Cognitive impairment is a prevalent but underestimated complication of diabetes, which can cause spatial memory and learning deficits. In the present study, a streptozotocin-induced type 2 diabetic rat model was employed to investigate the effects of vildagliptin, a new oral hypoglycemic agent that acts by inhibiting dipeptidyl peptidase-4, on diabetes-associated cognitive impairments, as well as the molecular mechanisms involved. The present findings demonstrated that vildagliptin treatment prevented memory impairment and decreased the apoptosis of hippocampal neurons. It also attenuated the abnormal expression of caspase-3, B cell lymphoma-2 (Bcl-2) and Bcl-2 associated X protein in the diabetic model. Vildagliptin treatment also reversed diabetes-induced decreases in phosphorylated (p)-protein kinase B (Akt) and p-glycogen synthase kinase 3β (GSK3β), brain-derived neurotrophic factor and nerve growth factor expression levels. The results indicated that the administration of vildagliptin exerts a protective effect against cognitive deficits by decreasing the expression of apoptosis-related proteins in the hippocampus and that this protective effect was mediated via the Akt/GSK3β signaling pathway.
Keywords: apoptosis; cognitive deficits; diabetes mellitus; dipeptidyl peptidase-4 inhibitor; protein kinase B/glycogen synthase kinase 3β pathway; vildagliptin.