Long-term in vivo imaging technique developed to better understand and
treat spinal cord injury

Date:
April 12, 2022
Source:
Hong Kong University of Science and Technology
Summary:
A research team has developed an innovative technology for in
vivo imaging of the important biological processes involved in
the injury and repair of spinal cords, paving the way for a better
understanding of the pathology and potential treatment of spinal
cord injury (SCI).



FULL STORY ==========================================================================
A research team led by scientists from the Hong Kong University of Science
and Technology (HKUST) has developed an innovative technology for in vivo imaging of the important biological processes involved in the injury
and repair of spinal cords, paving the way for a better understanding
of the pathology and potential treatment of spinal cord injury (SCI).


==========================================================================
A tight bundle of neural cells (neurons and glia) and nerve pathways
(axons), the spinal cord serves as a primary information highway between
the brain and the peripheral nerves in the rest of our body. Damage to
the spinal cord is a devastating and largely irreversible neurological
trauma, and can result in lifelong disability and paralysis with no
available cure.

While Imaging plays an important role in understanding spinal cord
functions and its response to pathological insults and therapeutic
procedures, there is currently no effective method to capture the injured spinal cord at the level of cellular processes without activating the
immune response. Conventional imaging techniques require the patients
to have their spinal cord tissue removed to increase image resolution,
or run the risk of triggering immune responses in spinal cord tissue,
which may affect the disease process being investigated.

Now, a research team led by Prof. QU Jianan, professor of Department
of Electrical & Computer Engineering, and Prof. LIU Kai, associate
professor of Division of Life Science at HKUST, has demonstrated a new
approach to achieve long-term, repetitive, stable, high-resolution,
and inflammation-free in vivo spinal cord imaging in mouse models.

In their proposed protocol, ligamentum flavum (LF) -- the ligaments
connecting adjacent vertebrae in our spine -- is retained to protect
the underlying spinal cord tissue and reduce the risk of imaging window activating inflammation. But retaining the LF layer also means sacrificing
the imaging quality, because the layer introduces optical scattering
and results in decreased penetration depth of spinal cord imaging.

To solve this problem, the team applied iodixanol, an FDA-approved
non-toxic compound, as an optical clearing medium for the imaging window
and greatly enhanced its transparency as well as image contrast and
resolution. Compared with the prior methods, the iodixanol-based optical clearing technique allows the researchers to remove less tissue above
the spinal cord without compromising imaging quality, thus significantly extending the number of imaging sessions to up to 15 sessions over
167 days.

Using this optically cleared intervertebral window, the team studied
neuron- glia dynamics and observed strengthened contact of microglia with
the nodes of Ranvier during axonal degeneration, opening a promising
way to study the interaction between immune cells and nodes of Ranvier
under normal and injury conditions. The results were recently published
in Nature Communications.

"Considering the difficulties associated with long-term and repetitive
spinal cord imaging, this innovation will be an important and widely
used tool for the study of spinal cord injury," said Prof. Qu, who is an
expert of optical engineering and science with extensive experience in in vivolinear and nonlinear optical spectroscopy and imaging of biological
tissues from a variety of animal models.

"By avoiding surgery-induced inflammation, we can track microglia from
resting to activation stages and understand its functional interaction
with degenerating and regenerating axons in the spinal cord," added
Prof. Liu, whose research interests include the cellular and molecular mechanisms of axonal regeneration in the adult mammalian central
nervous system. "In vivo imaging in living animal models will reveal
new biological insights leading to efficient therapeutic strategies for
SCI treatment."

========================================================================== Story Source: Materials provided by Hong_Kong_University_of_Science_and_Technology. Note: Content may be
edited for style and length.


========================================================================== Journal Reference:
1. Wanjie Wu, Sicong He, Junqiang Wu, Congping Chen, Xuesong Li,
Kai Liu,
Jianan Y. Qu. Long-term in vivo imaging of mouse spinal cord through
an optically cleared intervertebral window. Nature Communications,
2022; 13 (1) DOI: 10.1038/s41467-022-29496-x ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/04/220412095342.htm

--- up 6 weeks, 1 day, 10 hours, 51 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)