Jing Si Herbal Tea Modulates Macrophage Polarization and Inflammatory Signaling in LPS-Induced Inflammation

Background: Sepsis is a lethal disease due to uncontrolled inflammatory responses. Macrophages play an important role in sepsis-associated inflammation. Jing Si Herbal Tea (JSHT) is a plant-based regimen with anti-inflammatory properties designed to treat respiratory diseases; however, its underlying therapeutic mechanism remains unclear. This study aimed to investigate the effects of JSHT on macrophage polarization and inflammatory signaling in lipopolysaccharide (LPS)-induced inflammation to provide therapeutic approaches for inflammatory diseases. Methods: RAW264.7 cells were stimulated with LPS (1 µg/mL for 16 h) to induce inflammatory responses and treated by JSHT (0.0125% concentration for 4 h) in the experimental groups (Control, JSHT, LPS, Pre-JSHT, and Post-JSHT groups). We investigated the protein and cytokine expression levels using western blotting and enzyme-linked immunosorbent assay (ELISA). Macrophage morphology was observed using immunofluorescence staining. The polarization surface markers were detected by flow cytometry. Results: In the LPS group, the expressions of the inflammatory signaling (pERK, pJNK, and nuclear NFκB) and the pro-inflammatory cytokine levels (TNF-α, IL-1β, and IL-6) were significantly increased, with M1 polarization (CD68+/CD80+) compared to the Control group. In the Pre-JSHT and Post-JSHT groups, the expressions of the inflammatory signaling and the pro-inflammatory cytokine levels were significantly decreased, with a higher M2 polarization ratio (CD163+/CD206+) compared to the LPS group. RAW264.7 cells exhibited filopodia protruding from the cell surface in the LPS group, which were inhibited in the Pre-JSHT and Post-JSHT groups. Conclusions: LPS induced M1 polarization with elevated inflammatory signaling and cytokine levels, while JSHT not only decreased M1 polarization but also promoted M2 polarization with decreased inflammatory responses. We propose JSHT as a potential anti-inflammatory agent against LPS-induced inflammation.