RESUMEN
ETHNOPHARMACOLOGICAL RELEVANCE: Xianglian Pill (XLP) is a classical Chinese medicine prescription applied for controlling ulcerative colitis (UC). Whereas, the underlying mechanism remains unclear. AIM OF THE STUDY: The present work was aimed to investigate the mechanism of XLP in dextran sulfate sodium (DSS)-induced UC via the Toll Like Receptor 4 (TLR4)/Myeloid Differentiation factor 88 (MyD88)/Nuclear Factor kappa-B (NF-κB) signaling in mice. MATERIALS AND METHODS: The major components of XLP were detected by high-performance liquid chromatography-diode array detection (HPLC-DAD). The ulcerative colitis model was induced by DSS in mice. 5-Amino Salicylic Acid (5-ASA) group and XLP group were intragastrically treated. Disease activity index (DAI) and colon length were monitored and hematoxylin-eosin (HE) staining was conducted. Gasdermin D (GSDMD)-N and TLR4 expressions in colon tissues were visualized by immunofluorescence. TLR4 mRNA was measured by Real Time Quantitative PCR (RT-qPCR). The expressions of NOD-like receptor thermal protein domain associated protein 3 (NLRP3), active-caspase-1, GSDMD-N, TLR4, MYD88, NF-κB, p-NF-κB, and the ubiquitination of TLR4 in colon tissues were detected by Western blot. Myeloperoxidase (MPO) enzyme activity was examined and serum inflammatory factors Interleukin (IL)-1ß, IL-6, Tumor Necrosis Factor-α (TNF-α), and IL-18 were determined by Enzyme-linked Immunosorbent Assay (ELISA). TLR4-/- mice were applied for verifying the mechanism of XLP attenuated DSS symptoms. RESULTS: The XLP treatment extended colon length, reduced DAI, and attenuated histopathological alteration in DSS-induced mice. XLP administration suppressed MPO activity and reduced the content of IL-1ß, IL-6, TNF-α and IL-18 in serum. XLP also inhibited the expression levels of GSDMD-N, TLR4, NLRP3, active-caspase-1, MyD88, p-NF-κB/NF-κB in colon tissues of DSS-induced mice. TLR4-/- mice proved that TLR4 was involved in XLP-mediated beneficial effect on DSS-induced ulcerative colitis. CONCLUSIONS: XLP might treat ulcerative colitis by regulating the TLR4/MyD88/NF-κB signaling pathway.