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
PNS (total saponins of Panax notognseng, PNS) has a clear effect and wide application prospect for cardiovascular diseases. At the same time, saponins have hemolytic properties, which are related to its molecular structure type and dosage. On one hand, this article summarizes the research progress of PNS in heart cerebrovascular pharmacology pharmacological in recent five years, a number of studies both in vitro and in vivo for overall body, organs, cells and molecules, show that PNS could improve myocardial and cerebral ischemia injury, and it has effects in resisting thrombosis, inflammation, oxidation, atherosclerosis, and modulating vascular endothelial cells function and improving the cerebral ischemia injury etc. On the other hand, the hemolysis effect of PNS is closely related to its molecular structure type and administrating dosage. Different structures bring about different hemolysis activities. Structure-activity relationship suggests that the length of sugar side chains attached to C-20 and the disaccharide connection mode on C-3 may influence the hemolysis activity of PNS. Within the dose range from 2.5 to 250 mg•L⁻¹, PNS has no hemolysis activity. However, PNS exhibits hemolytic properties at high concentrations(≥500 mg•L⁻¹). Based on the hemolytic or anti-hemolysis characteristics of saponins, and dose-response relationship, the rational clinical application of PNS can be guaranteed by controlling the ratio of hemolytic monosaponins in PNS and improving the hemolytic test method.
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.