Effect of quercetin on adhesion of platelets to microvascular endothelial cells in vitro.

ABSTRACT

AIM: To study the effect of quercetin(Que) on the adhesion of platelets to microvascular endothelial cells (MVEC) isolated from human skin. METHODS: [3H]-adenine-labeled platelets were incubated with MVEC. Effect of Que on platelet endothelial cell adhesion molecular (PECAM) expression on MVEC was also evaluated using enzyme-linked immunosorbent assay (ELISA). RESULTS: Adhesion of platelet to MVEC reached to maximum at about 30 min. Que inhibited the adhesion of platelets to MVEC in a concentration-dependent manner. Que 5 micromol/L did not show any significant inhibition. When the concentration of Que increased to 10, 20, and 40 micromol/L, the inhibition rate increased to 10.5 %, 20.0 %, and 42.2 %, respectively. Pre-incubation of Que (10 - 40 micromol/L) with labeled platelets for 30 min also inhibited the adhesion but Que 5 micromol/L did not. The inhibition rate of Que 10, 20, and 40 micromol/L was 18.2 %, 29.8 %, and 65.3 % respectively. Expression of PECAM on the endothelial cells was decreased in a concentration-dependent manner when MVEC were treated with Que (10 - 40 micromol/L) for 12 h but Que 5 micromol/L did not significantly affect the expression. CONCLUSION: Que could inhibit the adhesion of platelets to MVEC. This effect may be related to decreased expression of PECAM on MVEC.