Though the exact etiology of rheumatoid arthritis (RA) is unknown, the contribution of immune cells in the disease process is completely acknowledged. T helper (Th) 1 and Th17-related cytokines are required for the disease development and progression, while Th2 and regulatory T cells (Tregs)-derived cytokines are protective. Studies have shown that sodium benzoate (NaB) can switch the balance of Th cell subsets toward Th2 and Tregs. The present study aimed to evaluate the possible effects of NaB on the expression of CD4+T cells-related cytokines and transcription factors in splenocytes derived from an animal model of RA, adjuvant-induced arthritis (AIA). AIA was induced in rats by injection of Freund's adjuvant containing mycobacterial antigens (Mtb). Splenocytes were isolated from AIA rats and restimulated ex vivo with Mtb in the presence or absence of NaB for 24 h. To determine the effects of NaB on the expression of T cells-related cytokine and transcription factor genes, real-time PCR was performed. NaB treatment of Mtb-stimulated splenocytes derived from arthritic rats resulted in significant increases in the gene expressions of Tregs-related cytokines (IL-10 and TGF-β) and Foxp3 transcription factor, and significant decreases in the expression of Th1-related cytokines (TNF-α and IFN-γ) and the T-bet transcription factor. The ratios of Th1/Th2 (IFN-γ/IL-4), Th1/Treg (IFN-γ/TGF-β and IFN-γ/IL-10) and Th17/Treg (IL-17/IL-10 and IL-17/IL-10+TGF-β)-related cytokines were also significantly decreased. In conclusion, NaB can potentially be considered as a useful therapeutic agent for the treatment of RA and other Th1 and Th17-mediated diseases.
Keywords: Adjuvant-induced arthritis; CD4 T cells; Cytokines; Sodium benzoate; Transcription factors.