关键词: miR-21, 蛛网膜下腔出血, 神经炎症

Abstract: Objective To investigate the effect of miR-21 on neuroinflammation after subarachnoid hemorrhage (SAH) and its potential mechanism through in vitro and in vivo experiments. Methods In vitro,Transfection of N9 microglial cells with miR-21 mimics mediated by a transfection reagent was performed to upregulate miR-21 expression; a dual-luciferase reporter assay was conducted to verify that miR-21 can target and regulate the TLR4 gene; the effects of miR-21 overexpression on the TLR4/NF-κB inflammatory pathway were detected using RT-qPCR,Western Blot,and ELISA.In vivo,a rat SAH model was established by endovascular perforation,and miR-21 mimics were administered via intracerebroventricular injection.At 24 h post-modeling,neurological function was assessed using the modified Garcia score,and SAH severity was evaluated by the Sugawara score.TLR4 expression in the cerebral cortex was detected by immunohistochemistry and Western Blot. Results In vitro,Transfection with miR-21 mimics successfully upregulated miR-21 expression in N9 microglial cells; miR-21 was confirmed to target and regulate the TLR4 gene; overexpression of miR-21 inhibited the expression of TLR4,NF-κB,and related inflammatory factors.In vivo,overexpression of miR-21 significantly improved neurological function scores,reduced SAH severity,and suppressed the number of TLR4-positive cells and TLR4 protein expression in the cerebral cortex of SAH rats. Conclusion miR-21 alleviates neuroinflammation after SAH by targeting and inhibiting the TLR4/NF-κB signaling pathway and reducing the release of inflammatory factors,thereby exerting a neuroprotective effect.

Key words: miR-21, Subarachnoid hemorrhage, Neuroinflammation