Affiliations: [a] Department of Neurosciences and the Center on Aging, Medical University of South Carolina, Charleston, SC, USA | [b] Department of Psychology, Arizona State University, Tempe, AR, USA
Correspondence:
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Corresponding author: Ann-Charlotte Granholm, Department of Neurosciences, Center on Aging, Medical University of South Carolina, Charleston, SC 29425, USA. Tel.: +1 843 297 0652; Fax: +1 843 792 0679; E-mail: granholm@musc.edu; www.musc.edu/aging.
Abstract: Diets rich in cholesterol and/or saturated fats have been shown to be detrimental to cognitive performance. Therefore, we fed a cholesterol (2%) and saturated fat (hydrogenated coconut oil, Sat Fat 10%) diet to 16-month old rats for 8 weeks to explore the effects on the working memory performance of middle-aged rats. Lipid profiles revealed elevated plasma triglycerides, total cholesterol, HDL, and LDL for the Sat-Fat group as compared to an iso-caloric control diet (12% soybean oil). Weight gain and food consumption were similar in both groups. Sat-Fat treated rats committed more working memory errors in the water radial arm maze, especially at higher memory loads. Cholesterol, amyloid-β peptide of 40 (Aβ40) or 42 (Aβ42) residues, and nerve growth factor in cortical regions was unaffected, but hippocampal Map-2 staining was reduced in rats fed a Sat-Fat diet, indicating a loss of dendritic integrity. Map-2 reduction correlated with memory errors. Microglial activation, indicating inflammation and/or gliosis, was also observed in the hippocampus of Sat-Fat fed rats. These data suggest that saturated fat, hydrogenated fat and cholesterol can profoundly impair memory and hippocampal morphology.
