The cognitive and noncognitive behavioral effects of a high-fat diet in the rTg4510 tau mouse model.

Alzheimer's disease drastically impacts cognitive and noncognitive behaviors in both humans and animal models. Two hallmark proteins in AD, amyloid-beta plaques and tau neurofibrillary tangles, accumulate in regions of the brain critical for learning and memory, including the hippocampus. Poor dietary choices have been shown to exacerbate cognitive deficits seen in AD. In this study, we assessed the effects of a high-fat diet (HFD - 60 kcal% fat) on cognitive & noncognitive behaviors as well as brain markers in the rTg4510 tau mouse model. Tau mice traveled a greater distance in the open field (OF) task (p < 0.05) and made more open arm entries and head dips (p < 0.05) than WT mice in the elevated zero maze. While all mice learned the Morris Water Maze (MWM) task, on the last day of acquisition tau females had significantly higher latency to find the platform than tau males (p < 0.01). Mice given the HFD spent significantly less time in the target quadrant than CD mice by the end of training (p < 0.05). Noncognitive behaviors were also affected; tau mice showed impaired burrowing (p < 0.05) and nesting (p < 0.001) compared to WT mice. In the brain, tau mice had greater levels of glial fibrillary acidic protein (GFAP) (p < 0.05) and significantly less hippocampal cell density than WT mice (p < 0.001). These results highlight the importance of dietary choices, especially in older populations more susceptible to AD and its effects.