The effect of locally applied ngf and anti-NGF in experimental neuropathic pain model

THE EFFECT OF LOCALLY APPLIED NGF AND ANTI-NGF INEXPERIMENTAL NEUROPATHIC PAIN MODEL2. ABSTRACTSeveral pathophsiological mechanisms have been determined for the neuropathicpain resulting from damage and/or dysfunction of the any part of nervous system. NGFdo have an important role in neuropathic pain mechanisms. In this study we aimed toinvestigate the effects of locally applied NGF and anti-NGF in experimentalneuropathic pain model.Upon local ethic commitee approval, 24 Wistar albino rats, weighting about200-250 g, were set in this study. Wistar albino rats were randomly divided into fourgroups. Mechanothermal basal pain thresholds of the rats were measured in initial dayof the experiment. CCI model was applied to SF, NGF and anti-NGF groups whilesurgical procedure wasn?t applied to control group. Neuropathic process was evaluatedin SF, NGF and anti-NGF groups in the following days. Neuropathy was determined inthe postoperative 21st. day. Following this procedure saline was applied locally todamaged region of the rats in SF group for 28 days while any drug wasn?t applied tocontrol group. Local NGF solution (0.75 nanogram/gr =150 nanogram ) was applied todamaged hindpaw of the rats in NGF group for 28 days. Local anti-NGF solution (90picogram/gram =18 nanogram ) was applied to damaged hindpaw of the rats in anti-NGF group for 28 days. All groups? mechanothermal pain thresholds were recordedsince 21st. day for each subject.It has been noted that locally applied NGF increased mechanical and thermal(heat and cold) hyperalgesia due to neuropathic injury, in postop. Days 24-35, 23-30and 25-33. respectively. Moreover locally applied anti-NGF blocked mechanical andthermal (heat and cold) hyperalgesia due to neuropathic injury in postop. Days 24-35,25-32 and 27-31. respectively. However saline did not have any effect on hyperalgesicresponse.In conclusion; locally applied NGF increase of mechanical and thermalhyperalgesic response due to its nociceptive effect. In this study these data weresupported by antinociceptive effect of anti-NGF. We assume that neuroprotective andregulatory effect of NGF, which has been proved in previous studies is playing role ofthese results.Key Words: Neuropathic pain, NGF, anti-NGF, hyperalgesia