The anti-inflammatory effect of donepezil on experimental autoimmune encephalomyelitis in C57 BL/6 mice.

Donepezil is a potent and selective acetylcholinesterase inhibitor. It has been reported to restore cognitive performance in multiple sclerosis (MS) patients and experimental autoimmune encephalomyelitis (EAE) mice, an established model of MS. However, there are no reports about the anti-inflammatory effects of donepezil on EAE. In this study, the donepezil treatments on EAE mice were initiated at day 7 post immunization (7 p.i., subclinical periods, early donepezil treatment) and day 13 p.i. (clinical periods, late donepezil treatment) with the dosage of 1, 2 and 4 mg/kg/d respectively and the treatments persisted throughout the experiments. Blood-brain barrier (BBB) permeability was detected by Evan's blue content, the expression of matrix metalloproteinase-2 (MMP-2) and MMP-9, Akt and phosphorylated Akt (p-Akt) as well as nerve growth factor (NGF) and its precursor form (proNGF) in the brains of EAE mice were detected by Western blot, and the levels of interferon-γ and interleukin-4 in the splenocytes culture supernatants and brains of EAE mice were evaluated by ELISA. The results showed that the 2 mg/kg/d late donepezil treatment was the optimal dosage and could ameliorate clinical and pathological parameters, improve magnetic resonance imaging outcomes, reduce the permeability of BBB, inhibit the production of MMP-2 and MMP-9, modulate the expression of NGF and proNGF, increase Th2 bias and the phosphorylation of Akt in the brains of EAE mice. Our data suggested that the anti-inflammatory effects of donepezil may be a novel mechanism on treating EAE and provided further insights to understand the donepezil's neuroprotective activities in MS.