Congenital anomalies in mice induced by etretinate

We report on the experimental induction of anorectal malformations (ARM) an d other internal and external malformations in mouse fetuses induced by mat ernal administration of etretinate, a long-acting Vitamin A analogue. The t eratogen was administered to pregnant mice between the 7th and 10th gestati onal days (E7 and E10). The mice of the control group were given pure sesam e oil on E9. We examined survival rates, crown-rump length, and the inciden ce of internal and external malformations, with particular attention to ARM , in each group. All mice in the E8 group exhibited rectovesical fistula, h ydronephrosis, and spina bifida. All males and females in the E9 group give n 60 mg/kg of etretinate developed rectoprostatic urethral fistula and rect ocloacal fistula, respectively. The E10 group, given 60 mg/kg of etretinate displayed cleft palate (63.6%), forelimb malformation (68.2%), and a short club-shaped tail (100%). The fetuses had more severe types of ARM when etr etinate had been administered on an earlier gestational day. The E9 group i s a useful model for anorectal malformation, whereas the E8 group is a mode l for hydronephrosis and spina bifida.