To explore mechanisms of diabetes-associated vascular endothelial cells (ECs) injury, human umbilical vein ECs were treated for 24 h with high glucose (HG; 26 mM), advanced glycation end-products (AGEs; 100 mu g/ml) or their intermediate, glyoxal (GO: 50-5000 mu M). HG and AGEs had no effects on ECs morphology and inflammatory states as measured by vascular cell adhesion molecule (VCAM)-1 and cyclooxygenase (COX)-2 expressions. GO (500 mu M, 24 h) induced cytotoxic morphological changes and protein expression of COX-2 but not VCAM-1. GO (500 mu M, 24 h) activated ERK but not JNK, p38 or NF-kappa B. However, ERK inhibitor PD98059 was ineffective to GO-induced COX-2. While EUK134, synthetic combined superoxide dismutase/catalase mimetic, had no effect on GO-mediated inflammation, sodium nitroprusside inhibited it. The present results indicate that glyoxal, a metabolite of glucose might be a more powerful inducer for vascular ECs inflammatory injury. Nitric oxide but not anti-oxidant is preventive against GO-mediated inflammatory injury. (C) 2008 Elsevier Inc. All rights reserved.