Propofol alleviates M1 polarization and neuroinflammation of microglia in a subarachnoid hemorrhage model

Subarachnoid hemorrhage (SAH) is a devastating stroke caused by ruptured intracranial aneurysms, leading to blood accumulation around the brain. Early brain injury (EBI) within 72 h post-SAH worsens prognosis, primarily due to intense neuroinflammation. Microglia, pivotal in central nervous system defense and repair, undergo M1 to M2 polarization post-SAH, with M1 exacerbating neuroinflammation. Propofol (PPF), an anesthetic with anti-inflammatory properties, shows promise in mitigating neuroinflammation in SAH by modulating microglial activation. It likely acts through microRNAs like miR-140-5p, which attenuates microglial activation and inflammation by targeting TREM-1 and the NF-κB pathway. Understanding these mechanisms could lead to new therapeutic approaches for SAH-related EBI. In this study, BV-2 cell was used to establish in vitro model of SAH, and the expression of miR-140-5p and TREM-1 was detected after modeling. Microglial activity, apoptosis, the inflammatory pathway and response, oxidative damage, and M1/M2 polarization of microglia were evaluated by drug administration or transfection according to experimental groups. Finally, the targeting relationship between miR-140-5p and TREM-1 was verified by dual luciferase reporter assays, and the effect of PPF on the miR-140-5p/TREM-1/NF-κB signaling cascade was evaluated by RT‒qPCR or Western blotting. PPF effectively mitigates apoptosis, neuroinflammation, oxidative damage, and M1 microglial polarization in SAH. In SAH cells, PPF upregulates miR-140-5p and downregulates TREM-1. Mechanistically, PPF boosts miR-140-5p expression, while TREM-1, a downstream target of miR-140-5p, inhibits NF-κB signaling by regulating TREM-1, promoting M1 to M2 microglial polarization. Reduced miR-140-5p or increased TREM-1 counters PPF's therapeutic impact on SAH cells. In conclusion, PPF plays a neuroprotective role in SAH by regulating the miR-140-5p/TREM-1/NF-κB signaling axis to inhibit neuroinflammation and M1 polarization of microglia.