Tinosporine alleviates collagen-induced arthritis in rats via modulating the gut microbiota-metabolome-immunity axis.

BACKGROUND

Rheumatoid arthritis (RA) is an inflammation-mediated autoimmune disease. Tinosporine (TIN), derived from Tinospora sinensis (Lour.) Merr. has significant anti-inflammatory and immunosuppressive effects. However, the anti-RA effect and mechanism of TIN have not been fully elucidated.

OBJECTIVE

This study elucidates the mechanism of TIN in alleviating collagen-induced arthritis (CIA) in rats based on the gut microbiome-metabolomic-immunity axis.

MATERIALS AND METHODS

We established CIA rat model to evaluate the efficacy of TIN. Based on 16S rRNA sequencing analysis, fecal metabolomics profiling and the concentrations of short-chain fatty acids determination to investigate the effect of TIN on gut microbiota composition and metabolome changes. Histopathology showed that TIN protected the intestinal barrier, then use ELISA and flow cytometry to analyze the mechanism of TIN, and qRT-PCR and WB were employed for verification.

RESULTS

TIN ameliorated joint damage and inflammation in CIA rats, histopathological observation confirmed that TIN had protective effect on intestinal barrier. 16S rRNA sequencing analysis and fecal metabolomics profiling confirmed that TIN intervention regulates the composition of gut microbiome and promote the propagation of probiotics, the abundance changes of 12 serum metabolites in the CIA group were reversed by TIN intervention. After intervention with TIN, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, and caproic acid rise significantly, but acetic acid cannot be reversed. Then ELISA and flow cytometry confirmed that TIN intervention could regulate the level of inflammatory factors, maintain the integrity of the intestinal barrier and restoring the imbalance of Th1/Th2 and Th17/Treg ratios in the colon of CIA rats.

CONCLUSION

TIN inhibited the inflammatory response of CIA rats by regulating the gut microbiome-metabolome-immunity axis, reversed the abnormalities of intestinal flora and differential metabolites, and maintained the integrity of the intestinal barrier.