Synergistic effects of fecal microbiota transplantation and andrographolide on gut microbiota modulation in dextran sulfate sodium-induced colitis in mice.

Background: Andrographolide (Andro) and fecal microbiota transplantation (FMT) are emerging treatments for colitis. However, whether their combined administration provides superior efficacy has not been established. Methods: This study attempted to clarify the reparative effects of FMT, Andro, and their combination on colitis in mice. Research subjects were allocated to: (1) the Control (CTRL) group, (2) the dextran sulfate sodium (DSS) group, (3) the FMT group, (4) the Andro group, and (5) the Andro combined with FMT group. The experiment lasted 15 days, during which weight, colon length, and hematochezia were monitored. Colon tissues were histologically analyzed via HE staining to assess inflammatory infiltration. The concentrations of key serum inflammatory factors were measured using ELISA. WB and IHC were employed to quantify inflammatory factor levels in intestinal tissues. Finally, the taxonomic composition of colonic microbiota was examined with 16S rRNA gene sequencing. Results: All three treatments mitigated colitis, as indicated by lowered pathological body weight wasting, colon shortening, hematochezia, and inflammation. Serum and intestinal cytokine levels were significantly decreased following treatment. Mechanistic analysis indicated that Andro attenuated inflammatory responses primarily through inhibition of NF-κB. Moreover, 16S rRNA sequencing revealed a beneficial modulation of the gut microbiota by all three treatments compared with the DSS group. Integrated analysis demonstrated that Andro combined with FMT therapy produced superior therapeutic outcomes relative to either intervention alone. Conclusion: The combined administration of Andro and FMT provides enhanced protection against DSS-induced colitis in mice, highlighting a potential synergistic therapeutic strategy.