We investigated whether lipid peroxidation might influence activation of the mitogen activated protein kinase (MAPK) extracellular regulated kinase (ERK1/2) and c-Jun N-terminal kinase (JNK) in neointimal hyperplasia induced by flow interruption of carotid artery in mice. C57/BL6 mice were subjected to a complete ligation of the left common carotid artery or to a sham ligation. Animals were randomized to receive either IRFI-042, a Vitamin E-like inhibitor of lipid peroxidation (20 mg/kg/i.p., immediately after artery occlusion) or its vehicle (1 ml/kg of a NaCl-DMSO solution). The extent of lipid peroxidation (investigated by the means of conjugated dienes levels) and JNK and ERK activation were evaluated by Western blot analysis after blood flow interruption. ICAM-1 expression in injured arteries was investigated 4 days after artery ligation by the means of reverse transcriptase polymerase chain reaction (RT-PCR) and quantification of the ICAM-1 protein levels. Morphometric analysis of the structural alteration caused by the disruption of the arterial blood flow was performed 4 weeks after surgery. Flow interruption in the carotid artery resulted at 10 min, following occlusion in a marked increase in conjugated dienes tissue levels (5.8+/-0.44 DeltaABS/mg protein), caused at 30 min after occlusion peak increase in both ERK1/2 (45+/-8 integrated intensity) and JNK (38+/-6 integrated intensity) activities, enhanced ICAM-1 expression (1.5+/-0.45 relative amount of ICAM-1 mRNA) and ICAM-1 protein levels (55+/-12 pg/mg protein) and produced a marked neointimal hyperplasia (mean intimal area=101+/-14 microm2). Injured arteries harvested from IRFI-042-treated mice had reduced conjugated dienes tissue levels (2.9+/-0.5 DeltaABS/mg protein), attenuated ERK1/2 (19+/-6 integrated intensity) and JNK (2.9+/-0.5 integrated intensity) activities, blunted ICAM-1 expression (0.38+/-0.1 relative amount of ICAM-1 mRNA) and protein levels (26+/-8 pg/mg protein) and decreased neointimal hyperplasia (mean intimal area=4.5+/-1.5 microm2). Our data indicate that ERK1/2 and JNK kinases play a crucial role in neointimal hyperplasia induced by flow cessation in the mouse carotid artery. Furthermore, the present data suggest that lipid peroxidation triggers ERK and JNK activation.