title: Molecular Mechanism of the "Babysitter" Procedure for Nerve Regeneration and Muscle Preservation in Peripheral Nerve Repair in a Rat Model.
abstract: OBJECTIVE
  To investigate the molecular mechanism of nerve "babysitter" for nerve regeneration and muscle preservation in peripheral nerve repair.
  
  
  METHODS
  Eighty rats were equalized into 4 groups: peroneal nerve transected, group A received no treatment; group B underwent end-to-end repair; group C underwent end-to-side "babysitter" with donor epineurial window; group D underwent end-to-side "babysitter" with 40% donor neurectomy. During second-stage procedure, end-to-end neurorrhaphies were executed in groups A, C, and D. Expression of Insulin-like growth factor (IGF)-1 in spinal cord and IGF-1, TNF-like weak inducer of apoptosis (TWEAK), and Fn14 in anterior tibial muscles were evaluated by histopathology at 4-, 8-, 12-, and 24-week timepoints postoperatively.
  
  
  RESULTS
  At 4 weeks, group D expressed comparable IGF-1 with group B, and greater value than groups A and C in spinal cord. By 24 weeks, groups B and D showed higher values than groups A and C. Insulin-like growth factor 1 in muscles were greater in groups C and D than in groups A and B at 4 weeks, and comparable in all groups at 24 weeks. At 4 weeks, immunoreactive scores of TWEAK were 9.00 ± 0, 3.00 ± 0, 6.75 ± 0.75, and 6.75 ± 0.75, respectively. No differences were noticed in all groups by 24 weeks. At 4 weeks, Fn14 were similar in groups A, C, and D, but lower in group B. Group D showed comparable Fn14 with groups B and C, but lower value than group A at 24 weeks.
  
  
  CONCLUSIONS
  End-to-side nerve "babysitter" in peripheral nerve could promote fiber regeneration and muscle preservation by regulating expression of IGF-1 and TWEAK-Fn14. End-to-side "babysitter" with partial donor neurectomy could achieve comparable effects with end-to-end repair.
authors.affiliation: From the *Department of Orthopedic Surgery, the Affiliated Hospital of Qingdao University, Shandong; †Department of Orthopedic Surgery, Zhongshan Hospital, Fudan University, Shanghai, China; ‡Joseph M. Still Burn and Reconstructive Center; and §Division of Plastic Surgery, University of Mississippi Medical Center, Jackson, MS.
authors.forename: Hai-Fei
authors.initials: HF
authors.lastname: Liu
authors.forename: Zeng-Gan
authors.initials: ZG
authors.lastname: Chen
authors.forename: William C
authors.initials: WC
authors.lastname: Lineaweaver
authors.forename: Michael T
authors.initials: MT
authors.lastname: Friel
authors.forename: Feng
authors.initials: F
authors.lastname: Zhang
mesh_terms: D000818:Animals; D000074049:Cytokine TWEAK / Q000378:metabolism; D005260:Female; D007150:Immunohistochemistry; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D018482:Muscle, Skeletal / Q000294:innervation*; D009416:Nerve Regeneration / Q000502:physiology*; D019635:Neurosurgical Procedures / Q000379:methods*; D010543:Peroneal Nerve / Q000378:metabolism / Q000601:surgery*; D011897:Random Allocation; D051381:Rats; D011917:Rats, Inbred Lew; D000074050:TWEAK Receptor / Q000378:metabolism
chemical_list: D000074049:Cytokine TWEAK; D000074050:TWEAK Receptor; C000613300:Tnfrsf12a protein, rat; C497771:Tnfsf12 protein, rat; D007334:Insulin-Like Growth Factor I