Bioaccumulation of water soluble aluminium chloride in the hippocampus after transdermal uptake in mice

Normally, only very small amounts of ingested aluminium are absorbed and accumulated. Despite the percutaneous absorption of many drugs and chemicals, the skin has not been considered as a possible site at which aluminium could enter the body. Application of low aqueous concentrations of aluminium chloride (A1C1(3), 6H20) (0.025-0.1 micrograms/cm2) to healthy shaved Swiss mouse skin for 130 days led to a significant increase in urine, serum and whole brain aluminium, especially in the hippocampus, compared to control animals. This percutaneous uptake and accumulation of aluminium in the brain was greater than that caused by dietary exposure to 2.3 micrograms per day in feed and water. In vitro studies demonstrated the passage of aluminium through viable mouse skin. This study shows for the first time that aluminium is absorbed through the skin of mice in vivo and this contributes to a greater body burden than does oral uptake.