title: Optimal time window of myelotomy in rats with acute traumatic spinal cord injury: a preliminary study.
abstract: OBJECTIVE
  Pathophysiological mechanisms underlying spinal cord injury (SCI) partially involve edema and formation of a hematoma. Myelotomy seems to be a promising intervention. However, the appropriate timing of myelotomy is still unknown in SCI. Here we aimed to determine the timing of microsurgical myelotomy in an animal model of SCI.
  
  
  METHODS
  The SCI model was contusion-induced with a new york university impactor. Sixty-five adult female rats were randomly divided into the following groups: laminectomy alone (the 'sham group', SG), laminectomy plus contusion (the 'contusion group', CG) or laminectomy plus contusion followed by myelotomy at 8, 24 or 48 h (8 h-MTG [myelotomy-treated group], 24 h-MTG or 48 h-MTG). Functional recovery was evaluated via the open field test and the inclined plane test every week after SCI. The percentage of spared white matter area (SWMA) and ultrastructure characteristics of the injured dorsolateral spinal cord were determined on the 42nd day after SCI.
  
  
  RESULTS
  Compared with the CG, myelotomy at 8 h-MTG or 24 h-MTG greatly improved the BASSO-BEATTIE- BRESNAHAN scores (P<0.008), whereas the 48 h-MTG showed less efficacy (P=0.023). All myelotomy groups showed higher mean angle values in an inclined plane test (P<0.005) and had greater percentages of SWMA than the CG. Rats in the 24 h-MTG showed a higher intra-axonal fraction and myelin fraction than those in 48 h-MTG (P<0.005).
  
  
  CONCLUSIONS
  Myelotomy up to 48 h after SCI improves recovery in rats. The potential time window of myelotomy may be between 8 and 24 h after SCI.
authors.affiliation: School of Rehabilitation Medicine of Capital Medical University, Department of Spinal and Neural Function Reconstruction, China Rehabilitation Research Center, Beijing, People's Republic of China.
authors.forename: D-G
authors.initials: DG
authors.lastname: Yang
authors.forename: J-J
authors.initials: JJ
authors.lastname: Li
authors.forename: R
authors.initials: R
authors.lastname: Gu
authors.forename: M-L
authors.initials: ML
authors.lastname: Yang
authors.forename: X
authors.initials: X
authors.lastname: Zhang
authors.forename: L-J
authors.initials: LJ
authors.lastname: Du
authors.forename: W
authors.initials: W
authors.lastname: Sun
authors.forename: F
authors.initials: F
authors.lastname: Gao
authors.forename: A-M
authors.initials: AM
authors.lastname: Hu
authors.forename: Y-Y
authors.initials: YY
authors.lastname: Wu
authors.forename: J-G
authors.initials: JG
authors.lastname: He
authors.forename: Y-T
authors.initials: YT
authors.lastname: Feng
authors.forename: H-Y
authors.initials: HY
authors.lastname: Chu
mesh_terms: D000818:Animals; D001369:Axons / Q000473:pathology; D001522:Behavior, Animal / Q000502:physiology; D001812:Blood-Brain Barrier / Q000502:physiology; D007211:Indoles; D008124:Locomotion / Q000502:physiology; D008854:Microscopy, Electron; D061145:Microvascular Decompression Surgery / Q000379:methods*; D009186:Myelin Sheath / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D020127:Recovery of Function; D013119:Spinal Cord Injuries / Q000473:pathology / Q000523:psychology / Q000601:surgery*; D013997:Time Factors
chemical_list: D007211:Indoles; C018588:Luxol Fast Blue MBS