The Effects of Ethanol on Embryonic Chick Brain Mitotic Activity: A Model for Fetal Alcohol Syndrome

Abstract

Fetal Alcohol Syndrome (FAS) results from infrequent, high levels of ethanol consumption by the pregnant mother, and leads to microcephaly, growth and mental retardation, and facial disfiguration in offspring. The chick has been chosen as a model in FAS research in brain development because of the homology of the avian chorioallantoic membrane and mammalian placenta. In order to study the effects of ethanol on brain mitotic activity, a possible cause of microcephaly, ethanol's effect on tritiated thymidine incorporation into brain DNA was determined in these studies. Although measurements of brain weights support the conclusion that ethanol consumption leads to microcephaly, high brain weight/ body weight ratios suggest that overall growth inhibition may have more of a causal role in brain size. In addition, DNA percent composition and scintillation studies suggest that lack of brain mitotic activity is not the cause of microcephaly.