Picrorhiza kurroa Inhibits Experimental Arthritis Through Inhibition of Pro-inflammatory Cytokines, Angiogenesis and MMPs

The present study investigates the anti-arthritic activity of Picrorhiza kurroa (PK), on formaldehyde and adjuvant-induced arthritis (AIA) in rat. Administration of Picrorhiza kurroa rhizome extract (PKRE) significantly inhibited joint inflammation in both animal models. In AIA-induced arthritic rat, treatment with PKRE considerably decreased synovial expression of interleukin-1 (IL-1), interleukin-6 (IL-6), tumor necrosis factor receptor-1 (TNF-R1) and vascular endothelial growth factor as compared with control. The anti-arthritic activity was found to be well substantiated with significant suppression of oxidative and inflammatory markers as there was decreased malonaldehyde, Nitric oxide, tumor necrosis factor alpha levels accompanied with increased glutathione and superoxide dismutase, catalase activities. Additionally, PKRE significantly inhibited the expression of degrading enzymes, matrix metalloproteinases-3 and matrix metalloproteinases-9 in AIA-induced arthritic rat. Histopathology of paw tissue displayed decreased inflammatory cell infiltration as compared with control. Taken together, these results demonstrated the anti-arthritic activity of PKRE against experimental arthritis, and the underlying mechanism behind this efficacy might be mediated by inhibition of inflammatory mediators and angiogenesis, improvement of the synovium redox status and decreased expression of matrix metalloproteinases. Copyright (c) 2015 John Wiley & Sons, Ltd.