Triptolide alters intestinal bacteria and ameliorates progression of rheumatoid arthritis in mice

Abstract Background Triptolide is a natural compound with immunosuppressive properties. Triptolide has used as a traditional Chinese medicine to treat rheumatoid arthritis (RA). We explore the effects of triptolide on intestinal bacteria and its potential role in alleviating RA progression in mice. Methods We randomly assigned thirty-six mice to six of the following groups: Con group, adjuvant-induced arthritis (AIA) group, Htrip group, Mtrip group, Ltrip group and Cele group. We collected tissue and blood samples as well as peritoneal macrophages to assess the effects of triptolide on the response to AIA through physical examinations, ELISA and PCR. We used 16S rDNA gene sequencing to analyze the intestinal flora of AIA mice treated with triptolide. Western blot was used to identify the potential influences on the TLR4/NF-κB pathway, ZO-1 and Occludin. Results Our findings showed that triptolide led to a significant reduction in the arthritic index score and paw swelling. It also improved intestinal barrier function by upregulating ZO-1 and Occludin. Furthermore, triptolide treatment caused changes in the intestinal flora by increasing the abundance of beneficial bacteria while decreasing harmful bacteria. Finally, our study demonstrated that triptolide inhibited TLR4/NF-κB, which contributed to its suppressive effects on inflammation. Conclusion In summary, our results suggest that triptolide can significantly alleviate the inflammatory response in AIA mice and, at the same time, promote recovery of intestinal barriers. Its mechanism may potentially be mediated by the intestinal flora through the TLR4/NF-κB pathway.