Protective Effects of Nephelium lappaceum Rind Extract against Collagen-induced Arthritis in Dark Agouti Rats

Abstract

Pathogenic mechanisms of arthritis are studied using Collagen-Induced Arthritis (CIA) animal models. Plant derived antioxidants are known to reduce the inflammatory response in CIA. The aim of the study was to assess the protective efficacy of Nephelium lappaceum ethanol extract against Collagen-Induced Arthritis (CIA) in dark agouti rats. Arthritis was induced with 4 mg kg⁻¹ of collagen in complete Freund's adjuvant. CIA rats were orally treated with 100 and 200 mg kg⁻¹ per oral of N. lappaceum from day 25-50. Changes in body weight, joint thickness, C-reactive protein were recorded and immunohistochemistry for matrix metalloproteinase-13 (MMP-13) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) was done. N. lappaceum (100 and 200 mg kg⁻¹) significantly reduced (p<0.05) the arthritis-induced changes in body weight and paw edema. There was a significant reduction (p<0.05) in the C-reactive protein in the treatment groups. A significant reduction (p<0.05) in the arthritis-induced histopathological changes was seen after treatment with N. lappaceum. Treatment with N. lappaceum showed dose dependent effects on MMP-13 and TIMP-1 levels. N. lappaceum rind extract significantly suppressed the physiological, biochemical and histopathological changes produced during collagen-induced arthritis in dark Agouti rats. N. lappaceum extract supplementation may be beneficial in preventing the tissue damage and inflammatory conditions in arthritis.