Effect of acetaldehyde on the neuroepithelium of early mouse embryos.

Female mice were injected intravenously with acetaldehyde on single (seventh, eighth or ninth), or on multiple (sixth to eighth, seventh to ninth) days, and examined on the tenth or twelfth day of gestation. Exposure to acetaldehyde on multiple days resulted in high incidence of embryonic resorptions. However, when females were injected on single days and examined on the tenth day, a high incidence of neural tube defects was encountered in surviving embryos. The neural tube anomalies were located at a number of sites along the neuraxis. When examined by scanning electron microscopy, the individual neuroepithelial cells in acetaldehyde-treated embryos exhibited a characteristic rounded-up appearance with small surface blebs and spiny processes. These characteristic cell surface features were seen in acetaldehyde-treated embryos at all stages of development examined. When additional females were examined on the twelfth day, a much lower incidence of open neural tube defects was observed. When embryos at this stage of development were examined in more detail by SEM, many had numerous subectodermal blebs along the dorsal mid-line, which were not initially apparent on gross inspection. The neuroepithelial morphology was also found to bae abnormal in embryos with no obvious external anomalies. The results confirm and elaborate on previous observations on the teratogenicity of acetaldehyde, stressing the ultrastructural changes that are induced in the cells of the neuroepithelium, and the possible relationship between the damage induced by this agent and certain features of the fetal alcohol syndrome.