OBJECTIVETo observe the effects of Modified Liangge Powder (MLP) on the expressions of platelet toll like receptor 4 (TLR4) and the release of platelet-derived cytokines interleukin 8 (IL-8), beta platelet globulin (beta-TG), soluble CD40 ligand (sCD40L).

METHODSThe modulating effects on the release of cytokines from mice platelets by TLR4 ligand through monoclonal antibody blocking TLR4 on platelet were compared. The stimulated platelet by LPS was incubated with low (0.94 g/mL), medium (1.89 g/mL), and high (2.84 g/mL) dose of MLP contained serum. The changes of the platelet TLR4 expression and platelet-derived cytokines were observed.

RESULTSThe positive expression rate of platelet TLR4 obviously decreased (P < 0.01) and the release of sCD40L and beta-TG from platelets significantly increased (P < 0.01) after stimulated by LPS. However, the release of sCD40L and beta-TG from platelets obviously decreased by TLR4 monoclonal antibody (P < 0.05, P < 0.01). There was no statistical difference in IL-8 between before and after LPS stimulation (P > 0.05). Platelet TLR4 positive expression rate was significantly higher after incubated by medium and high doses of MLP contained serum (P < 0.01), and the releasing of sCD40L and beta-TG was lower in the serum contained groups. The inhibitory effects were enhanced in a dose-dependent manner.

CONCLUSIONSLPS induced platelet activation by TLR4 and released sCD40L and beta-TG, while the release of platelet IL-8 was not dependent on platelet TLR4-LPS pathway. MLP could inhibit LPS-stimulated sCD40L and beta-TG, inhibit the binding of platelet TLR4 and LPS in a dose-dependent manner, thus reducing the release of platelet cytokines.