Stigmasterol ameliorates Freund's complete adjuvant-induced polyarthritis in rats

To evaluate the anti-arthritic and disease-modifying potential of stigmasterol (STG), a plant-derived bioactive compound, in Freund's Complete Adjuvant (FCA)-induced polyarthritis in rats.

Experimental arthritis was induced in albino Wistar rats using FCA. The anti-arthritic efficacy of STG was assessed through primary and secondary paw edema, arthritis index, and body-weight changes. Biochemical, haematological, and immunological parameters were evaluated, along with mRNA expression of key mediators using RT-PCR. Histopathological analysis of bone, kidney, and spleen tissues, as well as macroscopic and radiographic joint assessments, was performed. STG was administered orally at doses of 150 and 300 mg/kg and compared with methotrexate (MTX).

FCA induction produced severe arthritic manifestations, including marked paw swelling, an elevated arthritis index, increased rheumatoid factor and anti-cyclic citrullinated peptide levels, and upregulation of inflammatory mediators (TNF-α, NF-κB, IL-1β, IRAK, and IL-17), along with radiographic joint damage and histopathological abnormalities. STG treatment significantly reduced paw edema, improved arthritis severity, and normalized biochemical and haematological parameters in a dose-dependent manner. The higher dose (300 mg/kg) showed efficacy comparable to MTX and significantly enhanced IL-10 expression, indicating restoration of immune balance.

Stigmasterol exhibits potent anti-arthritic, disease-modifying, and organ-protective effects in FCA-induced arthritis, highlighting its therapeutic potential in arthritis management.