Effects of maternal age on teratogenicity of di-n-butyltin diacetate in rats

The present study was designed to assess changes in the teratogenic potency of di-n-butyltin diacetate (DBTA) with increasing maternal age in rats. Pr egnant Wistar rats of 3, 7.5 or 12 months were treated orally with DBTA at 0, 7.5. 10, 15 or 22 mg/kg on day 8 of gestation. Cesarean sections were pe rformed on day 20 of gestation. Maternal age had greater impact on litter s ize in the 7.5- and 12-month dams than the 3-month dams. The death of most of the fetuses of the 12-month dams made it difficult to evaluate the terat ogenic potency of DBTA. In 3-month groups, fetuses with external malformati on, such as cleft mandible, cleft lower lip, ankyloglossia and/or schistogl ossia, which are malformations typical of DBTA, were observed at 15 and 22 mg/kg, while similar malformations were observed in 7.5-month groups at dos es of 10 mg/kg and above. At 15 and 22 mg/kg, the incidences of these malfo rmations in 7.5-month groups were similar to these from 3-month groups. In our previous studies, however, single DBTA-treatment at 10 mg/kg on day 8 o f gestation has not produced such malformations from 3-month dams. The resu lts suggest that the teratogenic potency of DBTA in 7.5-month dams may be g reater than in 3-month dams. (C) 2001 Elsevier Science Ireland Ltd. All rig hts reserved.