title: Activation of neurotrophins in lumbar dorsal root probably contributes to neuropathic pain after spinal nerve ligation.
abstract: OBJECTIVE
  Neurotrophins (NTs) exert various effects on neuronal system. Growing evidence indicates that NTs are involved in the pathophysiology of neuropathic pain. However, the exact role of these proteins in modulating nociceptive signaling requires being defined. Thus, the aim of this study was to evaluate the effects of spinal nerve ligation (SNL) on NTs activation in the lumbar dorsal root.
  
  
  METHODS
  Ten male Wistar rats were randomly assigned to two groups: tight ligation of the L5 spinal nerve (SNL: n=5) and Sham (n=5). In order to produce neuropathic pain, the L5 spinal nerve was tightly ligated (SNL). Then, allodynia and hyperalgesia tests were conducted weekly. After 4 weeks, tissue samples were taken from the two groups for laboratory evaluations. Here, Real-Time PCR quantity method was used for measuring NTs gene expression levels.
  
  
  RESULTS
  SNL resulted in a significant weight loss in the soleus muscle (P<0.05), mechanical allodynia and thermal hyperalgesia thresholds (respectively,P<0.05;P<0.05). Also, NGF, NT-4, NT-3, TrkA, TrkB and TrkC expression were up-regulated following spinal nerve ligation group (respectively,P=0.025,P=0.013,P=0.001,P=0.002,P<0.001,P=001) (respectively, 4.7, 5.2, 7.5, 5.1, 7.2, 6.2 folds).
  
  
  CONCLUSIONS
  The present study provides new evidence that neuropathic pain induced by spinal nerve ligation probably activates NTs and Trk receptors expression in DRG. However, further studies are needed to better elucidate the role of NTs in a neuropathic pain.
authors.affiliation: Department of Physical Education and Sports Sciences, Faculty of Humanity and Literature, Vali E Asr University of Rafsanjan, Rafsanjan, Iran; Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran.
authors.forename: Abdolreza
authors.initials: A
authors.lastname: Kazemi
authors.affiliation: Departments of Physical Education and Sports Sciences, Lorestan University, Khoram Abad, Iran.
authors.forename: Masoud
authors.initials: M
authors.lastname: Rahmati
authors.affiliation: Department of corrective exercise and Sports injury, Faculty of Physical Education and Sports Sciences, Allameh Tabataba'i University, Tehran, Iran.
authors.forename: Rasoul
authors.initials: R
authors.lastname: Eslami
authors.affiliation: Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran.
authors.forename: Vahid
authors.initials: V
authors.lastname: Sheibani
keywords: Allodynia; Hyperalgesia; Neuropathic pain; Neurotrophins; Spinal nerve ligation