• Weiping Chen, Zhiping Wu, Zhijuan Cheng, Yangbo Zhang, Qinghua Luo, and Min Yin.
• Department of Neurology, The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang 330006, Jiangxi Province, PR China; Institute of Neuroscience, Nanchang University, Nanchang 330031, Jiangxi Province, PR China; Jiangxi Provincial Clinical Medical Research Center for Neurological Disorders, Nanchang 330031, Jiangxi Province, PR China.
• Neuroscience. 2025 Feb 6; 566: 172717-27.

BackgroundMicroglia polarization plays a crucial role in inflammatory injury of brain following intracerebral hemorrhage (ICH). Heme oxygenase-1 (HO-1) has demonstrated protective properties against inflammation and promote hematoma clearance after ICH. The objective of this study was to explore impacts of HO-1 on microglia polarization and phagocytosis after ICH, along with the underlying mechanism.MethodsICH model was constructed in C57BL/6 mice. Neurological deficit of ICH mice was evaluated. HE detected pathological changes of mouse brain tissue. Immunofluorescence staining tested co-localization between HO-1 or NF-κB p65 and IBA1. The expressions of gene and proteins were detected by RT-qPCR and Western blot, respectively. Flow cytometry determined microglial polarization phenotype and neuron apoptosis. Cell viability of neuron was assessed by CCK-8. Red blood cells labeled by PKH-26 and co-cultured with microglia for examining microglial erythrophagocytosis.ResultsBoth HO-1 and NF-κB p65 phosphorylation were elevated in brain tissues of ICH mice. ZnPP, a HO-1 inhibitor, could exacerbate microglial M1 polarization and nerve injury, as well as repress microglial erythrophagocytosis in vitro and hematoma clearance in vivo. On the contrary, Tat-NBD, a NF-κB inhibitor, greatly suppressed microglial M1 polarization, and induced M2 polarization and microglial erythrophagocytosis, thus improving nerve injury and hematoma clearance after ICH. Notably, it was observed that NF-κB p65 could be activated by ZnPP treatment, and the regulatory roles of ZnPP on microglial polarization and erythrophagocytosis after ICH in vivo and in vitro were all diminished by Tat-NBD.ConclusionTherefore, our data demonstrated that HO-1 alleviated nerve injury and induced M2 polarization and phagocytosis of microglia after ICH via inhibiting NF-κB signaling pathway, which could provide deepen the pathological understanding of ICH and provide potential intervention targets and drug candidate for ICH.Copyright © 2024 International Brain Research Organization (IBRO). Published by Elsevier Inc. All rights reserved.

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