Résumé
Oxiracetam (ORC) is a commonly used nootropic drug for improving cognition and memory impairments. The therapeutic effect and underlying mechanism of ORC in vascular dementia (VaD) treatment remain unknown. In this study, 3-month-old male Sprague-Dawley rats with permanent bilateral common carotid artery occlusion-induced VaD were treated orally with low (100 mg/kg) or high (200 mg/kg) dose ORC once a day for 4 weeks. The results of the Morris water maze test and Nissl staining showed that ORC treatment significantly alleviated learning and memory deficits and neuronal damage in rats with VaD. Mechanistically, the protein levels of a panel of genes associated with neuronal apoptosis (Bcl-2, Bax) and autophagy (microtubule-associated protein 1 chain 3, Beclin1, p62) were significantly altered by ORC treatment compared with VaD, suggesting a protective role of ORC against VaD-induced neuronal apoptosis and autophagy. Moreover, the Akt/mTOR pathway, which is known to be the upstream signaling governing apoptosis and autophagy, was found to be activated in ORC-treated rats, suggesting an involvement of Akt/mTOR activation in ORC-rendered protection in VaD rats. Taken together, this study demonstrated that ORC may alleviate learning and memory impairments and neuronal damage in VaD rats by altering the expression of apoptosis/autophagy-related genes and activation of the Akt/mTOR signaling pathway in neurons.