Abstract
Stroke is the leading cause of death worldwide. Dipeptidyl peptidase-4 (DPP-4) inhibitors are a class of anti-diabetic drugs for treatment of type-2 diabetes mellitus. The aim of this study is to evaluate the possible neuroprotective effect of a dipeptidyl peptidase-4 inhibitor, vildagliptin, independent of its anti-diabetic properties in non-diabetic rats subjected to cerebral ischemia. Anesthetized Wistar rats were subjected to either left middle cerebral artery occlusion (MCAO) or sham operation followed by reperfusion after 30 min of MCAO. The other three groups were orally administered vildagliptin at 3 dose levels (2.5, 5, 10 mg/kg) for 3 successive weeks before subjected to left focal cerebral ischemia/reperfusion and till the end of the study. Neurological deficit scores and motor activity were assessed 24 h following reperfusion. Forty-eight hours following reperfusion, rats were euthanized and their left brain hemispheres were harvested and used in biochemical, histopathological, and immunohistochemical investigations. Vildagliptin pretreatment improved neurological deficit score, locomotor activity, and motor coordination in MCAO rats. Moreover, vildagliptin reduced malondialdehyde (MDA), elevated reduced glutathione (GSH), phosphotylinosital 3 kinase (PI3K), phosphoryated of protein kinase B (p-AKT), and mechanistic target of rapamycin (mTOR) brain contents in addition to reducing protein expression of caspase-3. Also, vildagliptin showed a dose-dependent attenuation in neuronal cell loss and histopathological alterations in MCAO rats. This study proves that vildagliptin exerted a neuroprotective effect in a dose-dependent manner as shown in the attenuation of the infarct area, neuronal cell loss, and histopathological damage in MCAO rats, which may be mediated by attenuating neuronal and motor deficits, its antioxidant property, activation of the PI3K/AKT/mTOR pathway, and its anti-apoptotic effect.