Donepezil ameliorates Aß pathology but not tau pathology in 5xFAD mice.

ABSTRACT

The cholinesterase inhibitor donepezil is used to improve Aß pathology and cognitive function in patients with Alzheimer's disease (AD). However, the impact of donepezil on tau pathology is unclear. Thus, we examined the effects of donepezil on Aß and tau pathology in 5xFAD mice (a model of AD) in this study. We found that intraperitoneal injection of donepezil (1 mg/kg, i.p.) exhibited significant reductions in Aß plaque number in the cortex and hippocampal DG region. In addition, donepezil treatment (1 mg/kg, i.p.) reduced Aß-mediated microglial and, to a lesser extent, astrocytic activation in 5xFAD mice. However, neither intraperitoneal/oral injection of donepezil nor oral injection of rivastigmine altered tau phosphorylation at Thr212/Ser214 (AT100), Thr396, and Thr231 in 5xFAD mice. Surprisingly, we observed that intraperitoneal/oral injection of donepezil treatment significantly increased tau phosphorylation at Thr212 in 5xFAD mice. Taken together, these data suggest that intraperitoneal injection of donepezil suppresses Aß pathology but not tau pathology in 5xFAD mice.