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

BRAINS from patients with Alzheimer's disease contain diffuse and senile am yloid plaques. Using an experimental model, we have addressed the issue whe ther diffuse plaques of amyloid persist, develop with time, or both, in rat s injected with human beta-amyloid-(1-42)-peptide for 3 and 12 months after brain ischemia, Rats receiving beta-amyloid peptide for 3 months after bra in ischemia demonstrated widespread diffuse amyloid plaques in hippocampus and cerebral cortex. Neuronal, glial, ependymal, endothelial and pericyte c ell bodies were observed filled with beta-amyloid peptide. No staining was observed in control brains. In the group alive 1 year no deposition of huma n beta-amyloid peptide was observed. too. Direct evidence that diffuse amyl oid plaques can disappear in the brain is thus provided for the first time. (C) 1999 Lippincott Williams & Wilkins.