Efficacy of Artemisia annua Linné in improving cognitive impairment in a chronic cerebral hypoperfusion-induced vascular dementia animal model

Vascular dementia (VaD) is the second most common type of dementia after Alzheimer's disease. Currently, no FDA-approved drugs are available for the treatment of VaD. Artemisia annua Linné (AA) is known to have antioxidant properties, but its effects and mechanisms of action on cognitive impairment are still unknown.In this study, the improvement in cognitive impairment by AA in terms of protection against oxidative stress, neuroinflammation, and preservation of the integrity of the neurovascular unit (NVU) was assessed in an animal model of VaD with bilateral common carotid artery occlusion (BCCAO).Eight-week-old male Wistar rats were allowed to adapt for four weeks, and BCCAO was induced at 12 weeks of age. The rats were randomly assigned into four groups, with seven rats in each group: sham group without BCCAO, VaD group that received oral administration of distilled water after BCCAO surgery, and two AA groups that received oral administration of 150 mg/kg or 750 mg/kg AA after BCCAO surgery for 8 weeks. Nine weeks after BCCAO surgery, the cognitive function of the rats was evaluated and accumulated oxidative stress was assessed by immunohistochemistry, immunofluorescence, and western blotting. Damage to the components of the NVU was evaluated, and sirtuin (Sirt) 1 and 2 expression and nuclear factor-erythrocyte 2-associated factor 2 (Nrf2)/Kelch-like ECH-associated protein1 (Keap1) activation were investigated to assess the reduction in cell signaling and antioxidant pathways.BCCAO-induced cerebral perfusion decreased memory function and induced neuroinflammation and oxidative stress. But AA treatment mitigated cognitive impairment and reduced neuroinflammation and oxidative stress caused by chronic cerebral hypoperfusion. AA extracts activated the Nrf2/Keap1/activating antioxidant response elements pathway and maintained Sirt 1 and 2, subsequently leading to the maintenance of neurons, improved construct of microvessels, increased platelet-derived growth factor receptor beta, and platelet-endothelial cell adhesion molecule-1 associated with the blood-brain barrier integrity.AA is effective in alleviating BCCAO-induced cognitive decline and its administration may be a useful therapeutic approach for VaD.