Aluminum, restraint stress and aging: Behavioral effects in rats after 1 and 2 years of aluminum exposure

Both aluminum (Al) and aging have been associated with neurobehavioral changes in mammals. In this study, the long-lasting neurobehavioral effects of prenatal restraint stress and oral Al exposure from conception to sacrifice were assessed in adult (1 year) and old (2 years) rats. Pregnant females were orally exposed to 0, 50, and 100 mg Al/kg/day. Each Al-exposed group was divided into two subgroups. One of this was subjected to restraint stress (2 h/day on gestation days 6–20). The offspring of the treated females were maintained with the same Al treatment until sacrifice at 1 or 2 years of age. Activity in an open-field and learning in a water maze were evaluated. Although no significant differences were observed in motor activity, a biphasic effect of Al on learning could be observed. Thus, exposure to 100 mg Al/kg decreased performance of the task in both adult and old rats when compared to animals exposed to 50 mg Al/kg. An age-related effect on water maze performance, as well as an accumulation of Al in brain of rats exposed to 100 mg Al/kg at 2 years of age was found. Interestingly, while prenatal restraint stress did not modify behavioral parameters, Al accumulation was prevented by prenatal restraint.