OBJECTIVETo investigate the influence of Yiqi Huoxue Recipe (YHR) containing drug-serum on the expression of Toll-like receptor-4 (TLR4) and its downstream signaling components MyD88, as well as the tumor necrosis factor receptor related factor-6 (TRAF-6) in human vein endothelial cells (HUVECs) induced by lipopolysaccharide (LPS), and to study its possible anti-atherosclerotic mechanism from the gene and protein levels.

METHODSTwenty New Zealand male rabbits were equally divided into four groups in random: the normal control group and the three YHR groups, 5 in each group. They were gastric perfused daily with normal saline and YHR in low, moderate and high concentration respectively. Blood drawn from rabbits' heart 2 h after ending perfusion on the 7th day, and the serum separated (that is the drug-serum) was taken for testing. HUVECs were cultured in vitro and equally divided into six groups in random: the normal control group, the model group, the Western medicine group and the three YHR groups. HUVECs were stimulated with LPS, then treated separately with the drug-serum containing different concentrations of YHR for 24 h. Then the mRNA expressions of TLR4, MyD88 and TRAF-6 were measured with Real-time PCR, and their protein expressions were analyzed using Western blotting.

RESULTSProtein and mRNA expressions of TLR4, MyD88 and TRAF-6 increased significantly after LPS stimulation (P < 0.01), but the changes in the drug-serum treated groups were significantly lower than those in the saline control group respectively (P < 0.01 or P < 0.05).

CONCLUSIONYHR can block the high expression of TLR4, and also influence the MyD88-dependent signaling pathway of TLR4, suppress the downstream expression of NF-kappaB and various related gene expressions, which may be one of its mechanisms of action for anti-atherosclerosis.