P-83 - Effect of Luehea divaricata aqueous extract on superoxide anion formation in spinal cord of rats with neuropathic pain

Abstract

Superoxide anion (O2•-), a reactive oxygen species, plays an important role in neuropathic pain resulting from nerve tissue injury. Aqueous extract of leaves of Luehea divaricata has antioxidant compounds in its composition and exerts a neuroprotective effect. Because antioxidants appear as an alternative in treatment of neuropathic pain, we investigated the effect of an aqueous extract of leaves of Luehea divaricate on the formation of O2•- in the lumbosacral spinal cord of rats with chronic constriction injury (CCI) of the sciatic nerve, a model of neuropathic pain. We also measured the hepatic glutathione-S-transferase (GST) activity, because this enzyme plays an important role in detoxification of xenobiotics. von Frey electronic test was performed to assess the mechanical threshold before the surgery and 3, 5, 7 and 10 days after it. The extract attenuated the reduction in the mechanical threshold induced by CCI. The treatment also prevented the increase in O2•- formation induced by CCI by around 50%. No significant change was found in GST activity. The preventive effect on O2•- formation may be related to extract-induced antinociception, since scavenging of reactive oxygen species seems to help normalize the spinal cord oxidative status altered by pain.