Wu-Tou Decoction Inhibits Angiogenesis in Experimental Arthritis by Targeting VEGFR2 Signaling Pathway

Wu-tou decoction (WTD) is a classic traditional Chinese medicine formula and has been extensively used for the treatment of rheumatoid arthritis (RA). Previous reports indicate that WTD possesses anti-inflammatory and antinociceptive activities, and inhibits the development of arthritic joints and disease severity of collagen-induced arthritis (CIA) or adjuvant-induced rats; however, its action on angiogenesis of RA has not been clarified. This study aims to determine the anti-angiogenic activity of WTD in CIA rats and in various angiogenesis models. Our data showed that WTD (0.95, 1.9, and 3.8 g/kg) markedly reduced the immature blood vessels in synovial membrane tissues of inflamed joints from CIA rats. It also inhibited in vivo angiogenesis in chick embryo and VEGF₁₆₅-induced microvessel sprout formation ex vivo. Meanwhile, WTD suppressed VEGF₁₆₅-/MH7A-induced migration, invasion, adhesion, and tube formation of human umbilical vein endothelial cells (HUVECs). Moreover, WTD significantly reduced the expression of angiogenic activators, including vascular endothelial growth factor (VEGF), VEGFR2, interleukin (IL)-1β, IL-17, transforming growth factor-β, platelet-derived growth factor, placenta growth factor, angiopoietin (Ang) I and Ang II in synovium of CIA rats, and/or in HUVECs. More interestingly, WTD blocked the autophosphorylation of VEGF₁₆₅-induced VEGFR2 and consequently downregulated the signaling pathways of activated AKT, ERK1/2, JNK, and p38 in VEGF₁₆₅-induced HUVECs. These findings suggest for the first time that WTD possesses the anti-angiogenic effect in RA in vivo, ex vivo, and in vitro by interrupting the targeting of VEGFR2 activation.