title: GDNF-treated acellular nerve graft promotes motoneuron axon regeneration after implantation into cervical root avulsed spinal cord.
abstract: It is well known that glial cell line-derived neurotrophic factor (GDNF) is a potent neurotrophic factor for motoneurons. We have previously shown that it greatly enhanced motoneuron survival and axon regeneration after implantation of peripheral nerve graft following spinal root avulsion.
  
  
  OBJECTIVE
  In the current study, we explore whether injection of GDNF promotes axon regeneration in decellularized nerve induced by repeated freeze-thaw cycles.
  
  
  METHODS
  We injected saline or GDNF into the decellularized nerve after root avulsion in adult Sprague-Dawley rats and assessed motoneuron axon regeneration and Schwann cell migration by retrograde labelling and immunohistochemistry.
  
  
  RESULTS
  We found that no axons were present in saline-treated acellular nerve whereas Schwann cells migrated into GDNF-treated acellular nerve grafts. We also found that Schwann cells migrated into the nerve grafts as early as 4 days after implantation, coinciding with the first appearance of regenerating axons in the grafts. Application of GDNF outside the graft did not induce Schwann cell infiltration nor axon regeneration into the graft. Application of pleiotrophin, a trophic factor which promotes axon regeneration but not Schwann cell migration, did not promote axon infiltration into acellular nerve graft.
  
  
  CONCLUSIONS
  We conclude that GDNF induced Schwann cell migration and axon regeneration into the acellular nerve graft. Our findings can be of potential clinical value to develop acellular nerve grafting for use in spinal root avulsion injuries.
authors.affiliation: Department of Anatomy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR.
authors.forename: T-H
authors.initials: TH
authors.lastname: Chu
authors.forename: L
authors.initials: L
authors.lastname: Wang
authors.forename: A
authors.initials: A
authors.lastname: Guo
authors.forename: V W-K
authors.initials: VW
authors.lastname: Chan
authors.forename: C W-M
authors.initials: CW
authors.lastname: Wong
authors.forename: W
authors.initials: W
authors.lastname: Wu
mesh_terms: D000818:Animals; D001369:Axons / Q000187:drug effects* / Q000473:pathology; D051100:Glial Cell Line-Derived Neurotrophic Factor / Q000494:pharmacology*; D008297:Male; D009046:Motor Neurons / Q000187:drug effects* / Q000378:metabolism; D009416:Nerve Regeneration / Q000187:drug effects*; D019635:Neurosurgical Procedures / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D012583:Schwann Cells / Q000187:drug effects* / Q000473:pathology; D013116:Spinal Cord / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D013126:Spinal Nerve Roots / Q000187:drug effects* / Q000293:injuries / Q000601:surgery; D016378:Tissue Transplantation
chemical_list: D051100:Glial Cell Line-Derived Neurotrophic Factor