title: The effects of a high-energy diet on hippocampal function and blood-brain barrier integrity in the rat.
abstract: Cognitive impairment and Alzheimer's disease are linked with intake of a Western diet, characterized by high levels of saturated fats and simple carbohydrates. In rats, these dietary components have been shown to disrupt hippocampal-dependent learning and memory processes, particularly those involving spatial memory. Using a rat model, the present research assessed the degree to which consumption of a high-energy (HE) diet, similar to those found in modern Western cultures, produces a selective impairment in hippocampal function as opposed to a more global cognitive disruption. Learning and memory performance was examined following 90-day consumption of an HE-diet in three nonspatial discrimination learning problems that differed with respect to their dependence on the integrity of the hippocampus. The results showed that consumption of the HE-diet impaired performance in a hippocampal-dependent feature negative discrimination problem relative to chow-fed controls, whereas performance was spared on two discrimination problems that do not rely on the hippocampus. To explore the mechanism whereby consuming HE-diets impairs cognitive function, we investigated the effect of HE-diets on the integrity of the blood-brain barrier (BBB). We found that HE-diet consumption produced a decrease in mRNA expression of tight junction proteins, particularly Claudin-5 and -12, in the choroid plexus and the BBB. Consequently, an increased blood-to-brain permeability of sodium fluorescein was observed in the hippocampus, but not in the striatum and prefrontal cortex following HE-diet access. These results indicate that hippocampal function may be particularly vulnerable to disruption by HE-diets, and this disruption may be related to impaired BBB integrity.
authors.affiliation: Department of Psychological Sciences, Purdue University, West Lafayette, IN 19104-6241, USA. kanoski@sas.upenn.edu
authors.forename: Scott E
authors.initials: SE
authors.lastname: Kanoski
authors.forename: Yanshu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Wei
authors.initials: W
authors.lastname: Zheng
authors.forename: Terry L
authors.initials: TL
authors.lastname: Davidson
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D001812:Blood-Brain Barrier / Q000378:metabolism / Q000503:physiopathology*; D001835:Body Weight; D003072:Cognition Disorders / Q000209:etiology* / Q000473:pathology*; D004041:Dietary Fats / Q000009:adverse effects*; D004193:Discrimination Learning / Q000502:physiology; D004195:Disease Models, Animal; D005508:Food Deprivation; D005786:Gene Expression Regulation / Q000502:physiology; D006624:Hippocampus / Q000378:metabolism*; D008297:Male; D018782:Maze Learning / Q000502:physiology; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D019108:Tight Junctions / Q000378:metabolism; D013997:Time Factors
chemical_list: D004041:Dietary Fats; D008565:Membrane Proteins