Figure 4

Effect of (−)-epigallocatechin gallate on lipopolysaccharide-induced monocyte adhesion to endothelial cells. (A) Human cerebral microvascular endothelial cells/D3 (hCMEC/D3) were pretreated with or without (−)-epigallocatechin gallate (EGCG) (25 μM) for 1 h prior to lipopolysaccharide (LPS) (100 ng/mL) treatment for an additional 6 h. Calcein-AM-labeled fresh monocytes were then added to hCMEC/D3 cell cultures and incubated for 15 minutes at 37°C. The fluorescence was measured at 494/517 nm and the actual numbers of adherent monocytes were determined by comparing a standard plate with known numbers of labeled monocytes. (B) hCMEC/D3 cells were treated with LPS at the indicated concentrations for 6 h, or EGCG (1, 5, 25 μM) for 7 h, or pretreated with EGCG (1, 5 or 25 μM) for 1 h followed by LPS treatment (100 ng/mL) for 6 h. Data are expressed as mean ± SD of three different experiments (*P < 0.05, **P < 0.01).