Chondroitinase ABC-mediated plasticity of spinal sensory function

J Neurosci. 2008 Nov 12;28(46):11998-2009. doi: 10.1523/JNEUROSCI.3877-08.2008.

Abstract

Experimental therapeutics designed to enhance recovery from spinal cord injury (SCI) primarily focus on augmenting the growth of damaged axons by elevating their intrinsic growth potential and/or by nullifying the influence of inhibitory proteins present in the mature CNS. However, these strategies may also influence the wiring of intact pathways. The direct contribution of such effects to functional restoration after injury has been mooted, but as yet not been described. Here, we provide evidence to support the hypothesis that reorganization of intact spinal circuitry enhances function after SCI. Adult rats that underwent unilateral cervical spared-root lesion (rhizotomy of C5, C6, C8, and T1, sparing C7) exhibited profound sensory deficits for 4 weeks after injury. Delivery of a focal intraspinal injection of the chondroitin sulfate proteoglycan-degrading enzyme chondroitinase ABC (ChABC) was sufficient to restore sensory function after lesion. In vivo electrophysiological recordings confirm that behavioral recovery observed in ChABC-treated rats was consequent on reorganization of intact C7 primary afferent terminals and not regeneration of rhizotomized afferents back into the spinal cord within adjacent segments. These data confirm that intact spinal circuits have a profound influence on functional restoration after SCI. Furthermore, comprehensive understanding of these targets may lead to therapeutic interventions that can be spatially tailored to specific circuitry, thereby reducing unwanted maladaptive axon growth of distal pathways.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Action Potentials / physiology
  • Afferent Pathways / drug effects
  • Afferent Pathways / enzymology
  • Afferent Pathways / injuries
  • Animals
  • Chondroitin ABC Lyase / metabolism
  • Chondroitin ABC Lyase / pharmacology*
  • Chondroitin Sulfate Proteoglycans / drug effects
  • Chondroitin Sulfate Proteoglycans / metabolism
  • Disease Models, Animal
  • Male
  • Nerve Regeneration / drug effects
  • Nerve Regeneration / physiology
  • Neural Conduction / physiology
  • Neuronal Plasticity / drug effects*
  • Neuronal Plasticity / physiology
  • Rats
  • Rats, Wistar
  • Recovery of Function / drug effects
  • Recovery of Function / physiology
  • Rhizotomy*
  • Sensation Disorders / drug therapy
  • Sensation Disorders / etiology
  • Sensation Disorders / physiopathology
  • Sensory Receptor Cells / physiology
  • Spinal Cord / drug effects*
  • Spinal Cord / enzymology
  • Spinal Cord / physiopathology
  • Spinal Cord Injuries / drug therapy*
  • Spinal Cord Injuries / metabolism
  • Spinal Cord Injuries / physiopathology
  • Spinal Nerve Roots / drug effects*
  • Spinal Nerve Roots / enzymology
  • Spinal Nerve Roots / injuries
  • Treatment Outcome

Substances

  • Chondroitin Sulfate Proteoglycans
  • Chondroitin ABC Lyase