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ultrastructural changes consistent with phagocytosis. This is the first study
to show direct physical correlation between the acute phase proximal
axonal swellings and non-phagocytic neuroinflammation in a higher order
animal. These findings could lead to a more complete understanding of
acute neuroinflammation following MTBI and its potential as a diagnostic
and/or a therapeutic target. This work was performed as a component of
the Operation Brain Trauma Therapy consortium, which is supported by
DoD grant W81XWH-10-1-0623.
Keywords: Neuroinflammation, Diffuse axonal injury, Micropig,
Central fluid percussion injury, Quantitative image analysis
S10-05
CHARACTERIZATION OF ENDOGENOUS BRAIN-DERIVED
NEUROTROPHIC FACTOR EXPRESSION IN RESPONSE TO
PENETRATING BALLISTIC-LIKE INJURY
Ying Deng-Bryant
, Sindhu Kizhakke Madathil, Lai Yee Leung,
Zhilin Liao, Frank Tortella, Deborah Shear
Walter Reed Army Institute of Research, Center for Military Psy-
chiatry and Neuroscience, Silver Spring, USA
Brain-derived neurotrophic factor (BDNF) has been shown to play a key
role in mediating neurogenesis and synaptic plasticity in the adult central
nervous system. However, little is known about the changes in this en-
dogenous molecule following penetrating ballistic-like injury (PBBI).
The aim of this study was to identify the regional and temporal alterations
in BDNF levels in relationship to downstream neuroplasticity markers in
the PBBI model. Adult male Sprague-Dawley rats received either sham
(craniotomy only) or PBBI (10% injury severity) surgery, and were eu-
thanized at 24h, 48h, 72h, and 7 days post-injury for BDNF quantifica-
tion, and at 7, 14 and 28d post-injury for neuroplasticity assessments
(n
=
5–6/time-point). BDNF levels were quantified in hippocampus and
cerebral cortex by ELISA assay, and growth-associated protein-43
(GAP-43) and synaptophysin (SYN) immunohistochemistry was per-
formed to assess axonal and synaptic plasticity, respectively. Following
immunostaining, the integrated density in the hippocampal region was
determined using NIH Image J software. Results showed significant re-
ductions in BDNF levels that were detected bilaterally in cortical and
hippocampal regions at 7 days post-injury (p
<
0.05 vs. sham), but not at
the earlier time points. PBBI significantly decreased GAP-43 expression
in the ipsilateral hippocampus at 14d and 28d post-injury, and in the
contralateral hippocampus at 14d post-injury (p
<
0.05 vs. sham). Simi-
larly, significant reductions in SYN staining were detected at 14d and 28d
post-injury in the ipsilateral hippocampus and at 14d post-injury in the
contralateral hippocampus (p
<
0.05 vs. sham). Collectively, these find-
ings demonstrate that PBBI results in a delayed down-regulation of
BDNF levels that precede subsequent reductions in neuroplasticity
markers. These results suggest a critical role of BDNF in modulating
endogenous neuroplastic response to brain injuries, underscoring the
potential importance of supplementing growth factors to enhance neu-
roplasticity for promoting functional recovery after PBBI.
Keywords: BDNF, Synaptophysin, GAP-43, PBBI
S11 Open Communication: SCI
S11-01
THE CGRP8-37 RECOMBINANT PEPTIDE CONSTRUCT TO
REDUCE CHRONIC PAIN FROM RAT SPINAL CORD INJURY
Chenxu Han
1
, Pingping Chen
2
, Chelsea Cosner
2
, Stanislava Jergova
2
,
Shyam Gajavelli
2
, Jacqueline Sagen
2
1
Florida International University, Biomedical Engineering, Miami,
USA
2
University of Miami, Neurosurgery, Miami, USA
Chronic pain following spinal cord injury (SCI) is challenging clinical
problem with few effective treatments. It is necessary to identify new
therapeutic targets and approaches. Calcitonin gene related peptide
(CGRP) is produced by neurons in the dorsal root ganglia and thought
to play a key role in nociceptive neurotransmission in the spinal dorsal
horn. Hypersensitivity to CGRP and/or sprouting in response to injury
may contribute to allodynia and hyperalgesia in persistent neuropathic
pain. A truncated CGRP peptide, CGRP
8-37
, can reverse symptoms of
neuropathic and inflammatory pain in animal models. This study aims
to test the analgesic potential of the neuropathic pain gene therapy
candidate CGRP
8-37
. The CGRP
8-37
fragment from human CGRP
cDNA was cloned to the peptidylglycine-amidating monooxygenase
(ssPAM/pGEMT) signal peptide to allow CGRP
8-37
to be amidated and
secreted, and subcloned into AAV- and Lenti-EGFP plasmids. Im-
munocytochemical colocalization of anti-CGRP and Golgi marker anti-
Giantin antibody confirmed secretable CGRP
8-37
peptide. For initial
screening, CGRP
8-37
supernatant transfected HEK cells was intrathe-
cally injected into rats with chronic constriction injury (CCI) and for-
malin-evoked inflammatory pain model. Results showed that reduction
of mechanical, tactile, cold allodynia and formalin-evoked pain re-
sponses treated with AAV-CGRP
8-37
supernatant was comparable with
the effect of 10 nM CGRP
8-37
peptide, but not in controls. Spinal cord
clip compression injury was induced pain-related behavior in rats. At 4
weeks post-injury when pain-related behavior was clearly established,
animals were injected with lenti-ssPAM-CGRP
8-37
-EGFP or control
virus intraspinally into lumbar dorsal horn. Attenuation of tactile, me-
chanical and cold allodynia was observed by 2 weeks post injection
with gradual improvement of behavioral outcomes towards pre-injury
levels by 12 weeks post-SCI. In contrast, allodynia persisted in rats
receiving control virus. Our findings suggest that engineered analgesic
CGRP
8-37
peptide have the potential to alleviate SCI-induced pain.
Supported by the Sheila and David Fuente Neuropathic Pain Pro-
gram, University of Miami Research Support Award, and Buoniconti
Fund to Cure Paralysis
Keywords: CGRP8-37, spinal cord injury, gene therapy, chronic
pain
S11-02
LONGITUDINAL OPTOGENETIC MAPPING OF THE COR-
TICOSPINAL TRACT AS A NOVEL APPROACH FOR
FUNCTIONAL EVALUATION OF SPINAL CORD INJURY
Xiaoming Jin
1,2
, Xingjie Ping
1
, Wei Wu
2
, Tyler Nguyen
1
, Wenhui
Xiong
1
, Xiao-Ming Xu
1,2
1
Indiana University School of Medicine, Anatomy and Cell Biology,
Indianapolis, USA
2
Indiana University School of Medicine, Neurological Surgery, In-
dianapolis, USA
Spinal cord injury (SCI) causes immediate disruption of ascending and
descending pathways, which are commonly followed by plasticity and
reorganization of these pathways at various levels of the central nervous
system. For the motor system, evaluating longitudinal changes in the
integrity and function of the corticospinal tract (CST) following SCI is
important for understanding injury mechanisms and assessing the effi-
cacy of therapeutic interventions. However, no techniques are currently
available for this purpose. Our goal was to use
in vivo
transcranial op-
togenetic mapping of the motor cortex for longitudinally assessing the
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