Alpha-asarone ameliorates neurological deterioration of intracerebral hemorrhagic rats by alleviating secondary brain injury via anti-excitotoxicity pathways

•ASA ameliorates short- and long-term neurological impairments of ICH rats.•ASA alleviates ICH-induced secondary brain injury via multi-facet targets.•ASA reduces astrocyte activation and consequent neuroinflammation.•ASA inhibits neuro-excitotoxicity induced by glutamate-related calcium cascades.•ASA suppresses mitochondrial-involved neuro-apoptosis and neuronal autophagy. Secondary brain injury (SBI) has been confirmed as a leading cause for the poor prognosis of patients suffering from intracerebral hemorrhage (ICH). SBI co-exists in ischemia and hemorrhagic stroke. Neuro-excitotoxicity is considered the initiating factor of ICH-induced SBI. Our previous research has revealed alpha-asarone (ASA)'s efficacy against cerebral ischemia–reperfusion stroke by mitigating neuro-excitotoxicity. It is not yet known if ASA exhibit neuroprotection against ICH. This work aimed to investigate ASA's therapeutic effects and potential mechanisms of action against ICH in a classic rat model induced by collagenase Ⅶ injection. An in vivo ICH model of Sprague-Dawley rats was established by collagenase Ⅶ injection. We administrated different ASA doses (10, 20, or 40 mg/kg, i.p.) at 2 h post-ICH. Then, rats’ short- and long-term neurobehavioral function, bodyweight change, and learning and memory ability were blindly evaluated. Histological, Nissl, and flow cytometry were applied to assess the neuronal damage post-ICH. The wet/dry method and Evans blue extravasation estimated brain edema and blood-brain barrier function. Pathway-related proteins were investigated by immunofluorescence staining, enzyme-linked immunosorbent assay, and Western-blot analysis. The results demonstrated that ASA ameliorated neurological deterioration, bodyweight loss, and learning and memory ability of ICH rats. Histological, Nissl, and flow cytometry analyses showed that ASA reduced neuronal damage and apoptosis post-ICH. Besides, ASA probably mitigated brain edema and blood-brain barrier dysfunction via inhibiting astrocyte activation and consequent pro-inflammatory response. The mechanism investigation attributed ASA's efficacy to the following aspects: 1) promoting sodium ion excretion, thus blocking excitatory signal transduction along the axon; 2) preventing glutamate-involved pathways, i.e., decrease of N-methyl-d-aspartic acid receptor subunit 2B, increase of glutamate transporter-1, and alleviation of calcium-related cascades, mitochondrion-associated apoptosis, and neuronal autophagy; 3)