Abstract
The genus of Trigonella has long been used for the treatment of arthritis and inflammatory disorders. This study was aimed to investigate the immunomodulatory activities of ethanol and n-hexane extracts of T. gharuensis in the rat model of rheumatoid arthritis. Freund's complete adjuvant (FCA) model was used to induce arthritis in rats. Arthritis was induced on day 0, while treatment which was started on day 8 continued for twenty days. Arthritic development and paw edema were determined using an arthritic scoring index and plethysmometer, respectively. Histopathology was evaluated using H&E staining. RNA extraction, reverse transcription, and polymerase chain reaction (RT-PCR) were performed to determine expression levels of proinflammatory markers such as TNF-α, NF-ĸB, IL-6, IL-1β, COX2, and anti-inflammatory cytokine IL-4. Prostaglandin E2 level (PGE2) was evaluated using ELISA. Blood analysis and biochemical parameters were also determined. The significance level was set as P < 0.05. Treatment with extracts reduced paw edema, arthritic progression, and histopathological parameters. Expression levels of abovementioned proinflammatory cytokines and COX2 were downregulated, while IL-4 was upregulated. PGE2 levels were found reduced with extract treatment. Blood parameters were nearly normalized in treatment groups. Extract treatment did not alter biochemical parameters. Both extracts had effects comparable with piroxicam. In conclusion, extracts of T. gharuensis ameliorated experimentally induced arthritis that may be ascribed to its immunomodulatory effects.