Figure 5. Anti-inflammatory activity of APC derivatives using cellular assays. The anti-inflammatory activity of different concentrations of APC derivatives was assessed using four cellular assays as described in the “Methods” section. All results are presented as means ± SD of three different experiments. The significance level, *P < 0.05, **P < 0.01 and ***P < 0.001, represents differences in the APC-DEL group compared to the APC-WT group. (A) Protective effects of APC-WT and APC-DEL on the endothelial cell permeability in response to LPS. The permeability was determined spectrophotometrically at 650 nm. (B) Effects of APC-WT and APC-DEL on LPS-induced expression of cell adhesion molecules, ICAM-1, VCAM-1, and E-selectin, on the surface of endothelial cells. The expression was measured using an ELISA kit and detected at 450 nm. (C) The inhibitory effect of APC-WT and APC-DEL on the adherence of THP-1 cells to LPS-activated endothelial cells. The percentage of adherent THP-1 cells was calculated using the following formula: % adherence = (adherent signal/total signal) x 100. (D) The inhibitory effect of APC-WT and APC-DEL on LPS-induced NF-κB activation. The degree of activation of NF-κB was measured using an ELISA kit and detected at 450 nm.