Cytosine arabinoside-induced transplacental dysgenetic hydrocephalus in mice

Pregnant mice were injected with 30 mg of cytosine arabinoside/kg body weight on 13‐1/3 and 14 days of gestation. Within six hours after the first injection, pyknotic nuclei and nuclear debris were found at the matrix layer surrounding the lateral ventricles of the embryonic brain. Autoradiographic studies using tritiated thymidine revealed that most of the matrix cells exposed to cytosine arabinoside during DNA synthesis were killed by this dose of the drug. Twenty‐four hours after the second injection, most of the matrix cells had disappeared. When experimental animals were examined after birth, they showed marked dilatation of the lateral ventricles. The dilatation of the lateral ventricles was more pronounced in the parieto‐occipital region. The young showed rapid enlargement of the cranial vault and subsequently died by 35 days of age.