Aluminium incorporation into the brain of rat fetuses and sucklings

Aluminium is highly neurotoxic and inhibits prenatal and postnatal development of the brain in humans and experimental animals. However, the incorporation of aluminium into the brain of fetuses and sucklings during gestation and lactation has not been well clarified because aluminium lacks a suitable isotope for a tracer experiment. In this study, we used 26Al (a radioisotope of aluminium with a half-life of 716,000 years) as a tracer, and measured 26Al incorporation into the brain of rat fetuses and sucklings by using accelerator mass spectrometry. 26Al (26AlCl3) was subcutaneously injected into pregnant rats and lactating rats. By day 21 of gestation, considerable amounts of the 26Al injected into the pregnant rats had been transferred to the brain and nuclear fraction (brain cell nuclei) of the rat fetuses. From day 5 to day 20 postpartum, the amounts of 26Al measured in the brain of suckling rats increased significantly. On day 20 postpartum, 26Al was found in the nuclear fraction isolated from the brain of suckling rats. It is concluded that 26Al subcutaneously injected into pregnant rats and/or lactating rats was incorporated into the brain and nuclear fraction (brain cell nuclei) of fetuses and sucklings through the transplacental passage and/or maternal milk.