Figure 4: AGEs could induce NO synthesis through RAGE-ERK and p38 signaling pathways. Effects of NF-κB, ERK, and P38 inhibitors on AGE-induced NO reduction. NO concentration of HUVEC culture supernatant was measured by a total NO assay kit. (a) The HUVECs were pretreated with medium, HSA, AGEs, and AGEs + anti-RAGE, respectively. (b) The HUVECs were pretreated with AGEs, AGEs + NF-κB inhibitor (helenalin), AGEs + p38 MAPK inhibitor (SB202190), and AGEs + ERK1/2 MAPK inhibitor (PD98059), respectively. AGEs: Advanced glycation end-products, RAGE: Receptor for advanced glycation end-products, HUVECs: Human umbilical venous endothelial cells, NF-κB: Nuclear factor-kappa B, MAPK: Mitogen-activated protein kinase, PCR: Polymerase chain reaction