In the present study, AA was initiated in Sprague‑Dawley rats via intradermal immunization in the right hind metatarsal footpad with heat‑killed Mycobacterium butyricum in liquid paraffin, and rats were divided into four groups: Normal, AA rat model, CP‑25 (50 mg/kg) and methotrexate (0.5 mg/kg) groups (n=10 rats/group). However, the effect of CP‑25 on angiogenesis remains unclear. CP‑25 also exhibits a marked therapeutic effect on adjuvant‑induced arthritis (AA), and is able to inhibit synovial and immune cell function, according to our previous study. We previously demonstrated that CP‑25 exerts anti‑inflammatory and immunoregulatory effects.

Paeoniflorin‑6'‑O‑benzene sulfonate (CP‑25) is a novel ester derivative of paeoniflorin. Angiogenesis can produce an invasive and destructive front, also named a pannus, comprised of inflammatory vascular tissue that covers and erodes articular cartilage, subchondral bone and peri‑articular soft tissues in rheumatoid arthritis (RA).