Neuroprotective effects of lycopene pretreatment on transient global cerebral ischemia­reperfusion in rats: The role of the Nrf2/HO­1 signaling pathway.

The present study aimed to investigate the neuroprotective effect of lycopene in a mouse model of bilateral common carotid artery occlusion (BCCAO) and the role of the Nrf2/HO­1 signaling pathway. A total of 60 male C57BL/6 mice, aged 12 weeks and weighing 20­24 g, were used in the present study. The mice were randomly assigned to three groups: Control, BCCAO and BCCAO + lycopene. The neurological score was assessed 24, 48 or 72 h following BCCAO. Hematoxylin and eosin staining, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) were performed to detect neuronal death and survival. The production of glutathione (GSH) and reactive oxygen species were detected to investigate the oxidative stress. The expression levels of nuclear factor erythroid 2­related factor (Nrf2) and Heme oxygenase­1 (HO­1) were determined by western blotting. Lycopene significantly improved the neurological score in the BCCAO mice. It attenuated neuronal apoptosis, as indicated by TUNEL staining, and attenuated the oxidative stress induced by global ischemia. Lycopene increased the expression levels of Nrf2 and HO­1, indicating that the Nrf2/HO­1 signaling pathway may be involved in the neuroprotective effect of lycopene. The present study revealed that lycopene protects the brain from global ischemic injury, which is associated with its antiapoptotic effect and the activation of the Nrf2/HO­1 signaling pathway.