Pulsatilla decoction suppressed intestinal inflammation by reducing infiltration of innate immune cells and increasing lactic acid in the colon

Pulsatilla decoction (PD), a traditional Chinese medicine commonly used in Asian countries for ulcerative colitis (UC), has an unclear mechanism of action. In this study, the effects of PD were investigated in a mouse model of UC induced by dextran sulfate sodium (DSS). Histology and immunohistochemistry analyses were used to examine intestinal inflammation and leukocyte infiltration in colonic tissues. A Multi-Plex immunoassay was used to examine cytokine levels. Immunofluorescence double staining was employed to examine the expression of matrix metalloproteinase-7 (MMP-7) in immune cells. Our results showed that administration of PD in the DSS-induced colitis mouse model attenuated intestinal inflammation and markedly decreased colonic infiltration of innate immune cells. Immunohistochemical analyses revealed that PD inhibited MMP-7 expression in infiltrating leukocytes, including neutrophils and macrophages. PD increased the cytokine level of IL-6 in colonic tissues. PD exhibited a beneficial effect of probiotic microorganisms on the intestinal microbiome's balance as lactate was significantly increased in the colonic chyme. Importantly, lactic acid induction was confirmed by testing two lactobacteria. It is likely that polysaccharides of PD contributed to the benefits for lactobacteria in the colon. In conclusion, PD effectively suppressed intestinal inflammation in the DSS-induced colitis mouse model by reducing colonic infiltration of innate immune cells and increasing lactic acid in the colon. These findings shed light on the mechanism of action of PD in UC treatment and provide a basis for further research in this area.

 

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Publication History

Article published online:
16 November 2023