Attenuating NF-κB/VCAM-1 Expression in the Middle Cerebral Artery Occlusion Model by Viola Odorata: Protection Against Ischemia-Reperfusion Injury in Rats

Introduction: The death of neurons and cerebral edema are the main consequences of stroke. However, inflammatory processes play key roles in aggravating cerebral damage following a stroke. This study aimed to investigate the effects of Viola odorata extract (VOE) on the infarct volume (IV), neurologic deficits (ND), and the expression of NF-κB and VCAM-1 in the Middle Cerebral Artery Occlusion (MCAO) model.

Methods: The animals were randomly separated into 6 groups: (1) control group, (2) vehicle-treated group, (3) MCAO group, (4) VOE25 group, (5) VOE50 group, and (6) VOE75 group (n= 12). VOE (25, 50, and 75 mg/kg) and distilled water were administered daily for 30 days. Two hours after the last gavage, the rats were exposed to MCAO for 60 minutes. Twenty-four hours later, IV, ND, and NF-κB/VCAM-1 expressions were evaluated.

Results: Viola odorata extract exhibited excellent neuroprotective effects by reducing IV (mainly in the core and subcortex areas), and induced downregulation of NF-κB and VCAM-1 expression.

Conclusion: Viola odorata could also activate intracellular pathways, reducing the expression of NF-κB and VCAM-1. It is useful for developing a novel medical herb for treating cerebral ischemia.

Highlights: A stroke occurs when the blood supply to a part of the brain is interrupted or reduced.Viola odorata extract (VOE) reduced the infarct volumes (IV) in rats' brains 24 h after middle cerebral artery occlusion (MCAO).VOE may decrease IV in the MCAO model by downregulating the NF-κB/VCAM-1 expression.

Plain language summary: A stroke is a medical condition in which poor blood flow to the brain results in cell death. After an interruption of blood flow, energy stores are rapidly depleted, and complex cellular cascades induce excitotoxic cell death. So far, no effective and specific treatment has been suggested for the stroke. In this study, the neuroprotective effects of the viola odorata extract (VOE) were screened. The V. odorata extract exhibited excellent neuroprotective effects by reducing infarct volume and inducing downregulation of NF-κB/VCAM-1 expression. This finding suggests that V. odorata may be useful for developing a novel medical herb for treating cerebral ischemia.