Study regarding effects of the radical scavenger on ischemic-induced facial palsy

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The reactivation of herpes virus in the geniculate ganglion and the secondary microvascular disturbance of the facial nerve are essential for development of acute peripheral facial palsy. Especially, a vicious cycle of nerve edema and ischemia in the facial canal is essential for deterioration of palsy. Since ischemia is well known to promote free radical reactions, reactive oxygen species (ROS) is expected to play a crucial role in the development of palsy. In this study, we investigated the incidence of palsy, production of ROS, and histological findings after use of a radical scavenger, edaravone (Radicut・).1.The incidence of facial palsy53 Hartley guinea pigs served in this study and the petrosal branch of the middle meningeal artery was obstructed to cause ischemic facial palsy. Edaravone was given to 21 animals just after obstruction of the artery and to 12 animals 2 days after obstruction. The other 20 animals were not given edaravone as controls. The incidence of palsy in the a … More nimals treated early was remarkably low as compared to control animals and the incidence in late treated animals significantly decreased after administration of edaravone.2.Production of ROSROS was measured by dihydrotetramethyirosamine probe (Molecular Probes). The production of ROS was remarkable in the facial nerve of a non-treated animal, but it was nearly normal in the facial nerve of an edaravone-treated animal.3.Histological examination of facial nerve damageHistological changes of the facial nerve were investigated 1 month after artery damage in both treated and non-treated animals. The mastoid portion of the facial nerve showed severe damage in both groups but the geniculate ganglion in edaravone-treated animals showed preservation of cell bodies and findings of nerve regeneration whereas non-treated animals still revealed severe degeneration.In this study, edaravone attenuated development of ischemia-induced facial palsy in guinea pigs and prevented the production of ROS remarkably. In conclusion, the results lead that edaravone open the new avenue to the therapy of acute peripheral facial palsy. Less