title: Axonal remodeling of the corticospinal tract in the spinal cord contributes to voluntary motor recovery after stroke in adult mice.
abstract: OBJECTIVE
  We sought to demonstrate the contribution of axonal remodeling of the corticospinal tract (CST) in the spinal cord to functional outcome after stroke.
  
  
  METHODS
  Bilateral pyramidotomy (BPT) or sham-BPT was performed in mice with transgenic yellow fluorescent protein labeling in the CST subjected to middle cerebral artery occlusion (MCAo). Foot-fault and single pellet reaching tests were performed 3 days after MCAo and weekly thereafter. Mice were euthanized at day 14 or 28 after stroke. Immunofluorescent staining for growth-associated protein-43 and Synaptophysin was performed on cervical sections.
  
  
  RESULTS
  Functional improvements were evident during the initial 14 days in both MCAo-sham-BPT and MCAo-BPT mice (P<0.01, versus day 3). Progressive recovery was present during the subsequent 14 days in MCAo-sham-BPT mice (P<0.001, versus day 14) but not in MCAo-BPT mice. In the stroke-affected cervical gray matter of MCAo-sham-BPT mice, growth-associated protein-43-Cy3 staining on CST axons were significantly increased at day 14 after stroke compared with normal mice (P<0.001), and CST axonal density and Synaptophysin-Cy3 staining of CST-yellow fluorescent protein axonal terminals were significantly increased at day 28 compared with day 14 after MCAo (P<0.001).
  
  
  CONCLUSIONS
  Our data demonstrate that voluntary motor recovery is associated with CST axonal outgrowth and synaptic formation in the denervated side of the spinal gray matter during the later phase after stroke, suggesting that the CST axonal plasticity in the spinal cord contributes to neurological recovery.
authors.affiliation: Department of Neurology, Henry Ford Hospital, Detroit, MI 48202, USA.
authors.forename: Zhongwu
authors.initials: Z
authors.lastname: Liu
authors.forename: Michael
authors.initials: M
authors.lastname: Chopp
authors.forename: Xiaoshuang
authors.initials: X
authors.lastname: Ding
authors.forename: Yisheng
authors.initials: Y
authors.lastname: Cui
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
mesh_terms: D000818:Animals; D001369:Axons / Q000502:physiology*; D004195:Disease Models, Animal; D019922:GAP-43 Protein / Q000737:chemistry; D020244:Infarction, Middle Cerebral Artery / Q000209:etiology / Q000503:physiopathology*; D051379:Mice; D008822:Mice, Transgenic; D009043:Motor Activity / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology; D011712:Pyramidal Tracts / Q000293:injuries / Q000473:pathology / Q000503:physiopathology*; D011897:Random Allocation; D020127:Recovery of Function / Q000502:physiology*; D016708:Synaptophysin / Q000737:chemistry; D013997:Time Factors
chemical_list: D019922:GAP-43 Protein; D016708:Synaptophysin
keywords: functional recovery; middle cerebral artery occlusion; neuronal plasticity; pyramidotomy