Figure 4

Quercetin inhibits leptin-induced NFκB activation. (A) FITC immunofluorescence labeling showed the signal density was increased after 500 ng/mL leptin exposure as compared to control. Quercetin addition in leptin-induced HUVECs reduced the density of NFκβ. Panel 1 control HUVECs without leptin and quercetin; panel 2 without leptin, but with 125 μM quercetin; panel 3 with 500 ng/mL leptin, but without quercetin; panel 4 with 500 ng/mL leptin and 125 μM quercetin. (B) Western blot analysis of p65 NFκB in HUVECs confirmed the immunofluorescence labeling. L0Q0 control HUVECs without leptin and quercetin; L0Q125 without leptin, with 125 μM quercetin; L500Q0 with 500 ng/mL leptin, without quercetin; L500Q125 with 500 ng/mL leptin and 125 μM quercetin. (C) ELISA measurement showed a significant increased of NFκβ activation in leptin-induced HUVECs when compared to control, and quercetin administration significantly reduced the activated NFκB level. L0Q0 control HUVECs without leptin and quercetin; L0Q125 without leptin, but with 125 μM quercetin; L500Q0 with 500 ng/mL leptin, but without quercetin; L500Q125 with 500 ng/mL leptin and 125 μM quercetin. Means without a common letter differ, p < 0.001.