Cinnamon Counteracts the Negative Effects of a High Fat/High Fructose Diet on Behavior, Brain Insulin Signaling and Alzheimer-Associated Changes
Published: 12-13-2013 In Publication
Insulin resistance leads to memory impairment. Cinnamon (CN) improves peripheral insulin resistance but its effects in the brain are not known. Changes in behavior, insulin signaling and Alzheimer-associated mRNA expression in the brain were measured in male Wistar rats fed a high fat/high fructose (HF/HFr) diet to induce insulin resistance, with or without CN, for 12 weeks. There was a decrease in insulin sensitivity associated with the HF/HFr diet that was reversed by CN. The CN fed rats were more active in a Y maze test than rats fed the control and HF/HFr diets. The HF/HFr diet fed rats showed greater anxiety in an elevated plus maze test that was lessened by feeding CN. The HF/HFr diet also led to a down regulation of the mRNA coding for GLUT1 and GLUT3 that was reversed by CN in the hippocampus and cortex. There were increases in Insr, Irs1 and Irs2 mRNA in the hippocampus and cortex due to the HF/HFr diet that were not reversed by CN. Increased peripheral insulin sensitivity was also associated with increased glycogen synthase in both hippocampus and cortex in the control and HF/HFr diet animals fed CN. The HF/HFr diet induced increases in mRNA associated with Alzheimers including PTEN, Tau and amyloid precursor protein (App) were also alleviated by CN. In conclusion, these data suggest that the negative effects of a HF/HFr diet on behavior, brain insulin signaling and Alzheimer-associated changes were alleviated by CN suggesting that neuroprotective effects of CN are associated with improved whole body insulin sensitivity and related changes in the brain.
FIGURE 1: High Fat/High Fructose (HF/HFr) diet decreases Glut 1 and 3 in hippocampus and cortex. Open bar, control diet; solid bar, control diet plus cinnamon, mottled gray bar, HF/HFr diet; gray bar, HF/HFr diet plus cinnamon. Values are mean ± SE for 8 to 10 rats. Different letters denote significant differences among groups, p<0.05.
Richard A. Anderson mail, Bolin Qin, Frederic Canini, Laurent Poulet, Anne Marie Roussel
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