Related Experiment Video
Updated: Mar 21, 2026
Brain Ventricular Microinjections of Lipopolysaccharide into Larval Zebrafish to Assess Neuroinflammation and Neurotoxicity
Published on: August 23, 2022
Inhibitory effects of spermidine on lipopolysaccharide-induced inflammation in RAW 264.7 cells
Hao Yuan1, Fang Peng1, Yi-Feng Zhou2
1Clinical Laboratory, Hunan Provincial People's Hospital, The First-Affiliated Hospital of Hunan Normal University, Changsha, Hunan 410005, P.R. China.
Abstract:
Spermidine (SPD) is a naturally occurring polyamine with anti-inflammatory and antioxidant properties. Given the pivotal role of macrophages in inflammatory pathogenesis (such as rheumatoid arthritis and autoimmune encephalomyelitis), the present study hypothesized that SPD exerts its anti-inflammatory effects by suppressing macrophage polarization. Briefly, RAW 264.7 cells were activated using lipopolysaccharide (LPS) and were treated with a vehicle control (complete DMEM) or varying SPD concentrations. The ratio of M1 and M2 macrophages in each group was determined using flow cytometry. Inflammatory gene expression and cytokine levels were determined using reverse transcription quantitative PCR and ELISA. The levels of NF-κB pathway-associated proteins were measured through western blotting. The findings revealed that the proportion of M1 cells gradually decreased with increasing SPD concentrations. In LPS-stimulated RAW 264.7 cells, SPD markedly decreased the expression of M1 marker genes and notably increased that of M2 marker genes. Furthermore, SPD decreased IL-6 levels and increased IL-10 levels. In addition, the levels of phosphorylated (p)-p65 and p-IκBα, which are NF-κB pathway-associated proteins, were markedly decreased after 24 h of SPD treatment. Overall, SPD treatment inhibited LPS-induced M1 polarization, reduced pro-inflammatory gene/cytokine expression and enhanced anti-inflammatory markers, potentially through NF-κB pathway modulation.
Insights
Spermidine (SPD) suppresses M1 macrophage polarization, reducing inflammation. This natural polyamine also enhances anti-inflammatory markers, potentially via NF-κB pathway modulation, offering therapeutic potential for inflammatory diseases.
Area of Science:
- Immunology
- Molecular Biology
- Pharmacology
Background:
- Macrophages play a key role in inflammatory diseases like rheumatoid arthritis.
- Macrophage polarization into M1 (pro-inflammatory) and M2 (anti-inflammatory) subtypes is critical in pathogenesis.
- Spermidine (SPD), a natural polyamine, possesses known anti-inflammatory and antioxidant properties.
Purpose of the Study:
- To investigate the effect of spermidine (SPD) on macrophage polarization.
- To determine if SPD can suppress M1 macrophage polarization and modulate inflammatory responses.
- To elucidate the potential mechanism involving the NF-κB pathway.
Main Methods:
- RAW 264.7 macrophage cell line stimulated with lipopolysaccharide (LPS).
- Treatment with varying concentrations of spermidine (SPD).
- Analysis of M1/M2 macrophage ratios via flow cytometry, gene expression (RT-qPCR), cytokine levels (ELISA), and NF-κB pathway proteins (Western Blot).
Main Results:
- SPD treatment dose-dependently decreased the M1 macrophage proportion.
- SPD significantly reduced M1 marker gene expression and increased M2 marker gene expression.
- SPD decreased pro-inflammatory cytokine IL-6 and increased anti-inflammatory cytokine IL-10.
- SPD inhibited the phosphorylation of NF-κB pathway proteins p-p65 and p-IκBα.
Conclusions:
- Spermidine (SPD) effectively inhibits LPS-induced M1 macrophage polarization.
- SPD treatment reduces pro-inflammatory gene and cytokine expression while enhancing anti-inflammatory markers.
- The anti-inflammatory effects of SPD may be mediated through the modulation of the NF-κB signaling pathway.
