OBJECTIVETo examine the effect of ginsenoside Rb1 (GRb1) on the immune maturation of monocyte-derived dendritic cells (DCs) induced by oxidized low-density lipoprotein (OX-LDL).

METHODSHuman monocytes purified by CD14+ immuno-magnetic beads were differentiated and induced into immature DCs, which were randomly divided into 6 groups, Group A treated with PBS, Group B treated with OX-LDL, Group C and D treated respectively with GRb1 and ciglitazone, Group E and F were pretreated with the two testing drugs respectively followed by OX-LDL. The immuno-phenotypic expression (CD40, CD1a, and HLA-DR) and endocytosis function of DCs were examined using flow cytometry, the concentration of interleukin-12 (IL-12) and tumor necrosis factor alpha (TNF-alpha) in the culture supernatants were measured with ELISA.

RESULTSCompared with Group B, Group E showed significantly lowered immuno-phenotypic expression of DCs in terms of CD40 (67.4 +/- 1.62 vs. 145.69 +/- 14.86), CD1a (79.64 +/- 3.04 vs. 159.89 +/- 6.09), and HLA-DR (46.43 +/- 2.85 vs. 99.33 +/- 17.11), as well as higher endocytosis level (88.13% +/- 1.06% vs. 25.90% +/- 5.77%, all P < 0.01). Meantime, the serum levels of IL-12 (88.65 +/- 5.59 ng/L vs. 716.69 +/- 36.35 ng/L) and TNF-alpha (133.27 +/- 11.98 ng/L vs. 968.10 +/- 36.42 ng/L) obviously decreased (P < 0.01). The surface molecular expression of DCs and the secretion of inflammatory factors in Group F also obviously decreased, showing insignificant difference from Group E (P > 0.05).

CONCLUSIONGRb1 could obviously inhibit the OX-LDL-induced maturation of DCs, showing similar effects to ciglitazone.