To explore the protective mechanism of Jianpi Mixture on diarrhea-predominant-irritable bowel syndrome mice. Methods. To observe the intestinal protection of Jianpi Mixture on intestinal tract of diarrhea-irritable bowel syndrome mouse model. The method for the content determination of serum immunoglobulin A (IgA), IgG, IgM, interleukins and tumor necrosis factor alpha (TNF?) was ELISA. The mRNA levels of IL-1?, IL-6 and TNF? were detected by Real?time quantitative in Colon tissue. The expressions of Trypsinogen, PAR2 and NF?B pathway were detected by Western blotting in Colon tissue and murine macrophage cell. The protective effect and influence on PAR2-NF?B pathway of Jianpi Mixture were studied. Results. Jianpi Mixture protected mice from diarrhea-predominant-irritable bowel syndrome which related to the decrease of IgA, IgM and IgG, the regulation of interleukins, and the inhibition of PAR2-NF?B pathway. It was found that the expression of PAR2 and NF-?B in peripheral blood decreased , and further more , Jianpi Mixture could inhibit PAR2 by reducing the expression of NF-? B via testing peripheral blood of model mice with intervention of Jianpi Mixture. Conclusions. Jianpi Mixture could alleviate the symptoms of IBS-D model mice and reduce the damage of intestinal tissue. A certain protective effect was played in the model mice by relieving the inflammatory response and immune response. During the process, our study showed that the protection for intestinal tissue was affected by reducing the expression of PAR2 and NF-? B with intervention of Jianpi Mixture.

Keywords: Jianpi Mixture (JPM), Diarrhoea-predominant irritable bowel syndrome (IBS-D), PAR2-NF?Bsignaling