Page 127 - NNS 2014 Program & Abstract Book

at 24 h and 48 h after injury compared to sham while IL-1b expression
was significantly increased at 48 h, 72 h, and 1 week after injury
compared to sham. Moreover, partial purification of the pyroptosome
indicated by ASC laddering in the ipsilateral cortex suggests activation
of pyroptosis. In summary, this is the first report of inflammasome
activation in PBBI and suggests that pyroptosis occurs in conjunction
with previously characterized cell death mechanisms such as apoptosis,
thus leading to ipsilateral cortex tissue loss. Whether, pyroptosis plays a
more relevant role than apoptosis after PTBI is under investigation.
Key words
ballistic-like, brain injury, penetrating, traumatic
C3-17
DISTRIBUTION OF MICROGLIAL MORPHOLOGIES SHIFT
WITH THE BLOCKADE OF NOGO-66 RECEPTOR
Ziebell, J.M.1,2, Ray-Jones, H.F.1–3, Evilsizor, M.N.1,2, Adelson,
P.D.1,2, Lifshitz, J.1,2,4
1Barrow Neurological Institute at Phoenix Children’s Hospital,
Phoenix, USA
2Department of Child Health, University of Arizona, College of
Medicine, Phoenix, USA
3Department of Biology and Biochemistry, University of Bath, Bath,
UK
4Phoenix VA Healthcare System, Phoenix, USA
Diffuse traumatic brain injury (TBI) initiates secondary pathology, in-
cluding inflammation and dysmyelination. Considering these pathologies,
activated microglia would migrate through fields of growth-inhibitory
myelin byproduct, Nogo. We hypothesized that the Nogo-66 receptor
antagonist peptide NEP(1-40) would shift distributions of microglia
morphologies based on the environment permissiveness.
Adult male rats were subjected to midline fluid percussion sham- or
brain-injury. Animals received vehicle or drug (NEP(1-40), i.p.,
15 min and 19 h) and brains were collected at 2 h, 6 h, 1 d, 2 d and 7 d.
Immunohistochemistry for myelin (MBP; myelin basic protein and
CNPase), microglia morphology (Iba-1; ionized calcium binding
adapter protein), and Nogo was analyzed in sensory cortex.
Pronounced dysmyelination was evident at 1 d post-injury, as
evidenced by decreased MBP and CNPase staining, as well as loss of
white matter organization, compared to sham. Ramified microglia
were predominant in sham-injured cortex at all time points. Injury
shifted microglial morphology from ramified to activated as early as
2 h post-injury, regardless of treatment. NEP(1-40) administration
further shifted distributions of microglial morphologies to increased
rod morphology compared to vehicle-treated. Moreover, NEP(1-40)
increased proportions of macrophages from 2 h to 2 d post-injury. By
7 d post-injury, no differences in the distributions of microglia were
noted between vehicle and NEP(1-40).
This study begins to link white matter and inflammatory patholo-
gies after diffuse TBI. NEP(1-40) treatment shifted the distributions of
microglia morphologies, with an early increase in rod morphology.
The role of rod microglia is unknown, however, rods may provide
early stabilization to damaged neurons enabling restoration of circuits.
Therefore, the interaction between myelin-associated proteins and
microglia remains intriguing and encourages further investigation into
neuronal circuits and behavioral morbidities.
Supported, in part, by NIH NINDS R01NS065052 and PCH Mis-
sion Support Funds.
Key words
diffuse brain injury, microglia, nogo
C3-18
TIME COURSE OF MICROGLIA/MACROPHAGE ACTIVA-
TION AFTER TRAUMATIC BRAIN INJURY IN MICE
Caplan, H.W., Pavuluri, Y., Mandy, F., Mandy, F.J., Cox, C.S., Bedi,
S.S.
University of Texas, Health Science Center at Houston, Houston, USA
A major factor in the long-term outcome after Traumatic Brain Injury
(TBI) is a delayed, secondary inflammatory response within the CNS,
which is primarily mediated by microglia. In addition, there is infiltra-
tion of peripheral macrophages. Microglia/macrophages can be classi-
fied as non-activated (anti-inflammatory), activated (pro-inflammatory),
or slightly activated (those with morphologies in between). TBI
causes an increase in the activated microglia/macrophages popula-
tion and ratio of activated:non-activated within the brain. We hy-
pothesized that this change occurs between 24 and 72 hours after
injury and investigated differences between resident microglia and
infiltrating macrophages.
We used a Controlled Cortical Impact (CCI) device to administer a
unilateral injury to the temporal lobe of mice. Microglia/macrophages
were evaluated via immunohistochemistry using Iba1, a marker for
microglia/macrophages, and CD11c, a marker for myeloid dendritic
cells. Activation status was based on morphology of Iba1 + cells.
We observed an increase in the number and ratio of activated:
non-activated microglia/macrophages in the hippocampus at 72
hours in comparison to both the 24 hour and uninjured brains. At 24
and 72 hours, we observed marked co-labeling with Iba1 and
CD11c. In addition, we observed significant, chronic activation
of microglia/macrophages specifically in the ipsilateral thalamus at
28 days.
Our experiments demonstrated a dramatic increase in the activated
microglia/macrophage population within the hippocampus between 24
and 72 hours after initial injury, a decrease by 28 days, and chronic
activation in the ipsilateral thalamus at 28 days. However, we could
not definitively discern resident microglia from infiltrating macro-
phages using CD11c.
Key words
hippocampus, IBA1, microglia, thalamus
C3-19
SNTF IMMUNOHISTOCHEMISTRY IDENTIFIES A PRE-
VIOUSLY UNDETECTED POPULATION OF DEGENERAT-
ING AXONS FOLLOWING TRAUMATIC BRAIN INJURY
Johnson, V.E.1, Siman, R.1, Weber, M.T.1, Hay, J.2, Stewart, W.2,
Smith, D.H.1
1University of Pennsylvania, Dept. Neurosurgery, Philadelphia, USA
2Dept. Neuropathology, Southern General Hospital, Glasgow, UK
Up to 15% of patients with mild traumatic brain injury (mTBI) or
‘‘concussion’’ develop persistent, debilitating symptoms. While the
pathology of mTBI is largely unknown, diffuse axonal injury (DAI)
may be an important consequence of injury. A recent study indicates
that blood measurements of the calpain-cleaved alpha-II Spectrin N-
terminal fragment (SNTF) may be useful not only for the diagnosis of
mTBI, but in identifying patients that will have persisting neurocog-
nitive dysfunction. Here we examined the pathological basis of in-
creased serum-SNTF using both post-mortem cases of human TBI, as
well as a unique swine model of head rotational acceleration injury
(RAI) that induces DAI.
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