Histological and histochemical changes of the placenta in fetal alcohol syndrome due to maternal administration of acute doses of ethanol in the mouse.

In both clinical and experimental research on the fetal alcohol syndrome (FAS) the possible involvement of the placenta has not been considered. In an attempt to investigate the effects of alcohol on the placenta, single doses of 0.02 ml and 0.03 ml/g body weight of freshly prepared solutions (25%, v/v) of absolute alcohol in saline were administered to MF1 mice on day 8 of gestation. Controls were saline treated or/and pair fed and pair watered. Fetuses and placentas were collected on day 18, weighed individually, observed for malformations and fixed. Paraffin sections of placentas of control and of fetuses with FAS were stained with hematoxylin and eosin, Best's carmine and PAS with and without diastase (saliva). The experimental fetuses and placentas were lighter in weight than the controls. The decidua basalis of placentas of FAS cases were occasionally vacuolated and infiltrated by lymphocytes. The glycogen and mucopolysaccharide content in the basal zone was reduced. In most situations the glycogen cells had degenerated and were replaced by an acidophilic mass. The cytoarchitecture of the labyrinthine zone had been altered. Large cysts filled most parts of the placenta; besides fibrinoid accumulation, extensive vacuolisation was also clearly visible. The overall width of this zone and arborisation of fetal vasculature were also reduced. The consistent association of these placental abnormalities with FAS in this mouse model is suggestive of placental mechanisms in FAS.