Concentrations of some essential elements in the brain of aluminum-exposed rats in relation to the age of exposure

This study evaluated the influence of age on the aluminum (Al) interaction with calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), copper (Cu) and zinc (Zn) in the brain of rats. Since both Al and aging have been associated with neurobehavioral deficits in mammals, the brain was chosen to assess that influence. Male young (21 day), adult (8 months), and old (16 months) rats were given 0, 50, and 100 mg/kg per day of aluminum administered as aluminum nitrate in drinking water for 6.5 months. During that period, citric acid (0, 355 and 710 mg/kg per day) was also added to the drinking water. After 6.5 months of Al exposure, Al, Ca, Mg, Fe, Mn, Cu and Zn concentrations were determined in brain tissue as well as in a number of cerebral regions: cortex, hippocampus, striatum, cerebellum, thalamus, olfactory bulb, and rachidical bulb. While no significant age-related differences were found for Ca concentrations in the seven cerebral regions analyzed, most Mg, Fe, Mn and Zn levels were significantly higher in young than in adult and old rats. In turn, Al concentrations were mostly higher in the cerebral regions of young rats than in the same regions of adult and old rats. In contrast, Cu levels were lower in most brain regions of old animals than in those of young rats. According to the results of the present study, the age-related changes in brain Al, Ca, Mg, Fe, Mn, Cu and Zn concentrations induced by Al and aging would not suggest any influence on Al-induced neurobehavioral deficits. (C) 1997 Elsevier Science Ireland Ltd.