Investigating the effects of Thymol on animal model of Rheumatoid Arthritis

BBackground & Objectives: Nowadays, attention to natural products with therapeutic potential has been increased. This study was carried out to investigate the effect of Thymol on the animal model of Rheumatoid arthritis (RA). Materials & Methods: RA was induced by injection of complete Freund's adjuvant into the footpad of Wistar rats. Then, rats were allocated in 3 groups: treated with Thymol (100 mg/kg-orally), treated with Prednisolone (100 mg/kg-orally) and un-treated group. All treatments were initiated at the 5th day after induction. The change in the dorso-plantar diameter of hands and legs of each rat were recorded every other day until 23 days after induction. Results: The edema and swelling of the soles of the feet of RA rats that received Thymol or prednisolone, were significantly decreased in a similar manner compared to RA rat without treatment. The serum levels of nitric oxide and myeloperoxidase correlated with the proliferation of spleen lymphocytes and the levels of IL-1 and IL-6 production were significantly decreased in treatment groups compared to control group rats. The level of decrease in the level of serum nitric oxide was higher in the thymol group compared to the prednisolone-induced group. Conversely, prednisone caused more decrease in the levels of IL-1 and IL-6 cytokines compared to RA rats that received thymol. Conclusion: Thymol may be considered as a useful strategy to control RA disease.