Abstract: The objective of this experiment was to study the effect of Astragalus polysaccharin (APS) on adhesion of peripheral lymphocyte (PLC) and jugular vein endothelial cells (JVEC) in broiler. The JVEC and PLC of broiler were treated independently with four doses of APS (0,200,600 and 1000 μg/mL) and the adhesion changes of them were observed subsequently. Also the two types of cells were incubated with interleukin-1 (IL-1,1000 U/mL) or tumor necrosis factor-α (TNF-α,1000 U/mL) to investigate the effect of APS on intercellular adhesion and the regulatory mechanism of APS to intercellular cell adhesion molecule-1 (ICAM-1) and T-lymphocyte subsets CD4⁺.The results showed that the PLC-JVEC adhesion increased significantly when the JVEC was incubated with APS (600 μg/mL) (P<0.05).The same significant increment of intercellular adhesion was observed when the JVEC was incubated with the combination of IL-1 and APS (1000 μg/mL),or the PLC was incubated with the combination of IL-1 and APS (200,600 and 1000 μg/mL) (P<0.05).Compared with the control group,the PLC-JVEC adhesion increased significantly when the JVEC was incubated with the combination of TNF-α (P<0.05).Compared with the control group,the values of ICAM-1 and percentage of positive cell (CD4⁺) increased significantly with the combined treatment of IL-1 and high dose of APS (1000 μg/mL) (P<0.05).In conclusion,the dose of APS affected its regulation on PLC-JVEC adhesion. Under this experimental conditions,both the medium and high doses of APS (600 and 1000 μg/mL)could increase the PLC-JVEC adhesion alone or with the combination of IL-1 and TNF-α.At the same time,the high dose of APS (1000 μg/mL) could exert the immunomodulatory by changing the secretion (expression) of ICAM-1 and CD4⁺.

Key words: Astragalus polysaccharin (APS); broiler; intercellular cell adhesion molecule-1 (ICAM-1); T-lymphocyte subsets CD4⁺; immunomodulatory