Resumo

Prenatal ethanol exposure is one of the main avoidable causes of birth defects, including developmental and behavioral dysfunctions. The minimum quantity of ethanol required to produce neurobiological damage is still unknown. Some animal models for prenatal ethanol exposure (PEE) can help us to clarify the different kinds of damage caused.Objective:In the present study we used an animal model to show the effects of different moderate ethanol doses on development and behavior of pups whose mothers were exposed to ethanol during gestation. A liquid diet administered orally was chosen for painless and stress-free exposure to ethanol.Method: We used 93 females and 31 male Lister hooded rats to obtain 44 litters that were divided into five different groups. During the gestational period, two groups of rats received a nutritionally balanced liquid diet with two different ethanol doses, 10% (A10, n=7) or 26% (A26, n=16) v/w. The same liquid diet without ethanol and with additional maltodextrin - in order to keep the diets isocaloric - was delivered to two control groups (C10, n=6 and C26, n=7). Dry food and water were delivered ad libitum to the chow group (n=8). The exposure period to the liquid diet started on gestational day 1 and was suspended on the day of parturition. The developmental tests (weight, righting reflex, negative geotaxis, grip strength, eye opening and incisor eruption) and behavioral tests (open field and elevated plus maze) were performed between the first postnatal day (PND 1) and PND 60. After 22 days of ethanol exposure, five female rats were sacrificed for blood ethanol levels (BEL).Results: Two-way ANOVA for repeated measures followed by Bonferroni post-hoc tests revealed that groups were not different in their body weight at birth. Ethanol-exposed groups showed a delay in incisor eruption (F(4,38)=3,80; p< 0,01) when compared with controls. A10, A26 and C10 groups showed delayed righting reflex development on PND 2-5 (F(4,38) = 4,56; p< 0,001), and weaker grip strength on PND 14 and 17 compared with control C26 and chow groups. Negative geotaxis was performed progressively faster by all groups from PND 7 to 10, but the chow group performed it faster on all PND (group x day, F(12,144)=2.22; p<0.02). Performance on the elevated plus maze test was analyzed with one-way ANOVA and revealed that ethanol group exposed to 26% v/w of ethanol showed a higher number of entries into open arms (F(4,38)=4,15; p< 0,01) and closed arms (F(4,38)=4,89; p< 0,01), spent more time in open arms (F(4,38)=10,11; p< 0,001) and had the highest number of risk assessment responses (F (4,38)=8,63; p< 0,001).Conclusion: The damage caused by ethanol intake during the gestational period can be different depending on some factors such as, ethanol intake dose. Nevertheless, even a moderate dose of ethanol intake during the gestational period can result in motor, maturational and behavioral deficits. Support: Wellcome Trust, FAURGS and CNPq