Nerve Regeneration

=Objectives=

Define how these factors influence neuron regeneration

 * Brain-derived Neurotrophic Factors (BDNF)
 * Promotes axonal outgrowth, trophic factor, protects neurons from apoptosis


 * Chondroitin Sulfate Proteoglycan (CSPG)
 * sulfated proteoglycans inhibit axonal outgrowth; chondroitinase promotes regrowth


 * NOGO
 * "No Go" is aptly named, as it inhibits axon pathfinding


 * Myelin-Associated Glycoprotein (MAG)
 * it's an inhibitor!


 * Immunophillin-Receptor Ligands (eg FK506)
 * Immunosuppressive drugs increase axonal growth independent of their antiiflammatory effects (not clinically useful, though).


 * Schwann Cell Basal Lamina
 * Schwann cell tracts provide signally clue to advancing neurons, so they have a positive effect on regrowth. Clinically useful for nerve grafting.

State why it's harder to repair a proximal axonal transection than a distal axonal compression

 * Proximal axonal transection (i.e., neurotmesis) involves disruption of the axon and basal lamina, which requires a nerve graft to replace schwann cells and basal lamina. Surgical grafting can mismatch the cables, leading to axonal misdirection (ie motor axon to sensory neuron).


 * Conversely, distal axonal compression (i.e., neurapraxia) most likely involves demyelination with no damage to the axon or basal lamina. No treatment is required and complete recovery is expected in a few days to weeks.


 * In the event that distal axonal compression is severe enough to injure the axon (i.e., axonotmesis) without rupturing basal lamina, physical therapy is indicated and recovery time will likely be longer (days = distance (mm) to target)

=References=