Ginkgo biloba extract and Aspirin synergistically attenuate activated platelet-induced ROS production and LOX-1 expression in human coronary artery endothelial cells

Aim: In the present study, we investigated whether the therapeutic dosages of Ginkgo biloba extract (EGb) and Aspirin (ASP) might synergistically suppress oxidative stress through regulating the expressions of LOX-1 and phosphorylated p38MAPK (p-p38MAPK) in human coronary artery endothelial cells (HCAECs) ex vivo. Methods: HCAECs were stressed with activated platelets (2 x 10(8)/ml) and followed by ASP (1, 2 or 5 mmol/l), EGb (4, 40 or 400 mu g/ml) and combinational (1 mmol/l ASP and 40 mu g/ml EGb) treatments in three groups for 12 h. Superoxide anion in FICAECs was measured with H2DCF-DA probe. The expressions of LOX-1 and p-p38MAPK were examined by Western blot. Results: After stimulation of activated platelets, intracellular superoxide anion was increased about 3folds in HCAECs. Both ASP and EGb reduced superoxide anion in HCAECs in a dosage dependent manner. Combinational administration of ASP and EGb showed synergistic effect. By Western blot analysis, we were able to show that activated platelets markedly enhanced the expressions of LOX-1 and p-p38MAPK. Both ASP and EGb only inhibited LOX-1 expression in a concentration-dependent manner, but not pp38MAPK. As expected, the combination of ASP and EGb markedly reduced not only the expression of LOX-1 but also the phosphorylation of. p38MAPK. Conclusions: Both EGb and ASP attenuate the oxidative stress of HCAECs stimulated by activated platelets ex vivo. It appears that the synergistic effect of EGb and ASP may correlate with the inhibition of ROS production, LOX-1 expression and p38MAPK phosphorylation. (C) 2012 Elsevier GmbH. All rights reserved.