Transcript chapter_4 - Elsevier

Figure 4.6 Summary of events that occur
after mammalian spinal cord injury. The
primary damage is caused by compression
due to trauma and swelling of the cord
that impedes blood flow and kills neurons
by oxygen and glucose deprivation. A
second cause of primary damage is the
apoptosis of undamaged neurons that
overproduce the neurotransmitter
glutamate (g) and cause glutamate
excitotoxicity, which kills by opening
calcium channels, allowing massive influx
of extracellular calcium. Damaged and
undamaged neurons undergo
demyelination, forming myelin breakdown
products that cause growth cone collapse
(1). Chondroitin sulfate proteoglycans
(CSPGs) produced by astrocytes
contribute to growth cone collapse as
well. An inflammatory response is
initiated in which microglia express
inflammatory cytokines and bacteria and
cellular debris is cleared by macrophages
attracted by PDGF and TGF-β released by
platelets, creating cavities surrounded by
scar tissue in the cord (2).
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