Xuetongsu ameliorates synovial inflammatory hyperplasia in rheumatoid arthritis by inhibiting JAK2/STAT3 and NF-κB signaling pathways.

ETHNOPHARMACOLOGICAL RELEVANCE

Synovial inflammatory hyperplasia is the key pathological process that leads to further joint damage in rheumatoid arthritis (RA) progress. Kadsura heteroclita (Roxb) Craib, also called Xuetong in Chinese Tujia ethnomedicine, is utilized for its medicinal properties, including promoting blood circulation, dispelling "wind evil", and relieving "damp evil". It has been used in the treatment of arthralgia and RA, within Tujia ethnomedicinal practices. Xuetongsu (XTS), the main component of Xuetong, has been shown to inhibit the proliferation of RA fibroblast-like synovial cells (RAFLS) cells. However, the molecular mechanism of XTS in RA treatment requires further investigation.

AIM OF THE STUDY

To observe the therapeutic effect of XTS on synovial inflammatory hyperplasia in rheumatoid arthritis, focusing on its underlying molecular mechanisms involving the janus kinase 2 (JAK2)/transducer/activator of transcription 3 (STAT3) and nuclear factor kappa B (NF-κB) signaling pathways.

MATERIALS AND METHODS

Protein-protein interaction (PPI) and molecular docking were used to find the main targets of XTS treatment for RA. In lipopolysaccharide (LPS)-induced RAFLS and RAW264.7 cells in vitro models, the levels of inflammatory cytokines were analyzed using enzyme linked immunosorbent assay (ELISA), and the expression of JAK2, STAT3, and NF-κB signaling pathways, as well as cyclooxygenase-2 (COX-2), were analyzed through western blotting test. A hemolysis assay was used to certify the biosecurity of XTS. A model of adjuvant arthritis (AIA) was established in 40 male rats, and different doses of XTS were administered, followed by an automatic blood routine, ELISA assay, hematoxylin and eosin (H&E) staining, and radiological analysis of the effect of no XTS on blood cytokines, histological changes, and improvement of posterior paw bone destruction in AIA rats. The protein levels of inflammatory cytokines were analyzed by immunofluorescence, immunohistochemistry, or Western blot. Finally, H&E staining was used to detect the damage of XTS on the heart, liver, spleen, lung, and kidney of AIA rats.

RESULTS

Our results demonstrate that XTS effectively inhibited LPS-induced inflammatory responses in RAFLS and RAW264.7 cells by modulating the JAK2/STAT3 and NF-κB signaling pathways. Moreover, XTS administration in the AIA rats model significantly ameliorated paw swelling. Histological analysis revealed that XTS also suppressed the inflammatory response in paw tissue by modulating the JAK2/STAT3 and NF-κB signaling pathways. Importantly, during the treatment, XTS exhibited excellent safety profiles, as it did not induce any abnormalities in blood routine parameters or cause organ damage in the rats.

CONCLUSIONS

Our findings highlight XTS as a promising natural agent for inhibiting synovial hyperplasia in RA. XTS holds great potential as an unprecedented natural agent for developing novel therapeutic strategies to target synovial hyperplasia in RA.