Antioxidant effects of gold nanoparticles on early stage of collagen-induced arthritis in rats.

Objective: To determine antioxidant effects of prophylactic treatment with gold nanoparticles (AuNPs) in the early stage of collagen-induced arthritis (CIA).

Methods: The preventive treatment with 13 nm or 50 nm AuNPs injected intraarticularly (i.a.) was started at the induction day (0) of CIA and finished in the early stage of arthritis at the day 10. At the end of experiment blood indices (erythrocyte sedimentation rate, leukocyte and erythrocyte counts), pro-/antioxidant status of blood serum (the amount of malondialdehyde, catalase and total antioxidant activity), and internal organs' weight as well as the changes in the joint tissues and their microscopic structure were evaluated.

Results: Both 13 nm and 50 nm AuNPs showed antioxidant effect by increasing the level of catalase activity in the early stage of experimental arthritis. Preventive treatment with 50 nm more than with 13 nm AuNPs suppressed joint swelling. Histopathological asssesment revealed statistically significant reduction of synovial angiogenesis and erosion formation in the cartilage. Pilot transmission electron microscopy (TEM) analysis showed predominant accumulation of 13 nm in the synovial fibroblast lineage cells.

Conclusions: Intraarticular injections of 13 nm or 50 nm AuNPs showed an antioxidant action significantly raising catalase activity without causing negative effects on hematological indices. Prophylactic treatment with 50 nm more than with 13 nm AuNPs suppressed joint swelling, synovial angiogenesis and cartilage erosion in the initial stage of arthritis.