Salidroside ameliorates lipopolysaccharide‑induced ferroptosis in chondrocytes via regulation of the sirt1/foxo1 axis

Figures

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  Figure 1.. Target acquisition and enrichment analysis of SAL for ferroptosis in osteoarthritis. (A) Venn diagram of salidroside vs. OA target genes and ferroptosis targets. (B) PPI interaction network diagram of intersecting targets. (C) Biofunctional analysis of Gene Ontology for salidroside treatment of OA. OA, osteoarthritis; PPI, protein-protein interaction.

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  Figure 2.. KEGG enrichment analysis of SAL targets for the treatment of ferroptosis in osteoarthritis. (A) Target-pathway network diagram of core targets. (B) Map of the top 20 signaling pathways for Kyoto Encyclopedia of Genes and Genomes.

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  Figure 3.. SAL increases viability of LPS-induced chondrocytes and protects extracellular matrix from degradation. Viability of chondrocytes following LPS and SAL treatment for (A) 24 and (B) 48 h. (C) Toluidine blue staining plots of chondrocytes after intervention with SAL and LPS for 24 h. Scale bar, 100 µm. (D) Representative western blot analysis of (E) Col2, (F) Mmp3, (G) Mmp13, (H) Bax, (I) Bcl-2. ****P<0.0001, ***P<0.001, **P<0.01, *P<0.05 vs. LPS (1 µg/ml) + 0 µM SAL. LPS, lipopolysaccharide; SAL, salidroside; Col2, Collagen II; ns, non-significant.

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  Figure 4.. SAL attenuates LPS-induced ferroptosis in chondrocytes. (A) Electron microscopy was used to observe the morphology of chondrocytes following LPS and SAL treatment. Scale bar, 500 nm. (B) Representative western blot analysis of (C) Gpx4 and (D) SLC7A11. (E) GSH and (F) MDA content determination in chondrocytes. (G) BODIPY C11 probe incubation of chondrocytes to detect intracellular LPO fluorescence intensity. (H) DCFH-DA probe incubated chondrocytes to detect intracellular ROS fluorescence intensity. Scale bar, 100 µm. ****P<0.0001, ***P<0.001, **P<0.01, *P<0.05. vs. LPS. LPS, lipopolysaccharide; SAL, salidroside; ROS, reactive oxygen species; ns, non-significant; Gpx4 glutathione Peroxidase 4; SLC7A11, Solute Carrier Family 7 Member 11; GSH, Glutathione; MDA, Malondialdehyde; LPO, Lipid Reactive Oxygen Species.

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  Figure 5.. SAL alleviates intracellular ferroptosis in chondrocytes by modulating the sirt/FoxO1 pathway. (A) Representative western blots of (B) sirt1 and (C) p-FoxO1. (D) 2D and 3D molecular docking of SAL with Sirt1 and FoxO1. (E) Representative western blots of (F) sirt1, (G) p-FoxO1, (H) Gpx4 and (I) SLC7A11 following nicotinamide treatment. ****P<0.0001, ***P<0.001, **P<0.01, *P<0.05. vs. LPS. SAL, salidroside; LPS, lipopolysaccharide; sirt1, silent information regulator 1; p-FoxO1, phosphorylated Forkhead box protein O1; Gpx4, Glutathione Peroxidase 4; SLC7A11, Solute Carrier Family 7 Member 11.