title: Intrathecal administration of mesenchymal stem cells reduces the reactive oxygen species and pain behavior in neuropathic rats.
abstract: BACKGROUND
  Neuropathic pain induced by spinal or peripheral nerve injury is very resistant to common pain killers, nerve block, and other pain management approaches. Recently, several studies using stem cells suggested a new way to control the neuropatic pain. In this study, we used the spinal nerve L5 ligation (SNL) model to investigate whether intrathecal rat mesenchymal stem cells (rMSCs) were able to decrease pain behavior, as well as the relationship between rMSCs and reactive oxygen species (ROS).
  
  
  METHODS
  Neuropathic pain of the left hind paw was induced by unilateral SNL in Sprague-Dawley rats (n = 10 in each group). Mechanical sensitivity was assessed using Von Frey filaments at 3, 7, 10, 12, 14, 17, and 24 days post-ligation. rMSCs (10 µl, 1 × 10(5)) or phosphate buffer saline (PBS, 10 µl) was injected intrathecally at 7 days post-ligation. Dihydroethidium (DHE), an oxidative fluorescent dye, was used to detect ROS at 24 days post-ligation.
  
  
  RESULTS
  Tight ligation of the L5 spinal nerve induced allodynia in the left hind paw after 3 days post-ligation. ROS expression was increased significantly (P < 0.05) in spinal dorsal horn of L5. Intrathecal rMSCs significantly (P < 0.01) alleviated the allodynia at 10 days after intrathecal injection (17 days post-ligation). Intrathecal rMSCs administration significantly (P < 0.05) reduced ROS expression in the spinal dorsal horn.
  
  
  CONCLUSIONS
  These results suggest that rMSCs may modulate neuropathic pain generation through ROS expression after spinal nerve ligation.
authors.affiliation: Department of Anesthesiology and Pain Medicine, School of Medicine, Chungnam National University, Daejeon, Korea.
authors.forename: En Ji
authors.initials: EJ
authors.lastname: Zhang
authors.affiliation: Department of Microbiology, School of Medicine, Chungnam National University, Daejeon, Korea.
authors.forename: Chang Hwa
authors.initials: CH
authors.lastname: Song
authors.affiliation: Department of Anesthesiology and Pain Medicine, School of Medicine, Chungnam National University, Daejeon, Korea.
authors.forename: Young Kwon
authors.initials: YK
authors.lastname: Ko
authors.affiliation: Department of Anesthesiology and Pain Medicine, School of Medicine, Chungnam National University, Daejeon, Korea.
authors.forename: Won Hyung
authors.initials: WH
authors.lastname: Lee
keywords: mesenchymal stem cells; neuropathic pain; reactive oxygen species