Astaxanthin attenuates oxidative stress and inflammatory responses in complete Freund-adjuvant-induced arthritis in rats

Background Astaxanthin (ATX), a natural xanthophyll carotenoid, has shown to exert significant protective effects against various diseases via its antioxidant and anti-inflammatory properties. However, its potential role in arthritis is still not reported. Therefore, the aim of the present study was to investigate the potential anti-arthritic properties of ATX against complete Freund's adjuvant (CFA)-induced arthritis rats. Methods Adjuvant arthritis was induced by single intraplantar injection of complete Freund's adjuvant (CFA) in the left hind paw of adult female Wistar rats. ATX (25, 50 and 100 mg/kg) and indomethacin (5 mg/kg) were given orally from days 14 to 28. The anti-arthritic activity was evaluated through various nociceptive behavioral tests (mechanical allodynia, mechanical hyperalgesia, cold allodynia, and thermal hyperalgesia), paw edema assessment, and arthritis scores. Serum tumor necrosis factor-alpha (TNF-alpha), C-reactive protein (CRP) and cyclic citrullinated peptide (CCP) antibody levels were assessed. Moreover, malondialdehyde (MDA), nitrite, glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) levels were also evaluated. Results Oral administration of ATX (50 and 100 mg/kg) exhibited significant anti-arthritic activity via enhancing the nociceptive threshold, reducing paw edema and improving arthritis scores. Moreover, ATX treatment also markedly suppressed inflammatory and oxidative mediators in adjuvant-administered rats. Conclusions Our findings suggest that ATX possesses potential anti-arthritic activity, which could be attributed to its anti-inflammatory and antioxidant properties.