Qingdu Decoction (QDT) is a traditional Chinese medicine (TCM) that was derived from Xiaochengqi Decoction, a famous decoction documented in the book of Treatise on Exogenous Febrile Disease in the Eastern Han Dynasty. According to our years of clinical application, QDT showed satisfactory efficacy in the treatment of endotoxemia in acute-on-chronic liver failure (ACLF). However, the underlying molecular mechanisms remain largely unknown.

In this study, we aimed to systematically evaluate the intervention effect of QDT on endotoxemia in rats and further clarify its potential regulatory mechanism.

The rat model of ACLF endotoxemia was induced by TAA and LPS + D-Gal. Then the rats were treated with clinical doses of QDT and lactulose. The rats were divided into four groups: CG, MG, QG and LG. The target microRNA was screened by high-throughput sequencing. The rat weight, liver index, hepatointestinal phenotype, serum biochemical indexes, mast cell activity, and hepatointestinal histopathology were used to evaluate the intervention effect. Western blot analysis was used to detect the expression levels of MAZ and its downstream genes ZO-1 and Occludin, and the expression levels of Zonulin and its downstream gene EGFR in colon. Finally, the expression of the miR-34c, MAZ, ZO-1, Occludin, miR-122a, Zonulin, and EGFR in colon was detected by qRT-PCR to further confirm the mechanism of the miR-34c/MAZ/TJs pathway and the miR-122a/Zonulin/EGFR pathway.

The rat weight, liver index, liver and colon phenotype, and serum biochemical indexes showed that QDT could significantly reduce liver and intestine injury and inhibit the progress of ACLF and endotoxemia. Toluidine blue staining and cytokine indexes showed that QDT could inhibit the activity of MCs and reduce the release of inflammatory factors. Mechanistically, QDT can inhibit the activity of MCs, activate miR-34c/MAZ/TJs pathway and miR-122a/Zonulin/EGFR pathway in colon, promote the recovery of intestinal barrier homeostasis, reduce and restore the damage of endotoxemia.

Our results suggested that QDT can significantly reduce rat ACLF endotoxemia by regulating the miR-34c/MAZ/TJs pathway and the miR-122a/Zonulin/EGFR pathway in colon.