title: The neuroprotective effect of erythropoietin on spinal motor neurons after nerve root avulsion injury in rats.
abstract: OBJECTIVE
  The rapid death of many spinal motor neurons after nerve root avulsion injury results in limited functional recovery following replantation surgery of avulsed nerves into the spinal cord. Therefore, we investigated the neuroprotective effect of erythropoietin (EPO) on motor neurons after nerve root avulsion injury using a rat model.
  
  
  METHODS
  After C6 nerve root avulsion injury, EPO (2680 U/kg) was injected subcutaneously once a day for 3 consecutive days with various starting time points. At 28 and 56 days after injury, histological and immunohistological investigations were performed.
  
  
  RESULTS
  EPO-treated rats showed a significant increase in the number of surviving motor neurons at day 28 when the initial dose was started within 96 h after injury. In EPO-treated rats, superoxide formation in the motor neurons and proliferation of microglia were markedly suppressed in the acute phase. GAP-43-positive surviving motor neurons were significantly increased in EPO-treated rats at day 28. However, at 56 days after surgery, EPO-treated rats showed a much greater decrease of surviving motor neurons compared with those at day 28.
  
  
  CONCLUSIONS
  The neuroprotective effect of EPO is not long lasting, but may prolong the time before replantation surgery.
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Noguchi
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Souichi
authors.initials: S
authors.lastname: Ohta
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Medicine, Kindai University, Osaka, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Kakinoki
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Ikeguchi
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Yukitoshi
authors.initials: Y
authors.lastname: Kaizawa
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Oda
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Shuichi
authors.initials: S
authors.lastname: Matsuda
mesh_terms: D000208:Acute Disease; D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D002574:Cervical Vertebrae; D002908:Chronic Disease; D004195:Disease Models, Animal; D004921:Erythropoietin / Q000008:administration & dosage*; D007279:Injections, Subcutaneous; D008297:Male; D017628:Microglia / Q000187:drug effects / Q000473:pathology / Q000502:physiology; D009046:Motor Neurons / Q000187:drug effects* / Q000473:pathology / Q000502:physiology; D009416:Nerve Regeneration / Q000187:drug effects / Q000502:physiology; D018696:Neuroprotective Agents / Q000008:administration & dosage*; D011843:Radiculopathy / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D011897:Random Allocation; D017207:Rats, Sprague-Dawley; D017467:Receptors, Erythropoietin / Q000378:metabolism; D013116:Spinal Cord / Q000187:drug effects* / Q000473:pathology / Q000503:physiopathology; D013481:Superoxides / Q000378:metabolism; D016896:Treatment Outcome
chemical_list: D018696:Neuroprotective Agents; D017467:Receptors, Erythropoietin; D013481:Superoxides; D004921:Erythropoietin
keywords: Nerve root avulsion injury; erythropoietin; motor neurons; oxidative stress; rat