A teratogenicity study of Phloxine B in ICR mice.

Pregnant Jcl:ICR mice were given Phloxine B in the diet at concentrations of 0, 1, 3 and 5% from the morning of day 6 through day 16 of gestation. The mice were killed on day 18 and foetuses were examined for external, visceral and skeletal anomalies. A significant decrease in body-weight gain was observed in all of the treated groups. Among the dams in the high-dose group, two maternal deaths, one abortion and a significant increase in liver weight were observed. A dose-related incidence of splitting of the cervical vertebral arches (nos 3-6) was noted in all of the treated groups, but this anomaly was not found in the controls. The total incidence of skeletal anomalies was also dose related and was significantly increased at the 3 and 5% dose levels. It was concluded that Phloxine B was teratogenic in mice at dietary levels of 3 and 5%, levels which resulted in maternal toxicity, and that a finding suggesting a teratogenic effect (split cervical arches) was also noted at the 1% dose level.