Rheumatoid arthritis is an autoimmune illness causing deformity, edema, and joint tenderness. Its long-term treatment burdens the healthcare system and leads to toxicity, and thus, finding safe, effective, and affordable therapies is essential. The current study aimed to exhibit the anti-arthritic activity of Carvone-loaded chitosan nanoparticles to treat Freund’s complete adjuvant (FCA) arthritis in rats. Healthy albino rats (n = 35) were distributed into seven groups. The 1st group worked as normal control, while the 2nd was arthritic control. The 3rd group received methotrexate (10 mg/kg/week). The 4th group received Carvone (60 mg/kg/day), while the 5th (30 mg/kg/day), 6th (45 mg/kg/day), and 7th (60 mg/kg/day) groups received Carvone-C-NPs, respectively. Nanoparticles, prepared by the ion gelation method, were characterized by zeta size, potential, scanning electron microscopy, and Fourier transform infrared microscopy. NPs have zeta size (78.82 ± 0.02 nm) and potential (19.96 ± 0.02 mV). A significant reduction was shown in paw swelling (5.52 ± 0.05 mm), arthritic score (2.81 ± 0.23), and rheumatoid factor (14.56 ± 0.68 IU/L) by Carvone-C-NPs. qRT-PCR results showed significant down-regulation of pro-inflammatory cytokines [TNF-α (0.25 ± 0.03), IL-1β (0.21 ± 0.06), IL-17a (0.16 ± 0.12), and IL-33 (0.15 ± 0.01)] and up-regulation of anti-inflammatory cytokines [IL-4 (0.85 ± 0.06) and IL-10 (0.66 ± 0.04)] in ankle joint of Carvone-C-NPs treated group. The radiographical and histopathological findings showed reduced pannus formation, joint swelling, and synovial hyperplasia in the Carvone-C-NPs treated group. Overall, it is concluded that Carvone-C-NPs have remarkable anti-arthritic activity and promising anti-inflammatory properties.
