Changes of the histological morphology of rats ankle joints by H&E staining. The effect of PBP treatment on synovial inflammation was also assessed by histology. Wild-type rats showed no inflammation and destruction at all by H&E (A) from histopathology of the ankle joints, while model groups showed heavy cell infiltration, neovessel growth, synovial cell proliferation, and pannus formation in tissues of AA rats (B). Peptide treatment groups showed a less marked destruction and infiltration compared with model groups (C). Celecoxib treatment groups showed the same change as peptide treatment (D). (E): Effect of PBP on the clinical and pathological manifestations of rat adjuvant-induced arthritis. Note: 0: normal; 1: the extent of inflammatory cells' infiltration to the joint tissues; 2: synovial lining cell hyperplasia; 3: pannus formation; 4: joint cartilage layers destruction. *; P < 0.05 compared with normal. #; P < 0.05 compared with model.