Transplants of Fibroblasts Genetically Modified to Express BDNF Promote Axonal Regeneration from Supraspinal Neurons Following Chronic Spinal Cord Injury

doi:10.1006/exnr.2002.7980

Experimental Neurology

Volume 177, Issue 1, September 2002, Pages 265-275

https://doi.org/10.1006/exnr.2002.7980 Get rights and content

Abstract

Transplants of fibroblasts genetically modified to express BDNF (Fb/BDNF) have been shown to promote regeneration of rubrospinal axons and recovery of forelimb function when placed acutely into the injured cervical spinal cord of adult rats. Here we investigated whether Fb/BDNF cells could stimulate supraspinal axon regeneration and recovery after chronic (4 week) injury. Adult female Sprague-Dawley rats received a complete unilateral hemisection injury at the third cervical spinal cord segment (C3). Four–five weeks later the injury site was exposed and rats received transplants of unmodified fibroblasts (Fb/UM) or Fb/BDNF. Four–five weeks after transplantation, locomotor recovery was examined on a test of forelimb usage and regeneration of supraspinal axons was studied following injection of the anterograde tracer biotin dextran amine (BDA). Rubrospinal tract (RST), reticulospinal tract (ReST), and vestibulospinal tract (VST) axons regenerated into transplants of either Fb/UM or Fb/BDNF but the length of axonal growth was significantly different in the two groups. The absolute distance of ReST growth was 1.8-fold greater in Fb/BDNF than in Fb/UM and the absolute distance of growth of RST and VST axons showed a statistically significant 4-fold increase. All three types of regenerated axons occupied a greater proportional length of Fb/BDNF transplants than of Fb/UM transplants. Only VST axons extended into the host spinal cord caudal to the Fb/BDNF grafts, but these axons were sparse. Rats receiving Fb/BDNF used both forelimbs together to explore walls of a cylinder more often than rats receiving Fb/UM, indicating partial recovery of forelimb usage. These results demonstrate that fibroblasts genetically modified to express BDNF promote axon regeneration from supraspinal neurons in the chronically injured spinal cord with accompanying partial recovery of locomotor performance.

References (46)

M.S. Beattie et al.
Endogenous repair after spinal cord contusion injuries in the rat
Exp. Neurol.
(1997)
A Blesch et al.
Neurotrophin gene therapy in CNS models of trauma and degeneration
Prog. Brain Res.
(1998)
B.S. Bregman et al.
Neurotrophic factors increase axonal growth after spinal cord injury and transplantation in the adult rat
Exp. Neurol.
(1997)
B.S. Bregman et al.
Transplants and neurotrophic factors prevent atrophy of mature CNS neurons after spinal cord injury
Exp. Neurol.
(1998)
P. Caroni et al.
Antibody against myelin-associated inhibitor of neurite growth neutralizes nonpermissive substrate properties of CNS white matter
Neuron
(1988)
J.D Houle
Demonstration of the potential for chronically injured neurons to regenerate axons into intraspinal peripheral nerve grafts
Exp. Neurol.
(1991)
J.D. Houle et al.
Regrowth of calcitonin gene-related peptide (CGRP) immunoreactive axons from chronically injured rat spinal cord into fetal spinal cord tissue transplants
Neurosci. Lett.
(1989)
J.H. Houle et al.
Survival of chronically-injured neurons can be prolonged by treatment with neurotrophic factors
Neuroscience
(1999)
D.A. Houweling et al.
Local application of collagen containing brain-derived neurotrophic factor decreases the loss of function after spinal cord injury in the adult rat
Neurosci. Lett.
(1998)
L.B. Jakeman et al.
Brain-derived neurotrophic factor stimulates hindlimb stepping and sprouting of cholinergic fibers after spinal cord injury
Exp. Neurol.
(1998)

J.P. Merlio et al.

Molecular cloning of rat trkC and distribution of cells expressing messenger RNAs for members of the trk family in the rat central nervous system

Neuroscience

(1992)

G.W. Plant et al.

Inhibitory proteoglycan immunoreactivity is higher at the caudal than the rostral Schwann cell graft-transected spinal cord interface

Mol. Cell. Neurosci.

(2001)

P.M. Richardson et al.

Peripheral nerve autografts to the rat spinal cord: Studies with axonal tracing methods

Brain Res.

(1982)

T. Schallert et al.

CNS plasticity and assessment of forelimb sensorimotor outcome in unilateral rat models of stroke, cortical ablation, parkinsonism and spinal cord injury

Neuropharmacology

(2000)

W. Tetzlaff et al.

Response of rubrospinal and corticospinal neurons to injury and neurotrophins. Prog

Brain Res.

(1994)

M.H. Tuszynski et al.

Fibroblasts genetically modified to produce nerve growth factor induce robust neurite ingrowth after grafting to the spinal cord

Exp. Neurol.

(1994)

M.H. Tuszynski et al.

Nerve growth factor delivery by gene transfer induces differential outgrowth of sensory, motor and noradrenergic neurites after adult spinal cord injury

Exp. Neurol.

(1996)

M.H. Tuszynski et al.

Functional characterization of NGF-secreting cell grafts to the acutely injured spinal cord

Cell Transplant.

(1997)

M.C. Wallace et al.

Chronic regenerative changes in the spinal cord after cord compression injury in rats

Surg. Neurol.

(1987)

X.M. Xu et al.

A combination of BDNF and NT-3 promotes supraspinal axonal regeneration into Schwann cell grafts in adult rat thoracic spinal cord

Exp. Neurol.

(1995)

J.H. Ye et al.

Treatment of the chronically injured spinal cord with neurotrophic factors can promote axonal regeneration into intraspinal peripheral nerve grafts

Exp. Neurol.

(1997)

E.J. Bradbury et al.

Chondroitinase ABC promotes functional recovery after spinal cord injury

Nature

(2002)

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Citation Excerpt :
Subsequently, using cells genetically modified to overexpress growth factors may be a helpful strategy in achieving a sustainable amount of neural growth. In recent years, numerous preclinical studies have been performed on the effects of the administration of cells genetically modified to overexpress growth factors in SCI.15-18 However, findings of these studies are contradictory in some cases.
Numerous preclinical studies have been performed in recent years on the effects of the administration of growth factor gene-modified cells in spinal cord injury (SCI). However, findings of these studies are contradictory.
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¹: Current address: Department of Anatomy and Neurobiology, University of Kentucky Medical Center, Lexington, KY 40536.

²: To whom correspondence should be addressed at Department of Anatomy and Neurobiology, University of Arkansas for Medical Science, 4301 West Markham Street, Little Rock, AR 72205. Fax: (501) 526-6756. E-mail: [email protected].

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Regular ArticleTransplants of Fibroblasts Genetically Modified to Express BDNF Promote Axonal Regeneration from Supraspinal Neurons Following Chronic Spinal Cord Injury

Abstract

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Regular Article
Transplants of Fibroblasts Genetically Modified to Express BDNF Promote Axonal Regeneration from Supraspinal Neurons Following Chronic Spinal Cord Injury