Objective: To assess the possible antioxidant and anti-inflammatory activity of cyanidin from cherries on adjuvant induced arthritis (AA) in SD rats.
Method: Arthritis was induced by the complete Freud's adjuvant in male Sprague Dauley rats and assessed based on paw swelling. Rats were randomly divided into normal group (NM), adjuvant arthritis group (AA) and three cyanidin-treated groups in high dosage (HA), middle dosage (MA), and low dosage (LA). The morphological changes in the hind limbs were conducted under a light microscope. We detected glutathione (GSH) in whole blood and malonaldehyde (MDA), superoxide dismutase (SOD), total antioxidative capacity (T-AOC) activity in serum by special kits to assess the antioxidant effects of cyanidin on AA. Moreover, the prostaglandin E2 (PGE2) levels in paw tissues were determined by radioimmunoassay and TNF-alpha levels in serum were determined using ELISA kits specific for rat.
Result: The cyanidin could protect against the paws swelling in AA rats. From the day 14 after AA induction, the swellings of the cyanidin treated groups at high dosage and low dosage were significantly reduced compared with the model group (P < 0.05, 0.01). Histological examination of sections through the hind limbs revealed alleviation of inflammatory reaction in the joint after the treatment. The cyanidin at high and low dosage could increase the GSH, SOD activity and T-AOC levels in whole blood or serums and decrease MDA in AA rats (P < 0.01). The cyanidin could decrease the PGE2 levels in paw tissues and the TNF-alpha levels in serum at high and low dosages (P < 0.01).
Conclusion: The cyanidin could protect against the paws swelling in AA rats, and alleviate the inflammatory reaction in the joint, and the mechanism might be via the increase activity of GSH, SOD and T-AOC that improve the total antioxidative capacity and scavenge the free radicals, perhaps as a result of that the levels of the PGE2 in paw tissues and TNF-alpha contents in serum were decreased. The results suggest that the cyanidin from cherries could be one of the potential candidates for the alleviation of arthritis.