Regeneration in the mature N.S

Question 1

Classification of nerve injuries?

Answer 1

1. Neuropraxia (compression)
2. Axonotmesis
3. Neurotmesis

Question 2

What happens in a peripheral nerve injury- to the proximal axon and soma?

Answer 2

Reorganisation and re-expression of immature features- e.g tubulin

Question 3

What happens in the distal axon

Answer 3

Wallerian degeneration

Question 4

What happens when a muscle is denervated?

Answer 4

1. Muscle atrophy
2. AchR reversal to imamture isoform
3. MUSK increase

Question 5

What happens in peripheral nerve regeneration

Answer 5

1. Schwann cells proliferate
2. Formation of bands of bungner
3. Re-growth along dividing Schwann cells
4. Sprouting of intact axons

Question 6

What usually occurs following spinal cord injuries?

Answer 6

Sprouting
failed regeneration
degeneration

Question 7

What evidence is there that its myelin proteins to blame for poor CNS regeneration

Answer 7

CNS neurons avoid oligos in vitro
removing oligos improves regenration
auto-immunisation to myelin proteins= increases regenration
NOGO KO mice have decreased inhibition of regeneration
Anti NOGO improves regeneration in spinal cord

Question 8

What are the objections to NOGO causing failed regeneration?

Answer 8

1. Much myelin removes by macrophages

2. Regeneration poor in white matter too

Question 9

Why may glia be blamed?

Answer 9

Glia proliferate at lesions
form scars
attachment to jumbled astrocytes- impair regeneration?

Question 10

What are spinal cord bridges?

Answer 10

Scaffolding/tubes connecting broken nerves
can be biological/artificial
filled with GFs, ECM etc

Question 11

4 types of transplanted stem cells used to help regeneration

Answer 11

1. Foetal
2. hESC
3. Umbilical
4. autologus NS stem/ others

Question 12

What 2 diseases have foetal cells been used to try and treat

Answer 12

Parkinson’s- initially undesired side fx, conflicting results, new trials more promising
Huntington’s- poor success