Pyrazole derivatives ameliorate synovial inflammation in collagen-induced arthritis mice model via targeting p38 MAPK and COX-2.

The type II collagen-induced arthritis (CIA) model and human rheumatoid arthritis exhibit similar characteristics. Both diseases involve the production of inflammatory cytokines and other mediators, triggering an inflammatory cascade linked to bone and cartilage damage. Recently, new pyrazole compounds with various pharmacological activities, including antimicrobial, anticancer, anti-inflammatory, and analgesic agents, have been reported. Our aim is to evaluate the therapeutic effectiveness of two newly synthesized pyrazole derivatives, M1E and M1G, in reducing inflammation and oxidative stress in a mouse model of collagen-induced arthritis. Arthritis was induced in DBA/1J mice, and the therapeutic effect of the M1E and M1G is assessed by measuring the arthritic index, quantifying the expression of inflammatory genes such as p38 MAPK, COX-2, IL1β, MMP3, and TNF-α using real-time PCR and analyzing protein expression using western blotting for phosphorylated p38 MAPK and COX-2. Oxidative stress markers and hind paws joint histopathology were also evaluated. Treatment with the two pyrazole derivatives significantly (p < 0.001) improved the arthritic score; downregulated the expression of inflammatory genes p38 MAPK, COX-2, IL1β, MMP3, and TNF-α; and reduced the protein expression of phosphorylated p3  MAPK and COX-2. In addition, both compounds ameliorated oxidative stress by increasing the activities of SOD and reducing the formation of MDA in the paw tissue homogenates. Both M1E and M1G significantly (p < 0.001) improved the pathological features of synovitis. The pyrazole derivatives, M1E and M1G, significantly reduced the arthritic score and the inflammatory cytokine expression, improved synovitis histopathology, and ameliorated oxidative stress in the CIA mice model.