蛛网膜下腔出血（subarachnoid hemorrhage，SAH）是神经系统的急危重症，常有不良预后。临床研究 发现早期脑损伤（early brain injury，EBI）广泛存在于SAH患者中，可能是造成预后不良的重要原因。临床 前研究在了解EBI的机制方面取得了进展，小胶质细胞是参与EBI的主要细胞成分。EBI中的神经炎症主 要由M1型小胶质细胞驱动，参与血脑屏障破坏和神经元死亡；此外，M2表型小胶质细胞表现出减轻脑水 肿和改善神经功损伤的功能。因此，阐明SAH后小胶质细胞的极化及参与EBI的途径对干预SAH神经炎 症反应具有重要意义。

Subarachnoid hemorrhage (SAH) is a critical emergency in neurology, often associated with poor prognosis. Clinical studies have found that early brain injury (EBI) is widespread among SAH patients and may be a significant cause of poor outcomes. Preclinical research has made progress in understanding the mechanisms of EBI, with microglia being a major cellular component involved. The neuroinflammation in EBI is primarily driven by M1-type microglia, which participate in the disruption of the blood-brain barrier and neuronal death; additionally, M2-phenotype microglia exhibit functions that alleviate cerebral edema and improve neurological damage. Therefore, elucidating the polarization of microglia after SAH and their involvement in EBI pathways is of great significance for intervening in the neuroinflammatory response to SAH.