The Journal of Bone and Joint Surgery (American). 2006;88:2400-2410.
doi:10.2106/JBJS.E.01424
© 2006 The Journal of Bone and Joint Surgery, Inc.
Transplantation of Preconditioned Schwann Cells in Peripheral Nerve Grafts After Contusion in the Adult Spinal Cord
Improvement of Recovery in a Rat Model
Alexandre Rasouli, MD1,
Nitin Bhatia, MD1,
Sourabh Suryadevara, BS1,
Kim Cahill, BS1 and
Ranjan Gupta, MD1
1 University of California, Irvine, 2226 Gillespie Neuroscience Research
Facility, Irvine, CA 92697. E-mail address for R. Gupta:
ranjang{at}uci.edu
Investigation performed at the University of California, Irvine,
California
In support of their research for or preparation of this manuscript, R.
Gupta received grants or outside funding from the National Institute of
Neurological Disorders and Stroke (NS02221 and NS049203) and the Roman Reed
Foundation. None of the authors received payments or other benefits or a
commitment or agreement to provide such benefits from a commercial entity. No
commercial entity paid or directed, or agreed to pay or direct, any benefits
to any research fund, foundation, educational institution, or other charitable
or nonprofit organization with which the authors are affiliated or
associated.
Background: Recovery after injury to the peripheral nervous system
is based on the pro-regenerative relationship between axons and the
extracellular matrix, a relationship established by Schwann cells. As
mechanical conditioning of Schwann cells has been shown to stimulate their
regenerative behavior, we sought to determine whether transplantation of these
cells to the central nervous system (i.e., the spinal cord), with its limited
regenerative capacity after injury, would improve axonal regeneration and
functional recovery.
Methods: A moderate contusion injury of the spinal cord was created
with a force-directed impactor in forty-eight adult Sprague-Dawley rats, and,
at one week postinjury, the spinal cords were reexposed in all animals. In
twenty-four of these animals, peripheral nerve grafts with Schwann cells that
had been obtained from the sciatic nerves of donor animals, and had been
either untreated or subjected to mechanical conditioning, were transplanted to
the contused area of the cords following resection of the glial scar. Another
group of animals was treated with glial scar excision only, and a fourth group
had the contusion injury but neither glial excision nor transplantation.
Scores according to the Basso, Beattie, Bresnahan (BBB) Locomotor Rating Scale
were assigned preoperatively and weekly thereafter. Tract tracing of
descending and ascending spinal cord tracts was performed at six weeks
postoperatively for quantitative histological evaluation of axonal
regeneration.
Results: While the recovery following glial scar excision without
peripheral nerve transplantation was significantly worse than the recovery in
the other groups, both transplantation groups had significantly higher BBB
scores than the controls (no transplantation) in the early postoperative
period (p < 0.05). Moreover, histological analysis showed markedly
increased axonal regeneration at the lesional sites in the animals treated
with the mechanically conditioned grafts than in the other groups (p <
0.05).
Conclusions: Functional recovery after spinal cord contusion
improved following glial scar excision with transplantation of Schwann cells
in peripheral nerve grafts to the contusion areas. Although recovery did not
differ significantly between the transplantation groups, only the
preconditioned grafts led to axonal regeneration at and past the lesional
site. These grafts may further enhance functional recovery as the descending
tracts eventually reach their target end-organs.
Clinical Relevance: Transplantation of Schwann cells in peripheral
nerve grafts significantly improved functional and axonal recovery following a
contusion spinal cord injury in rats and warrants further investigation for
potential clinical applications.

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