Therapeutic Effect of Curcumin Supplementation in the Modulation of NF-κB Responsive Genes in a Collagen-induced Arthritis Rat Model

Abstract

Aims: To assess the therapeutic effect of curcumin supplementation in modulating the expression of NF-κB in the joints of collagen-induced arthritis (CIA) rats. Place and Duration of Study: Department of Postgraduate Studies and Research, International Medical University, between July 2011 and May 2012. Methodology: Arthritis was induced in each group of Dark Agouti (DA) rats, by intradermal injection with collagen emulsified in complete Freund’s adjuvant. Treatment groups which were induced with CIA were treated with: 500 mg/kg curcumin; 1000 mg/kg curcumin; 2000 mg/kg curcumin; 25 mg/kg aspirin. Combination treatment groups which were induced with CIA were treated with: 500 mg/kg curcumin and 25 mg/kg aspirin; 1000 mg/kg curcumin and 25 mg/kg aspirin; 2000 mg/kg curcumin and 25 mg/kg aspirin from day 25 to 38. Efficacy was assessed based on ability to reduce paw oedema, histopathological changes, NF-κB expression, serum tumour necrosis factor alpha (TNF-α), interleukin 1-beta (IL-1β) and gluthathione peroxidase (GPx) levels. Results: Based on histopathological study, immunohistochemical scoring of NF-κB and ELISA analysis of TNF-α, IL-1β and GPx levels, our study found that curcumin given after arthritis in high doses, shows effects of healing and this results were comparable to positive control group, which is the arthritic group treated with 25 mg/kg aspirin. Curcumin given in combination with aspirin, showed better reduction in pathology in arthritic group compared to positive control group, especially with higher doses of curcumin. Conclusion: Curcumin was effective in reducing inflammatory changes seen in CIA joints which were proved through histopathological, immunohistochemical and biochemical analysis, however only at high doses.