Objective:To investigate the influence of Hydroxysafflor yellowA(HSYA)on the expression ofthrombospondin-(lTSP-1)in human aortic endothelial cells for a further study of the mechanism of hydroxysafflor yellow A inhibiting endothelial cells’proliferation and preventing the growth of tumor.Methods:We use the method of MTT to observe the proliferation of HAEC with the influence of HSYA.Real Time PCR and immunocytochemistry were used to detect the level of mRNA and protein of TSP-1 after HSYA’s effect.TSP-1 in the culture medium is assayed in the way of ELISA.Results:HSYA’s effect on proliferation of HAEC showed a concentration-depen dence

for higher concentration(>0.065 7 g/L)causing inhibition of the proliferation of HAEC while a lower concentration(<0.065 7g/L)arosing catalyst performance.HSYA promotes the expression of mRNA of TSP-1

and the effect is enhanced as the concentration increases.;The expression of TSP-1 is similar to the result of our RT-PCR.Conclusion:HSYA promotes the expression of TSP-1.The HSYA shows a two-way effect on the proliferation of endothelial cells

and regulating the expression of TSP-1and VEGF may be the main way to achieve it.The anti-tumor effect of HSYA may be through a way of promoting the expression of TSP-1 to inhibit the proliferation of endothelial cells and prevent angiogenesis.