Role of chronic Schwann cell denervation in poor functional recovery after nerve injuries and experimental strategies to combat it

Neurosurgery. 2009 Oct;65(4 Suppl):A105-14. doi: 10.1227/01.NEU.0000358537.30354.63.


Objective: To present our data about the role of chronic denervation (CD) of the distal nerve stumps as compared with muscle denervation atrophy and experimental strategies to promote better functional recovery.

Methods: A rat model of nerve injury and repair was used. The common peroneal branch of the sciatic nerve was subjected to 0 to 24 weeks of CD before cross-suture with the tibial motoneurons. Our outcome measures included the numbers of motoneurons that regenerated their axons and the numbers that reinnervated muscle targets (motor units). To overcome the effects of CD, we used subcutaneous injection of FK506 and in vitro reactivation of Schwann cells that had been subjected to 24 weeks of CD with transforming growth factor beta.

Results: Numbers of regenerated motoneurons and reinnervated motor units decreased as a function of duration of CD. However, axons that regenerated through the distal nerve stumps reinnervated the muscle targets and even formed enlarged motor unit size regardless of the duration of CD. FK506 doubled the numbers of tibial motoneurons that regenerated their axons into the common peroneal nerve even after delayed repair. Reactivation of chronically denervated Schwann cells with transforming growth factor beta significantly increased their capacity to support axonal regeneration.

Conclusion: CD of the distal nerve stumps is the primary factor that results in poor axonal regeneration and subsequently poor functional recovery. Acceleration of the rate of axonal regeneration and/or reactivation of Schwann cells of the distal nerve stumps are effective experimental strategies to promote axonal regeneration and functional recovery.

Publication types

  • Review

MeSH terms

  • Animals
  • Denervation / adverse effects
  • Disease Models, Animal
  • Growth Cones / drug effects
  • Growth Cones / physiology
  • Immunosuppressive Agents / pharmacology
  • Immunosuppressive Agents / therapeutic use
  • Male
  • Nerve Regeneration / drug effects
  • Nerve Regeneration / physiology
  • Nerve Transfer / methods*
  • Rats
  • Recovery of Function / drug effects
  • Recovery of Function / physiology
  • Schwann Cells / cytology
  • Schwann Cells / physiology*
  • Sciatic Nerve / physiopathology
  • Sciatic Nerve / surgery*
  • Sciatic Neuropathy / physiopathology
  • Sciatic Neuropathy / surgery*
  • Tacrolimus / pharmacology
  • Tacrolimus / therapeutic use
  • Transforming Growth Factor beta / pharmacology
  • Transforming Growth Factor beta / therapeutic use


  • Immunosuppressive Agents
  • Transforming Growth Factor beta
  • Tacrolimus