Involvement of free radicals in neuropathic pain and the effect of the free radical scavenger

Abstract

We explored the possibility of local inflammation as the mechanism responsible for the chronic constriction injury (CCI) model. Local inflammation induces the release of several algogenic substances and causes pain. It is thought that nitric oxide (NO), a free radical, causes pain. We administered a free radical scavenger to a CCI model and analyzed the reactions of neuropathic pain through behavioral and histological studies. We divided the experimental model into group A, in which edaravone was administered at 15mg/kg/day, group B, in which it was administered at 5mg/kg/day, and group S, in which saline was administered. All substances were applied for a period of six days. We then used the Plantar test^[○!R] and a Dynamic Plantar Aesthesiometer^[○!R] to evaluate the degree of neuropathic pain. The Histological investigation of the occurrence of local changes was done using H-E staining. Evaluation of neuropathic pain using the behavior test showed no improvement in any of the groups. However, H-E staining showed no difference in the degree of increase in cell components. We found that the free radical scavenger did not inhibit neuropathic pain.