Ischemic rats as a model in the study of the neurobiological role of human β-amyloid peptide. Time-dependent disappearing diffuse amyloid plaques in brain

Brains from patients with Alzheimerʼs disease contain diffuse and senile amyloid plaques. Using an experimental model, we have addressed the issue whether diffuse plaques of amyloid persist, develop with time, or both, in rats injected with human β-amyloid-(1–42)-peptide for 3 and 12 months after brain ischemia. Rats receiving β-amyloid peptide for 3 months after brain ischemia demonstrated widespread diffuse amyloid plaques in hippocampus and cerebral cortex. Neuronal, glial, ependymal, endothelial and pericyte cell bodies were observed filled with β-amyloid peptide. No staining was observed in control brains. In the group alive 1 year no deposition of human β-amyloid peptide was observed. too. Direct evidence that diffuse amyloid plaques can disappear in the brain is thus provided for the first time.