Modulatory Potential of Alpinetin on Inflammation, Oxidative Stress, Apoptosis, and Mitochondrial Dynamics in a Rat Middle Cerebral Artery Occlusion Model of Ischemic Stroke

Ischemic stroke initiates a complex cascade of pathophysiological events-including energy failure, excitotoxicity, oxidative stress, inflammation, apoptosis, and mitochondrial dysfunction-that together lead to extensive neuronal damage. Effectively targeting these interconnected mechanisms is crucial for achieving neuroprotection. Alpinetin, known for its antioxidant, anti-inflammatory, and cytoprotective properties, has shown promise as a potential therapeutic agent for cerebral ischemia in preliminary studies. However, the exact molecular mechanisms underlying its neuroprotective effects remain unclear. Therefore, this study aimed to investigate the multifaceted actions of alpinetin in a preclinically relevant right middle cerebral artery occlusion (Rt.MCAO) rat model, focusing on its impact on neuronal survival, inflammation, oxidative stress, apoptosis, and mitochondrial function. Forty male Wistar rats were randomly assigned to four groups: sham operation, Rt.MCAO + vehicle, Rt.MCAO + piracetam (250 mg/kg BW), and Rt.MCAO + alpinetin (100 mg/kg BW). We examined glial cell morphology, protein kinase B (Akt) expression, mitochondrial superoxide dismutase (MnSOD), myeloperoxidase (MPO), anti-apoptotic proteins, mitogen-activated protein kinase (p38 MAPK) and mitofusin-2 (Mfn2). Treatment with alpinetin for 3 days exerted robust neuroprotective effects by significantly reducing astrocytic and microglial activation through the downregulation of glial fibrillary acidic protein (GFAP) and ionized calcium-binding adaptor molecule 1 (Iba-1), restoring Akt expression, decreasing MPO activity, and enhancing MnSOD activity. Additionally, alpinetin modulated apoptotic signaling by lowering pro-apoptotic markers Bcl-2 Associated X-protein (Bax) and caspase-3 while increasing the expression of the anti-apoptotic protein B-cell lymphoma-extra large (Bcl-XL). It also attenuated p38 MAPK activation and preserved mitochondrial integrity by mitigating the decline in Mfn2 levels. Overall, these findings highlight the therapeutic potential of alpinetin in targeting multiple pathological processes involved in ischemic brain injury, supporting its promise as an effective treatment for stroke.