Dachaihu decoction alleviates septic liver injury by modulating the intestinal barrier dysfunction and suppressing the NF-κB/NLRP3/Caspase-1 signaling pathway

BACKGROUND: Intestinal barrier dysfunction is a key driver of septic liver injury (SLI). Dachaihu decoction (DCHD), a classic traditional Chinese medicine formula recorded in the Treatise on Cold Damage, is widely used to treat gastrointestinal and hepatic inflammatory conditions. The primary objective of our research was to elucidate the protective effects of DCHD against SLI and the underlying molecular mechanisms. METHODS: In a murine model of sepsis induced by cecal ligation and puncture (CLP), we evaluated the therapeutic effects of DCHD on SLI by assessing serum liver enzymes, histopathology, oxidative stress, hepatocyte apoptosis, and inflammatory cytokines. Intestinal barrier integrity was examined via transmission electron microscopy, serum biomarkers (D-lactate, DAO, LPS), and tight junction proteins (ZO-1, Occludin, E-cadherin). Gut microbiota composition was analyzed using 16S rRNA sequencing. Chemical profiling of DCHD was performed via UPLC-Q-TOF-MS. Integrated network pharmacology, bioinformatics, and transcriptomic analyses identified the NF-κB/NLRP3/Caspase-1 axis as a potential mechanism, which was validated in vivo and in LPS-stimulated immortalized mouse Kupffer cells (ImKCs). Functional involvement of TLR4 and NLRP3 was further confirmed by genetic silencing of TLR4 with siRNA and pharmacological inhibition using TAK-242 (TLR4 inhibitor) and MCC950 (NLRP3 inhibitor). RESULTS: DCHD treatment attenuated liver injury in CLP-induced septic mice, as evidenced by improved liver function, attenuated histopathology, reduced oxidative stress, suppressed inflammation, and decreased hepatocyte apoptosis. These hepatoprotective effects were associated with reduced intestinal permeability and enhanced barrier integrity, alongside gut microbiota remodeling characterized by enrichment of beneficial bacteria and reduced abundance of gram-negative genera (e.g., Klebsiella, Enterobacter, Proteus), leading to decreased LPS production and translocation to the liver. Integrated network pharmacology and transcriptomics revealed the NF-κB/NLRP3/Caspase-1 axis as a central mechanism, with DCHD downregulating p-p65, p-IκBα, NLRP3, ASC, and Cleaved Caspase-1 in vivo and in LPS-stimulated ImKCs. Functional validation using TLR4 siRNA and the inhibitors TAK-242 and MCC950 confirmed that DCHD might attenuate liver inflammatory injury primarily through the NF-κB/NLRP3/Caspase-1 signaling pathway. CONCLUSION: DCHD may alleviate SLI by enhancing the intestinal barrier, potentially reducing the translocation of gut-derived LPS to the liver, and subsequently inhibiting the NF-κB/NLRP3/Caspase-1 axis, highlighting its considerable translational potential for SLI therapy.