Amelioration of autoimmunity and inflammation by zinc oxide nanoparticles in experimental rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease that affects the lining of the synovial joints and approximately affects 0.5 − 1% of the total population imposing a socioeconomic burden. The current study aimed at investigating the novel possible beneficial effects of using zinc oxide nanoparticles (ZnO NPs) on such devastating disease. The complete Freund’s adjuvant (CFA) model was used to mimic RA in rats where ZnO NPs were given orally (2 mg/kg/day) daily for 14 days; and diclofenac Na, the standard drug, was given intraperitoneally (1 mg/kg/da y) the day after CFA, daily for 14 days. Our results displayed that ZnO NPs attenuated adjuvant-induced increased production of inflammatory mediators interleukin-1β (IL-1β), tumor necrosis factor alpha (TNF-α), interleukin-10 (IL-10), and total leukocyte count. Besides, they ameliorated autoimmunity through suppression of anti-citrullinated protein auto antibodies (anti-CCP) levels in rats. In conclusion our results highlight the benefits which could be obtained of nanoparticles either alone or in combination with the known anti-arthritic and/or anti-inflammatory agents, giving rise to new protocols to maximize the control of RA. Graphical abstract