Fig. 1.
The effect of gintonin (GT) on the VEGF content of the media containing primary astrocytes. (A) Concentration-dependent stimulation of VEGF release by GT. Histograms generated from the results of treatment of primary astrocytes with 0.1–1 μg/mL GT (∗p < 0.01), compared to those of the untreated control (Con). The effect on the VEGF content after treatment with the LPA1/3 receptor antagonist (Ki16425, 10 μM) alone or a combination of Ki16425 (10 μM) and GT (0.3 μg/mL) (#p < 0.01), compared to that after treatment with 1 μg/mL GT. All the data are represented as the mean ± S.E.M. (n = 4–5). (B) Time-course of the effect of GT on VEGF release. Histograms showing the secretion of VEGF over time, following treatment with 1 μg/mL GT (∗p < 0.01) compared to that of the control (0 h). ∗∗p < 0.005 compared to control (Con). The data are represented as the mean ± S.E.M. (n = 4–5). (C) Bar graphs representing the inhibition of the signal transduction pathway mediating the GT-induced VEGF release. The LPA1/3 receptor antagonist (Ki16425, 10 μM), the PLC inhibitor (U73122, 5 μM), IP3 receptor antagonist (2-APB, 100 μM), and the intracellular Ca2+ chelator (BAPTA-AM, 50 μM) were separately added to the culture before treatment with GT (1 μg/mL). For comparison, the cells were also treated with LPA (1 μM) and ginsenosides Rb1 or Rg1 (30 μM each). ∗p < 0.01, ∗∗p < 0.005, compared to control; #p < 0.01, compared to treatment with GT (1 μg/mL). The data are represented as the mean ± S.E.M. (n = 4–5). The concentration of VEGF in each sample was determined using a VEGF assay kit, as described in “Materials and methods Section”.
LPA, lysophosphatidic acid; S.E.M., standard error of the mean; VEGF, vascular endothelial growth factor.