Anti-inflammatory effect of Curcuma longa (turmeric) on collagen-induced arthritis: An anatomico-radiological study

Curcuma longa (CL) or turmeric is an Ayurvedic herb that has been traditionally used to treat inflammatory conditions like rheumatoid arthritis (RA). Collagen-induced arthritis (CIA) is a well established experimental auto-immune mediated polyarthritis in susceptible strains of rodents. The main aim of the study was to observe the inflammatory, macroscopic and radiological changes in the arthritic ankle joints of experimentally collagen-induced arthritis animals treated with or without CL extract. Thirty six male Sprague-Dawley (6-8 weeks-old, 150 ± 50) rats were equally divided into six groups. The first group served as a control while the rest five groups were immunized subdermally with 150 µg collagen type-II on day-0. All rats with established CIA with arthritis score (AS) exceeding 1 were treated orally with betamethasone (0.5 mg/ml/kg body weight) and varying doses of CL extract (30, 60 and 110 mg/ml/kg body weight) using olive oil as vehicle, daily for four weeks. Arthritic scoring (AS) of the paws, measurement of erythrocyte sedimentation rate (ESR) and paw thickness and radiological scoring were performed. Treatment with 110 mg/ml/kg CL showed significant mean difference in the ESR (p<0.01), AS (p<0.05) and radiological scores (p<0.01) on day-28 compared to the vehicle treated group. The mean difference for the ESR, AS and radiological scores of this highest CL dose group were found to be insignificant compared to the betamethasone treated group. The administration of CL extract arrested the degenerative changes in the bone and joints of collagen-induced arthritic rats.