MECHANISM OF ANGIOGENIC EFFECTS OF SAPONIN FROM GINSENG RADIX-RUBRA IN HUMAN UMBILICAL VEIN ENDOTHELIAL-CELLS

1 The effects of saponin from Ginseng Radix rubra on angiogenesis (tub e formation) and its key steps (protease secretion, proliferation and migration) in human umbilical vein endothelial cells (HUVEC) were exam ined to elucidate the mechanism of the tissue repairing effects of Gin seng Radix rubra. The effect on a wound healing model was also studied . 2 Tube formation was measured by an in vitro system. The activity an d immunoreactivity of tissue-type plasminogen activator OPA) as a prot ease for angiogenesis and the immunoreactivity of its inhibitor, plasm inogen activator inhibitor-1 (PAI-1), were measured in conditioned med ium of HUVEC stimulated for 24 h with saponin. Cell proliferation was measured by counting the cell numbers at 2-7 days after seeding. Migra tion was measured by Boyden's chamber method. The effect on wound heal ing was studied in the skin of diabetic rats. 3 Saponin at 10-100 mu g ml(-1) significantly stimulated tube formation by HUVEC in a dose-dep endent manner. Saponin in a similar concentration-range increased the secretion of tPA from HUVEC as estimated by immunoreactivity and enzym e activity. On the other hand, PAI-1 immunoreactivity was slightly inc reased at 10 mu g ml(-1) of saponin, but then was significantly decrea sed at 50 and 100 mu g ml(-1). Cell proliferation was only slightly en hanced by 1-100 mu g ml(-1) of saponin, but migration was significantl y enhanced by 10-100 mu ml(-1) in a dose-dependent manner. Moreover, s aponin stimulated wound healing with enhanced angiogenesis in vivo. 4 These results indicate that saponin stimulates tube formation mainly b y modifying the balance of protease/protease inhibitor secretion from HUVEC and enhancing the migration of HUVEC, and that it is effective i n vivo.