Requirement of myeloid cells for axon regeneration

J Neurosci. 2008 Sep 17;28(38):9363-76. doi: 10.1523/JNEUROSCI.1447-08.2008.


The role of CD11b+ myeloid cells in axonal regeneration was assessed using axonal injury models and CD11b-TK(mt-30) mice expressing a mutated HSV-1 thymidine kinase (TK) gene regulated by the myeloid-specific CD11b promoter. Continuous delivery of ganciclovir at a sciatic nerve lesion site greatly decreased the number of granulocytes/inflammatory monocytes and macrophages in the distal stump of CD11b-TK(mt-30) mice. Axonal regeneration and locomotor function recovery were severely compromised in ganciclovir-treated CD11b-TK(mt-30) mice. This was caused by an unsuitable growth environment rather than an altered regeneration capacity of neurons. In absence of CD11b+ cells, the clearance of inhibitory myelin debris was prevented, neurotrophin synthesis was abolished, and blood vessel formation/maintenance was severely compromised in the sciatic nerve distal stump. Spinal cord-injured axons also failed to regenerate through peripheral nerve grafts in the absence of CD11b+ cells. Therefore, myeloid cells support axonal regeneration and functional recovery by creating a growth-permissive milieu for injured axons.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antiviral Agents / pharmacology
  • CD11 Antigens / immunology*
  • Cells, Cultured
  • Disease Models, Animal
  • Female
  • Ganciclovir / pharmacology
  • Graft Survival / physiology
  • Granulocytes / drug effects
  • Granulocytes / immunology
  • Growth Cones / immunology*
  • Growth Cones / metabolism
  • Macrophages / drug effects
  • Macrophages / immunology
  • Mice
  • Mice, Knockout
  • Mice, Transgenic
  • Monocytes / drug effects
  • Monocytes / immunology
  • Motor Activity / drug effects
  • Motor Activity / physiology
  • Myeloid Cells / immunology*
  • Nerve Regeneration / immunology*
  • Recovery of Function / drug effects
  • Recovery of Function / physiology
  • Sciatic Neuropathy / immunology
  • Sciatic Neuropathy / physiopathology
  • Thymidine Kinase / genetics
  • Thymidine Kinase / immunology
  • Tissue Transplantation


  • Antiviral Agents
  • CD11 Antigens
  • Thymidine Kinase
  • Ganciclovir