Fig. 5

Anti-arthritic efficacy of EOS in FCA-induced arthritic rats. a Clinical symptoms (left panels), b X-rays (middle panels), and c histological analysis (right panels, hematoxylin and eosin stained) of FCA-induced arthritic rats treated with distilled water (negative control), different doses of EOS (100, 200, and 400 mg/kg), and diclofenac sodium (positive control). FCA injection induced severe inflammation and bone destruction, which were evidenced via paw edema, bone degeneration, and osteoporotic lesions (arrows). Treatment with EOS suppressed hind paw swelling and bone destruction. Histological sections from the negative control group showed severe synovitis marked by the loss of cartilage tissue and the presence of numerous macrophages. Total score for synovitis recorded for the negative control group is 13 points. However, treatment with EOS significantly reduced the number of macrophages and increased the production of collagen fibrils (arrow heads). Total score for synovitis recorded for 100, 200 and 400 mg/kg doses of EOS are 10, 7 and 3 points, respectively. The anti-arthritic effect of EOS was comparable to that of diclofenac sodium (total score for synovitis recorded is 4 points). The data is presented as mean ± SD of 2 independent experiments in 6 replicates each