Metabolic effects induced by chronic stress in the amygdala of diabetic rats: A study based on ex vivo 1H NMR spectroscopy

Diabetic patients are prone to suffer from multifarious stressful stimuli in a long-term, which play as an important risk factor for poor prognosis of the disease. Both human and rodent studies have clarified metabolic alterations in several brain regions of patients and experimental models with chronic stress exposure and diabetes. However, metabolic evidences for chronic stress related neurochemical changes in amygdala of diabetic brains have never been explored. We acquired H-1 nuclear magnetic resonance (H-1 NMR) with correlative analysis to study the characteristic metabolites in amygdala samples of diabetic rats under chronic stress exposure (Group DC), compared with non-chronic stress exposure diabetic rats (Group DM). Relative to Group DM, Group DC showed less exploratory activities and memory impairment in behavioral tests. Critically, quantitative and correlative analysis identified that spectra characteristics in amygdala between two groups were significantly different, and levels of various metabolites, such as lactate, tau, glutamate, glutamine, gamma-aminobutyric acid, creatine, N-acetylaspartate, choline, glycine, aspartic acid and alanine also showed statistically group differences. These results highlight that chronic stress mediated some major neurotransmitters and energy metabolism related neurochemical alterations in amygdala of diabetic rats. Collectively, these findings provide new insights for underlying metabolic mechanisms of chronic stress-related cognitive dysfunction in diabetes.