Astragali Radix Polysaccharides Promote M2 Polarization of OGD/R-induced BV2 Microglia by Inhibiting TLR4/NF-κB Signaling Pathway

Yanxi LIU; Lijun ZHANG; Qiule LI; Yayu ZENG; Yanjie HUO; Xiaodan LIU

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Astragali Radix Polysaccharides Promote M2 Polarization of OGD/R-induced BV2 Microglia by Inhibiting TLR4/NF-κB Signaling Pathway

VernacularTitle:黄芪多糖抑制TLR4/NF-κB信号通路促进OGD/R诱导的BV2小胶质细胞向M2型极化
Author: Yanxi LIU ¹ ; Lijun ZHANG ¹ ; Qiule LI ¹ ; Yayu ZENG ¹ ; Yanjie HUO ¹ ; Xiaodan LIU ¹
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1. School of Integrated Chinese and Western Medicine， Hunan University of Chinese Medicine；Hunan Provincial Key Laboratory of Integrated Traditional Chinese and Western Medicine for the Prevention and Treatment of Cardiovascular and Brain Diseases， Changsha 410208，China
Publication Type:Journal Article
Keywords: Astragali Radix polysaccharides （APS）; oxygen-glucose deprivation/reoxygenation model; BV2 microglial cells; lipopolysaccharide （LPS）; Toll-like receptor 4 （TLR4）/nuclear factor-kappa B （NF-κB） signaling pathway
From: Chinese Journal of Experimental Traditional Medical Formulae 2026;32(9):133-143
CountryChina
Language:Chinese
Abstract: ObjectiveTo investigate the effects of Astragali Radix polysaccharides （APS） on the polarization of BV2 microglial cells in an oxygen-glucose deprivation/reoxygenation （OGD/R） model through regulation of the Toll-like receptor 4 （TLR4）/nuclear factor-κB （NF-κB） signaling pathway. MethodsThe OGD/R injury model of BV2 microglia was established and divided into blank group， OGD/R group and APS group （0.4 g·L^-1 APS）. Neuroinflammatory injury was induced by lipopolysaccharide （LPS） and treated with APS. The cells were divided into blank group， LPS group （1 mg·L^-1 LPS） and APS group （0.4 g·L^-1 APS+1 mg·L^-1 LPS）. Cell viability was detected using the cell counting kit-8 （CCK-8） assay. Cell morphology was observed under an inverted microscope. Nitric oxide （NO） content in the cell supernatant was determined by the Griess assay. The secretion levels of tumor necrosis factor-α （TNF-α）， interleukin （IL）-6， IL-10， and IL-4 were measured by enzyme-linked immunosorbent assay （ELISA）. Immunofluorescence （IF） was used to detect the double-positive rates of ionized calcium-binding adapter molecule-1/inducible nitric oxide synthase （Iba-1⁺/iNOS⁺） and ionized calcium-binding adapter molecule-1/arginase 1 （Iba-1⁺/Arg1⁺）， as well as the nuclear translocation rate of nuclear factor-κB p65 （NF-κB p65）. Protein expression levels of Iba-1， iNOS， Arg1， TLR4， and NF-κB p65 were detected by Western blot. ResultsIn the OGD/R injury model， compared with the blank control group， BV2 microglial cells in the OGD/R group were activated and exhibited amoeboid morphological changes. The secretion levels of NO， TNF-α， and IL-6 were significantly increased （P<0.01）. The double-positive expression rate of Iba-1⁺/iNOS⁺ and the protein expression of Iba-1 and iNOS were significantly increased （P<0.01）. The nuclear translocation rate of NF-κB p65 and the protein expression levels of TLR4 and NF-κB p65 were significantly increased （P<0.01）. The levels of IL-10 and IL-4 were significantly decreased （P<0.01）， and the double-positive expression rate of Iba-1⁺/Arg1⁺ and Arg1 protein expression were significantly decreased （P<0.01）. Compared with the OGD/R group， the APS group （0.4 g·L^-1） showed reduced cell activation， significantly decreased secretion levels of NO， TNF-α， and IL-6 （P<0.01）， significantly decreased double-positive expression rate of Iba-1⁺/iNOS⁺ and relative protein expression of Iba-1 and iNOS （P<0.01）， significantly decreased nuclear translocation rate of NF-κB p65 and protein expression levels of TLR4 and NF-κB p65 （P<0.01）， significantly increased levels of IL-10 and IL-4 （P<0.01）， and significantly increased double-positive expression rate of Iba-1⁺/Arg1⁺ and Arg1 protein expression （P<0.01）. In the LPS-induced neuroinflammation model， compared with the blank control group， the LPS group showed increased cell activation， significantly increased levels of NO， TNF-α， and IL-6， significantly increased Iba-1⁺/iNOS⁺ double-positive expression rate， NF-κB p65 nuclear translocation rate， and protein expression levels of Iba-1， iNOS， TLR4， and NF-κB p65 （P<0.01）， while IL-10 and IL-4 levels， Iba-1⁺/Arg1⁺ double-positive expression rate， and Arg1 protein expression were significantly decreased （P<0.01）. Compared with the LPS group， the APS group showed reduced cell activation， significantly decreased levels of NO， TNF-α， and IL-6， Iba-1⁺/iNOS⁺ double-positive expression rate， NF-κB p65 nuclear translocation rate， and protein expression levels of Iba-1， iNOS， TLR4， and NF-κB p65 （P<0.01）， while IL-10 and IL-4 levels， Iba-1⁺/Arg1⁺ double-positive expression rate， and Arg1 protein expression were significantly increased （P<0.01）. ConclusionAPS may reduce microglial activation and promote their polarization toward the M2 phenotype by inhibiting activation of the TLR4/NF-κB signaling pathway， thereby alleviating the neuroinflammatory response induced by OGD/R.