Effects of Ginkgo biloba extract on expressions of IL-1β, TNF-α, and IL-10 in U937 foam cells

This study is to investigate the protein and mRNA expressions of pro-inflammatory and anti-inflammatory cytokines in U937 foam cells and effects of Ginkgo biloba extract (GbE) on the cytokines. U937 cells were cultured with different concentrations of GbE (0.1, 1, and 10 μg·L^-1), and stimulated by 100 mg·L^-1 oxidized low density lipoprotein (ox-LDL) for 24 h. The expressions of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and interleukin-10 (IL-10) in culture solution were detected by enzyme-linked immunosorbant assay (ELISA) and reverse transcriptase polymerase chain reaction (RT-PCR). The results showed that incubated with 100 mg·L^-1 ox-LDL for 24 h, the U937 cells became foam cells, the protein or mRNA expressions of IL-1β, TNF-α, IL-10, and its receptor IL-10R in U937 foam cells were higher markedly than those in normal U937 cells. When the cells were pretreated with GbE (0.1, 1, and 10 μg·L^-1), the increases of IL-1β and TNF-α in U937 foam cells were remarkably inhibited, but IL-10 expression increased greatly. Especially when cells were pretreated with 10 μg·L^-1 GbE, the protein and mRNA expressions of IL-1β and TNF-α were markedly lower than those in U937 foam cells. The protein expression of IL-10 and mRNA expressions of IL-10 and its receptor IL-10R were markedly higher than those in U937 foam cells. GbE inhibited production of pro-inflammatory cytokines IL-1β and TNF-α, but up-regulated the production of anti-inflammatory cytokine IL-10 and its receptor IL-10R in U937 foam cells, which might be related with its anti-atherosclerotic actions.