Neural Regeneration Flashcards Preview

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Flashcards in Neural Regeneration Deck (40):
1

central axon damaged what happens? 3 things

Retract processes
Sprouting possible
inhibited by glial scar

2

how does the PNS neuron look after nerve injury?

1. peripheral nucleus
2. loss of Nissl substance

3

what is chromolysis/chromatolysis?

loss of Nissl substance

4

What is Wallerian Degeneration?

degen of axon/myelin below injury, mopped up by Macrophages

5

3 weeks post injury to PNS what do you get?

schwann cells proliferate, compact cord

6

How fast do PNS axons regrow?

0.5-3mm/day

7

how long for successful regen in PNS since initial injury?

~3months

8

How does the regenned PNS nerve look compared to normal?

thinner sheath

9

what happens if you get unsuccessful PNS regen?

neuroma formation

10

Repair in PNS is faster when?

crushed vs. cut

11

main therapeutic approach to PNS injury?

microsurgery

12

oligodendrocytes and CNS regen do what?

inhibit regrowth

13

secondary damage minutes to hours in SCI include 5 things:

1. ischemia
2. Ca2+ influx
3. lipid peroxidation/free radicals
4. glutamate excitotoxicity
5. BBB break down

14

Treatment for SCI degenerative insults?

erythropoietin

15

Hours to days/weeks what happens in SCI? what happens? 3 things?

immune cells infiltrate
microglia activate
cytokines/chemokines released

16

what is a syrinx?

cavity formation for meningeal fibroblasts in SCI

17

What in the injury environment inhibits CNS regen? 2 big things things

astrocytic gliosis
Glial scar

18

4 things needed to repair CNS?

1. Neuroprotection
2. Axononal regen/functional integration
3. modulate astrocytic gliosis
4. neural stem cells

19

2 approaches to neural stem cells are?

1. mobilise endogenous cells
2. transplant exogenous cells

20

Another reason for lack of CNS regen besides injury environment?

lack of trophic support
no growth promoting factors

21

what is sprouting?

an adjacent nerve grows new processes to take over injured nerve's functions

22

Astrocytic gliosis does what?

increase GFAP
cytokines
extracelular matrix, proteogylcans
becomes glial scar = barrier to regen

23

research to prevent Astrocytic gliosis?

blocking extracellular matrix

24

what happens if you knock out astrocytes completely in an SCI?

no regen at all

25

approach for Astrocytic gliosis?

regulation
block inhibitors secreted by astrocytes

26

What is Nogo? treatments?

Myelin inhibitor
testing anti-Nogo

27

What are axon guidance molecules?

promote, repel or guid regrowing axons

28

What does Nogo receptors activate?

Rho signalling = inhibits axon regrowth

29

What are Eph/Ephrins?

possible axon guidance molecules

30

What does Rho kinase in SCIs do?

activates astrocytes inhibiting regrowth

31

CNA vs. PNS degen?

CNS: slow
PNS: quick

32

CNA vs. PNS nerve structure after injury?

CNS: destroyed
PNS: intact

33

Schwann cells do what to injured PNS?

supports axon regrowth

34

What are the two main regions of neural stem cells?

1. subventricular zone (lateral ventricle)
2. subgranular zone (hippocampus)

35

Problems with endogenous neural stem cells in SCIs? 4:

1. Proliferation
2. migration (blocked by inflamm/gliosis
3. differentiation
4. Survival

36

what are iPSC and ESC?

induced pluripotent stem cell
embryonic stem cell

37

what kind of therapy is likely for SCI Rx?

combination

38

How to help with functional regen?

physical therapy

39

3 myelin proteins are? what do they do?

Nogo
MAG: myelin-associated glycoprotein
OMcp: oligodendrocyte myelin glycoprotein
bind to NogoR = inhibit regen

40

name 4 kinds of upregulated axon guidance molecules:

1.semaphorins
2. tenascin
3. cell adhesion molecules (N-CAM, L1, N-Cadherin)
4. EphA4/ephrinA5