Intestinal anti-inflammatory effects of fuzi-ganjiang herb pair against DSS-induced ulcerative colitis in mice

Fuzi and ganjiang are widely used as traditional Chinese medicines (TCM) in China, Korea, Japan, and many other southeast Asian countries for treating ulcerative colitis (UC), emesis and heart failure for more than 1800 years. However, the underlying mechanism of fuzi, ganjiang and fuzi-ganjiang herb pair is still unclear. In our study, we explored the therapeutic effects of fuzi, ganjiang and fuzi-ganjiang herb pair against dextran sulfate sodium (DSS)-induced UC in mice model, along with the relevant mechanism. The contents of each marker compound in fuzi decoction (FD), ganjiang decoction (GD) and fuzi-ganjiang decoction (FGD) were determined using LC-MS/MS. During the experiment, bodyweight changes in each group were monitored every 5 days. On the day of sacrifice, colonic length, disease activity index (DAI) and spleen weight were also evaluated and histopathological examination was performed through hematoxylin & eosin (H&E) staining. The levels of myeloperoxidase (MPO) and inflammatory cytokines in colon tissues were determined by enzyme-linked immunosorbent assay (ELISA), and then the relative mRNA productions of inflammatory mediators, such as MPO, inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 were measured by real-time polymerase chain reaction (PCR). Involvement of MAPK, STAT3 and NF-κB signaling pathways in the pathogenesis of UC was determined in each group using Western Blot (WB) analysis. Compared with fuzi and ganjiang single decoction, the content of the alkaloids derived from fuzi (especially the diester alkaloid with strong toxicity, hypaconitine) in fuzi-ganjiang herb pair decoction was reduced. Additionally, the 6-gingerol, which was not found in ganjiang single decoction, was retained in fuzi-ganjiang herb pair decoction. FD, GD, and FGD significantly restored the bodyweight reduction, colon shortening, DAI elevation, splenomegaly and histological score in DSS-induced UC mice. Furthermore, except for the failure of low dosage of ganjiang decoction (GD-L) on IL-17A, all FD, GD and FGD significantly inhibited the production of MPO and inflammatory cytokines, such as IFN-γ, TNF-α, IL-1β, IL-6, IL-10 and IL-17A, and suppressed the relative expression of inflammatory mediators, such as MPO, iNOS and COX-2 mRNA in colon tissues of DSS-induced mice. According to WB analysis, fuzi, ganjiang and fuzi-ganjiang combination inhibited the activation of MAPK, NF-κB and STAT3 signaling pathways. Our study demonstrated that fuzi,