Neural Regeneration Flashcards
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?
Microsurgery
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?
Ischaemia
Ca++ influx
Lipid perioxidation and free radical production
BBB loss
Glutamate excitotoxicity
Do CNS or PNS nerve regenerate better?
PNS
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?
Bad
What forms at the resolution of CNS injury?
Glial scar
Astrocytic gliosis
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?
Hippocampus
Lateral Ventricle
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
2 weeks
