What is the difference between axonal sprouting and regeneration?
Sprouting is when an existing axon produces a new synaptic process
Regeneration is the complete regrowth of a former axon
What do myelin inhibitors do?
Bind to regrowing axons and inhibit regrowth
How can you treat PNS nerve injury?
What occurs 3 weeks post injury in PNS nerves?
Schwann cell proliferation - produce good environment for nerve growth
New nerve fibres grow downstream and attempt to reattach
What occurs minutes to hours after CNS injury?
Lipid perioxidation and free radical production
Do CNS or PNS nerve regenerate better?
What occurs in PNS nerves if regeneration isn't successful?
Neuroma formation - bundle of nerve fibres that can be quite painful
Is the immune response good or bad in CNS injury?
What forms at the resolution of CNS injury?
Syrinx (cavity) formation
How does astrocytic gliosis affect axon regeneration?
Generally impedes regeneration and in the worst case can lead to glial scar formation that blocks neuronal regeneration
Can you completely inhibit astrocytic gliosis as a means of allowing repair?
No, it still performs an important function: BBB regeneration, wound sealing, growth factors etc
How can you treat a CNS injury?
Remove the source to prevent further injury
What are the two site of stem cell reservoir in the CNS?
What are the two factors that prevent CNS neuronal regeneration?
Lack trophic support
Axon regrowth is inhibited by the injury environment
What is Wallerian degeneration? When does it occur?
Degeneration of axon and myelin sheath post injury
Phagocytosis of debris by macrophages
How do neuronal cell bodies appear 2 weeks after injury?
Loss of Nissl bodies aka chromolysis
Nucleus moves peripheral
Why do crush injuries repair faster than lacerations?
The structure of the Schwann cells and matrix is retained so they guide repair
What is the cause of secondary injury that occurs in the hours/days/weeks after CNS injury?
The inflammatory immune response
How long does it take for successful regeneration of axon after damage?
What specific damage does the inflammatory immune response cause at the site of CNS injury?
Apoptosis of neurons and glials cells