Aluminum chloride does not facilitate deposition of human synthetic amyloid β1-42 peptide in the rat ventricular system of a short-term infusion model

Recent data have demonstrated that a 39-43 amino acid peptide called β-amyloid peptide (Aβ), which predominantly contains 42 residues (Aβ1-42), has a strong tendency to form insoluble aggregates and that the toxic effects of Aβ are based on its aggregation. In a previous study, we reported that infusion of 100 μg of human synthetic Aβ1-42 (sAβ1-42), which is a main component of diffuse plaques, into the lateral ventricle of the rat brain of a short-term infusion model resulted in almost complete disappearance of sAβ1-42 aggregates from the ventricles by 28 days. In addition, aluminum is considered a potential etiological factor in Alzheimer's disease (AD). Neurotoxicity from excess brain exposure to aluminum has been documented from both clinical observations and animal experiments, although a direct relationship between aluminum and AD has yet to be clearly established. We therefore investigated the effects of sAβ1-42 aggregates with aluminum chloride (AlCl₃) in the ventricular system of the rat brain of a short-term infusion model. At either 2 or 7 days following infusion, sAβ1-42 formed aggregates with AlCl₃ that spread throughout the entire ventricular system. However, sAβ1-42 aggregates with AlCl ₃ had almost disappeared from the ventricles by 28 days, resulting in similarities with respect to the time-course and the neuropathological changes observed in sAβ1-42 aggregation without AlCl₃. We herein report for the first time that considerable amounts of sAβ1-42 aggregates with AlCl₃ almost disappear from the rat ventricular system by 28 days post-infusion.