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-α (TNF-α), 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.