Cocos nucifera L. oil improved spatial and avoidance learning and memory of ovariectomized rats: role of oxidative stress

Menopause is associated with increased oxidative effects and induced learning and memory impairment. Considering the antioxidant effect of Cocos nucifera L. oil (CO) and the effect of that on memory impairment, this study was performed to investigate the antioxidant effects of CO on memory function caused by menopausal oxidative effects in ovariectomized (OVX) rats.Fifty female Wistar rats were randomly divided into ۵ groups and treated by CO ۱۰۰, ۲۰۰ and ۴۰۰ m/kg by oral gavage for ۵ weeks.The memory function was assessed with Morris water maze (MWM) and Passive avoidance (PA) tests. Serum, cortex and hippocampuswere collected for biochemical tests. latency and traveled distance in the OVX group were higher than in the Control group. The OVX-CO groups had a significantly lower traveled distance and latency compared to the OVX group. In OVX group, the brain tissue total thiol concentration, superoxidedismutase (SOD) and Catalase activities was significantly lower, and concentrations of malondialdehyde (MDA) were higher than in theControl group. Treatment by CO reversed these effects. In MWM and PA tests treatment by ۲۰۰ and ۴۰۰ mg/kg decrease scape latencyto find the plat form and latency to enter to the dark chamber. Also, treatment by two higher doses of CO decrease MDA concentrationand increase total thiol content and SOS/catalase activity. Our findings indicated that the effects of CO against ovariectomyinducedlearning and memory impairment were accompanied by reduced oxidative stress, and increased estradiol levels.

Keywords:

Cocos nucifera L. , Morris water maze , Ovariectomy , Oxidative stress.