ABSTRACT
To investigate the anti-platelet adhesive effect and possible mechanisms of Xueshuantong capsule (XST) under flow conditions. Human umbilical vein endothelial cells (HUVECs) and human platelets were employed as experimental materials, and TNF-α (20 μg•L⁻¹) was used to establish vascular endothelial cell injury models. In vivo flow conditions were simulated under controlled shear stress of 0.1 Pa and 0.9 Pa by Bioflux1000 assays accordingly. Anti-platelet adhesive effects of XST at 0.3 g•L⁻¹ were dynamically monitored by microscopic time-lapse photography. Western blotting was employed to detect the VCAM-1 expression on endothelial cells, and the release of 6-keto-PGF1α and TXB2 was tested by radioimmunoassay. The results showed that XST could inhibit the platelets adhesion under both physiological and pathological flow conditions, and the inhibition rate was 15.0% and 34.1% respectively. Under pathological low shear stress or static conditions, XST could significantly inhibit endothelial cells VCAM-1 expression and TXB2 release (P<0.05). These results suggested that XST inhibited platelets adhering to injured endothelium via decreasing VCAM-1 expression and TXA2 secretion from endothelium. From the interactions among blood flow, vascular endothelium and platelets, the anti-thrombosis effects of XST were possibly related to endothelial cells protection and therefore inhibiting platelets adhesion. Under different flow conditions, the antiplatelet adhesion effect of XST was different, and the pathological low shear stress was more conducive to the efficacy of XST.
ABSTRACT
A in vitro platelet aggregation bioassay was developed for the quality control of XST capsules. The in vitro anti-platelet aggregation effect in rats was observed to detect the bioactivity of XST capsules. Panax notoginseng saponins and Xuesaitong lyophilizedpowder for injection were taken as standard control substances to determine the potency. According to the results, XST capsules showeda significant inhibitory effect on thrombin-induced platelet aggregation in a dose-dependent manner. The in vitro anti-platelet activity oflyophilized powder for injection was stabler than that of Panax notoginseng saponins, and so suitable to serve as a standard control substance. The biological potency of XST capsules compared with standard control substance was detected by using parallel line assay. According to the results, the established bioassay method had a good repeatability (RSD 2.92%). The sample test results could pass thereliability test(linear deviation P > 0.05, parallel deviation P > 0.05). This bioassay method could be used as one of the complementary quality control methods for XST capsules.