Sequel to the death of oligodendrocytes trigged by
glutamate excitotoxicity and exacerbated by a cascade
that include; apoptosis, free radical assaults, activities
of pro-inflammatory/inflammatory mediator and
cytokines, is the demyelination of axons that survive
the initial trauma. Demyelination is due to loss of oligodendrocytes,
which are destroyed at the injury epicenter
within hours of the injury and continue to
undergo apoptosis in rostral and caudal white matter
for many weeks after SCI (Cash et al. 2001, Grossman
et al. 2001). This pathological process is particularly
evident in the sub- acute and chronic phases of SCI
(Guest et al.2005, Liverman et al. 2005). With the loss
of myelin, axons are now directly exposed to the damaging
effects of free radicals and inflammatory cytokines,
leading to neuronal loss via necrosis or/and apoptosis.
Demyelination leads to conduction delays or/and
conduction block (McTigue 2008, Hall and Traystman
2009). Given that axons traversing the injury site are
the sole remaining connection between the brain and
caudal spinal neurons, inefficient communication
through these axons is a significant clinical issue
(McTigue 2008). Hence demyelination and neuronal
loss sequel to oligodendrocytes death aggravates the
damage in a traumatized cord and thus limiting the
potentials for a cure.