Compound Kushen Injection Alleviates Experimental Colitis in Mice by Regulating Macrophage Polarization through TLR4/NF-κB Signaling.

OBJECTIVE

To explore the therapeutic effect and mechanism of Compound Kushen Injection (CKI) in dextran sulfate sodium (DSS)-induced ulcerative colitis (UC).

METHODS

Network pharmacology was used to predict the potential targets and pathways for CKI's therapeutic effects on UC. Thirty-five male C57BL/6 mice were randomized into 5 groups, including control, DSS model, 5-aminosalicylic acid (5-ASA), low- and high-dose CKI groups (n=7 per group). A 7-d protocol of ad libitum administration of 3% (w/v) DSS in drinking water was implemented to induce experimental colitis in mice of all groups except the control. Mice received daily intragastric 5-ASA (50 mg/kg), low-dose (2 mL/kg) or high-dose (4 mL/kg) CKI accordingly. In vivo therapeutic effects of CKI were evaluated via histology, ELISA and immunohistochemistry. In vitro, LPS-stimulated RAW264.7 inflammatory cells were treated with CKI for 24 h to detect cytokine changes. Immunofluorescence, flow cytometry and Western blot were applied to analyze macrophage polarization phenotypes in mouse peritoneal macrophages and RAW264.7 cells.

RESULTS

Network pharmacology analysis indicated that CKI's therapeutic effects on UC involved macrophage polarization regulation. CKI substantially alleviated DSS-induced colitis symptoms, improved intestinal barrier function, and reduced both pro-inflammatory cytokine secretion and oxidative stress in colonic tissues (P<0.05 or P<0.01). Upon DSS or LPS stimulation, CKI treatment markedly decreased M1 macrophage marker expression and increased M2 markers (P<0.05 or P<0.01). Mechanistic studies further revealed that CKI modulated macrophage polarization via Toll-like receptor 4 (TLR4)/nuclear factor-kappa B (NF-κB) signaling pathway (P<0.05 or P<0.01).

CONCLUSIONS

CKI alleviates experimental colitis in mice by modulating macrophage polarization, reducing inflammatory responses, and repairing the intestinal barrier; this effect may closely associated with inhibition of TLR4/NF-κB signaling pathway.