Ethanol Exacerbates the Alzheimer's Disease Pathology in the 5xFAD Mouse Model.

Alzheimer's disease (AD) is the most common form of dementia with characteristic biological markers. Clinically, AD presents as declines in memory, reasoning, and decision making, but the loss of memory is particularly associated with hippocampal damage. Likewise, excessive ethanol consumption has been found to disrupt hippocampal function and integrity. To assess the potential shared consequences of AD pathology and ethanol, 5xFAD mice were administered 5 g/kg ethanol daily for 10 days. Immunohistochemical analysis revealed ethanol and AD converged to lead to microglial and astrocytic senescence as well as increased Aß-plaque formation in the hippocampus. Despite the exacerbation of these potential mechanisms of neurodegeneration, there were no additive effects of ethanol exposure and AD-related genotype on Fluoro-Jade C (FJC)+ cells or cognitive deficits in the novel object recognition task. Overall, these results are the first to characterize the effects of ethanol exposure on early adulthood in the 5xFAD mouse model. Together these findings support the idea that alcohol can influence AD pathology; however, the mechanisms involved in AD progression (e.g., glial activation and Aß-plaque) may be impacted prior to evidence of pathology (e.g., cognitive decline or neuronal loss).