Vitamin E prevents high-fat high-carbohydrates diet-induced memory impairment: the role of oxidative stress

Abstract

Memory and learning are impaired by imbalanced diet consumption. High-fat high-carbohydrate diet (HFCD) induces oxidative stress, which results in neuronal damage and interference with synaptic transmission; hence, a decline in cognitive function. Vitamin E is a fat soluble antioxidant that is believed to have positive effects on learning and memory. In this study, we tested the hypothesis that chronic administration of vitamin E prevents learning and memory impairment induced by HFCD. In addition, possible molecular targets for HFCD, and vitamin E that lead to cognitive effects were examined. Vitamin E and/or HFCD were concurrently administered to animals for 6 weeks. Thereafter, behavioral studies were conducted to test the spatial learning and memory using radial arm water maze (RAWM). Additionally, brain derived neurotrophic factor (BDNF) level and antioxidant markers were assessed in the hippocampus. The results of this project revealed that HFCD impairs both short-term and long-term memories (p<0.05). The administration of vitamin E prevented the memory impairment induced by HFCD consumption (p<0.05). The consumption of HFCD reduced activities of hippocampal superoxide dismutase (SOD) and catalase (p<0.05); whereas the levels of thiobarbituric acid reactive substances (TBARS) and oxidized glutathione (GSSG) were elevated (p<0.05). The administration of vitamin E normalized the effect of HFCD on the oxidative stress markers. None of the treatments induced changes in the levels of BDNF or glutathione peroxidase (GPx). In conclusion, HFCD induces memory impairment, and the administration of vitamin E prevented this impairment probably through normalizing antioxidant mechanisms in the hippocampus.

Keywords: Diet; High-carbohydrate; High-fat; Hippocampus; Learning; Maze; Memory; Oxidative stress; Vitamin E.