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

AIM: To study the effect of quercetin(Que) on the adhesion of platelets to microvascular endothelial cells (MVEC) isolated from human skin. METHODS: [ H-3]-adenine-labeled platelets were incubated with MVEC. Effect of Que on p latelet endothelial cell adhesion molecular (PECAM) expression on NIVEC was also evaluated using enzyme-linked immunosorbent assay (ELISA). RESULTS: A dhesion of platelet to MVEC reached to maximum at about 30 min. Que inhibit ed the adhesion of platelets to MVEC in a concentration-dependent manner. Q ue 5 mu mol/L did not show any significant inhibition. When the concentrati on of Que increased to 10, 20, and 40 mu mol/L, the inhibition rate increas ed to 10.5 %, 20.0 %, and 42.2 %, respectively. Pre-incubation of Que (10 - 40 mu mol/L) with labeled platelets for 30 min also inhibited the adhesion ut Que 5 mu mol/L did not. The inhibition rate of Que 10, 20, and 40 mu mo l/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 M VEC were treated with Que (10 - 40 mu mol/L) for 12 h but Que 5 mu mol/L di d not significantly affect the expression. CONCLUSION: Que could inhibit th e adhesion of platelets to MVEC. This effect may be related to decreased ex pression of PECAM on MVEC.