Total flavones of abelmoschus manihot enhances angiogenic ability both in vitro and in vivo

Angiogenesis is a process of new blood vessel formation from pre-existing vessels. It is a normal and vital process in growth and development, as well as in wound healing and in the formation of granulation tissue. Total flavones of Abelmoschus manihot (TFA) are the major constituents of the traditional Chinese herb Abelmoschus manihot L. Medic. The aim of this study is to investigate the effect of TFA on angiogenic ability using human umbilical vein endothelial cells (HUVECs) in vitro and chick chorioallantoic membrane (CAM) in vivo. HUVECs were treated with TFA at different concentrations. Cell viability, cell cycle progression, cell apoptosis, cell migration and tubular formation were investigated. The expression of vascular endothelial growth factor (VEGF) and kinase insert domain receptor (KDR, VEGFR-2) was examined by immunohistochemistry to identify mechanism of action of TFA. CAM model was used to evaluate the effect of TFA on angiogenesis in vivo. Our results showed that TFA promoted HUVECs proliferation in a dose- and time-dependent manner. It increased HUVECs migratory ability and the number of tubular structure, promoted vessel formation in HUVECs culture and CAM model. Furthermore, TFA treatment resulted in a decrease in cell apoptosis and enhanced the expression of VEGF and KDR. Taken together, TFA, as the major active component isolated from the traditional Chinese herb Abelmoschus manihot L. Medic, could enhance angiogenic ability of HUVECs in vitro and CAM in vivo. TFA may be used in the treatment of wound healing and ischemic/reperfusion injuries.