Frozen-sectioning yields similar results as traditional methods for fetal cephalic examination in the rat.

Background: An integral component of developmental toxicity studies is the evaluation of fetal anatomy, which consists of external, visceral, and skeletal examinations. The visceral examination includes an assessment of the fetal head which, in the rat, is typically completed after chemical fixation. Because chemical fixation requires approximately 7 days, a comprehensive visceral examination, including the head, of the fetal rodent cannot be completed at the time of cesarean section.

Developmental toxicity of 1,6-hexamethylene diisocyanate (HDI) in the Sprague-Dawley rat.

Background: 1,6-Hexamethylene diisocyanate (HDI), a widely used chemical in commercial polyurethane manufacture, has been shown to affect the respiratory tract of experimental animals. However, its potential to affect neonatal development, particularly after inhalation exposure, is less well described. The present study was conducted to assess the developmental toxicity of HDI.

A combined reproduction, neonatal development, and neurotoxicity study with 1,6-hexamethylene diisocyanate (HDI) in the rat.

1,6-Hexamethylene diisocyanate (HDI), a chemical widely used in commercial polyurethane products, was evaluated in a combined reproductive/developmental/neurotoxicity study. Sprague-Dawley rats (n = 120; 15 per sex/dose group) were administered via whole-body inhalation exposure either 0, 0.005, 0.

Large-scale double-staining of rat fetal skeletons using Alizarin Red S and alcian blue.

A critical component in the conduct of a prenatal developmental toxicity study is the evaluation of fetal skeletal development. As the developing rodent fetus is typically evaluated at gestation day 20, at a time when ossification of the skeleton is incomplete, a thorough assessment of skeletal development would include both ossified and cartilaginous structures. Current methods to double-stain the fetal skeleton using Alizarin Red S and Alcian Blue are typically described for small sample sizes or using time allotments for each processing step that are unsuitable for industry.