, 0.2, 0.4, and 1.0 wt% and given to pregnant mice of ICR-JCL strain throughout gestation. Treatment with 0.2, 0.4, and 1.0% DEHP and 1.0% DBP resulted in decreased maternal weight gain and increased resorption rate. All of the implanted ova died in utero at 0.4 and 1.0% level of DEHP. The malformation rate in term fetuses increased at 0.2% level of DEHP and 1.0% level of DBP, the difference from the control group being at the borderline level of significance. The major malformations observed in the treated groups were neural tube defects (exencephaly and spina bifida), suggesting that the phthalic acid esters could interfere with the closure of neuropores in developing embryos. Treatment with the compounds caused intrauterine growth retardation and delayed ossification with an apparently dose-related response pattern. These results indicate that DEHP and DBP at a high dose level could be embryotoxic and possibly teratogenic mice. The maximum no effect level of the PAEs on mouse fetuses was 70 mg/kg/day, which is far higher than the estimated human current intake from the environment.