Total Astragalus saponins reduce astrocyte swelling and AQP4 expression following oxygen-glucose deprivation and reoxygenation by inhibiting the p38 pathway

doi:10.12122/j.issn.1673-4254.2026.02.06

Abstract

Abstract:

Objective To investigate the effect of total Astragalus saponins (AST) on astrocyte swelling induced by glucose-oxygen deprivation and reoxygenation (OGD/R) and its molecular mechanism. Methods Primary astrocytes isolated from the brain of post-natal day 2 SD rats were treated with solvent vehicle, AST, or AST combined with U-46619 (a p38 activator) 24 h prior to and during exposure to OGD/R. The changes in cell volume and morphology were observed, and intracellular reactive oxygen species (ROS) levels and lactate dehydrogenase (LDH) activity were detected. The expression of aquaporin 4 (AQP4) on cell membrane was observed using immunofluorescence confocal microscopy, and Western blotting was performed to detect the changes in p38 signaling pathway phosphorylation levels and AQP4 expression level. Results AST treatment significantly reduced OGD/R-induced increase in astrocyte volume, ROS levels and LDH release. The AST-treated cells also exhibited improved cell morphology, reduced aggregation of AQP4 on the cell membrane, and decreased p38 phosphorylation and AQP4 expression levels. The protective effects of AST against OGD/R-induced cell injuries were significantly attenuated by combined treatment of the cells with U-46619. Conclusion AST alleviate astrocyte swelling induced by OGD/R injury by inhibiting the activation of the p38 signaling pathway and AQP4 overexpression on the cell membrane.

Key words: total Astragalus glycosides, astrocyte swelling, aquaporin 4, p38 signaling pathway, oxygen-glucose deprivation/reoxygenation

Qin YIN, Yuxiao LEI, Xiaoshu WANG, Gang YANG, Zhaohua TANG. Total Astragalus saponins reduce astrocyte swelling and AQP4 expression following oxygen-glucose deprivation and reoxygenation by inhibiting the p38 pathway[J]. Journal of Southern Medical University, 2026, 46(2): 286-292.

Figures/Tables 5

Fig.1 Effects of total Astragalus saponins (AST) and U-46619 on astrocyte swelling following glucose-oxygen deprivation and reoxygenation (OGD/R). A: Effect of AST on astrocyte volume following OGD/R (n=5). B: Effect of AST on morphology of astrocytes following OGD/R (Original magnification: ×200). #P<0.05 vs control group, *P<0.05 vs OGD/R group, &P<0.05 vs AST group.

Fig.2 Effects of AST and U-46619 on intracellular ROS level in astrocytes following OGD/R (n=3, ×200). #P<0.05 vs control group; *P<0.05 vs OGD/R group.

Fig.3 Effects of AST and U-46619 on astrocyte injury following OGD/R (n=5). #P<0.05 vs control group; *P<0.05 vs OGD/R group; &P<0.05 vs AST group.

Fig.4 Effects of AST and U-46619 on phosphorylation of the p38 pathway in rat astrocytes following OGD/R (n=5). p-P38: Phosphorylated P38. #P<0.05 vs control group; *P<0.05 vs OGD/R group; &P<0.05 vs AST group.

Fig.5 Effects of AST and U-46619 on AQP4 protein aggregation on astrocyte membrane following OGD/R. A: Aggregation of AQP4 protein on astrocyte membrane in each group assessed by immunofluorescence staining (n=5, ×200). B: Expression of AQP4 protein on astrocyte membrane (m-AQP4) in each group assessed by Western blotting (n=5). #P<0.05 vs control group; *P<0.05 vs OGD/R group; &P<0.05 vs AST group.

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