Alterations in deoxyribonucleic acid and proteins in cerebral tissues from fetuses subject to alcohol in utero.

Critical period for intra-uterine growth retardation (IUGR), and biochemical parameters for tissue growth were studied in an animal model of Fetal Alcohol Syndrome (FAS) in rats. Our research used 40 animals, fed Lieber and DeCarli liquid diets, distributed into 4 groups: C, or control--non-alcoholic--, ad libitum; E, or alcoholic, fed ad libitum; F, or alcoholic, pair fed to E; and P, non-alcoholic, pair fed to E and F. Fetuses of group E were exposed to ethanol during the organogenic period, while those from group F exposed only during the last stage of pregnancy. Blood alcohol levels were determined both at the end of 42 days before pregnancy, and on days 3, 7, 14 and 19 of gestation. The brain content of total DNA and proteins was measured, along with the cell size of fetal tissues. Non-parametric statistics were applied, considering the litter as unit, and 5% as the significant level. Prenatal ethanol exposure was associated with a cell size, total DNA, and cerebral protein content all significantly lower (p less than or equal to 0.05) than in non-alcoholic groups. These facts strongly suggest that the critical period for growth retardation associated with FAS may be situated at the end of pregnancy, when metabolic disturbances of the brain could also arise, while major external malformations are likely to be produced during organogenesis.