Long - term behavioral, histological, biochemical and hematological evaluations of amyloid beta - induced Alzheimer’s disease in rat

Alzheimer’s disease (AD) is a mental impairment and neural degeneration which causes progressive loss of memory and cognitive functions. This age-dependent illness is associated with extracellular amyloid plaques accumulation and twisted neurofibrillary tangles. Amyloid plaques are experimentally generated in animal models in order to investigate the disease process. In this study, we followed a rat model of AD for over a year. Wistar rats were divided randomly into two groups as control group (surgery without injection Aβ), and experimental group (two-sided intrahippocampal amyloid-beta injection into hippocampus). From each group, three animals were investigated 42 days after injection, and the remaining four animals were studied after one year. All animals were tested for learning abilities and memory. Finally, samples from blood, brain, heart, kidney, liver, colon and spleen were examined. In the experimental group, the size of amyloid plaques were increased significantly after one year and learning abilities and memory were concomitantly decreased. Onsets of various other conditions such as liver and kidney disorders, diabetes, and metabolic syndrome were observed, which indicates that the animals may be prone to cardiovascular disorders and ischemia.