Sleep deprivation (SD) is associated with cognitive deficits. It was found to affect the hippocampus region of the brain by impairing memory formation. This impairment is suggested to be caused by elevation in oxidative stress in the body, including the brain during SD. It was hypothesized that the methanolic extract of the fruits of Arbutus andrachne L. (Ericaceae) will prevent chronic SD-induced impairment of hippocampal memory via its antioxidative properties. The methanolic extract of the fruits of A. andrachne was evaluated for its beneficial properties to reverse SD-induced cognitive impairment in rats. Animals were sleep deprived for 8 weeks using a multiple platform model. The extract was administered i.p. at three doses (50, 200, and 500 mg/kg). Behavioral studies were conducted to test the spatial learning and memory using radial arm water maze (RAWM). In addition, the hippocampus was dissected to analyze the following oxidative stress markers: glutathione (GSH), oxidized glutathione (GSSG), GSH/GSSG, glutathione peroxidase (GPx), and catalase. Chronic SD impaired short- and long-term memories (P < 0.05). Treatment of animals with A. andrachne fruit extract at all doses prevented long-term memory impairment induced by SD while such treatment prevented short-term memory impairment only at 200 and 500 mg/kg dose levels. Moreover, A. andrachne fruit extract normalized the reduction in the hippocampus GSH/GSSG ratio and activity of GPx, and catalase (P < 0.05) induced by chronic sleep deprivation. Chronic sleep deprivation impaired both short- and long-term memory formation, while methanolic extract of A. andrachne fruits reversed this impairment, probably through normalizing oxidative stress in the hippocampus.
Keywords: Antioxidant; Arbutus andrachne; Hippocampus; Learning; Memory; Sleep deprivation.