Characterization of rat forepaw function in two models of cervical dorsal root injury

Ann Wu*, Jenny L. Lauschke, Renee Morris, Phil M. E. Waite

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

Dorsal root injury (DRI) disrupts afferent input from the periphery and often leads to sensory deficits and neuropathic pain. Despite cervical root injuries in rodents being a useful model for deafferentation studies, a quantitative characterization of the sensory deficits produced by DRI is still lacking. This study aimed to characterize the different functional deficits resulting from a dorsal two- or four-root (C7-C8 and C5-C8, respectively) crush injury in rats at levels that innervate the forepaws. The impairment of the affected forepaw was assessed by mechanical and thermal pain responses, and rating the performance on the skilled reaching and ladder rung walking tests (LRWT). Postoperatively, only the two- root DRI rats developed mechanical allodynia, which persisted throughout the course of the study. Thermal hyperalgesia peaked at weeks 1 and 6. The four-root DRI animals were less sensitive to mechanical and thermal stimulation. Performance on the skilled reaching task could only be measured in two- root DRI rats, as animals with four-root injury were unable to grasp the pellets at all. On the LRWT, gait impairment was proportional to the severity of the lesion, with four-root DRI animals showing a significantly higher rate of errors than two- root DRI animals. These results suggest that two-root DRI represents a good model to assess treatments for allodynia-induced neuropathic pain, and for the restoration of the sensory component of the skilled motor performance. On the other hand, the four-root DRI would be a useful model when forepaw deafferentation is required.

Original languageEnglish
Pages (from-to)17-29
Number of pages13
JournalJournal of Neurotrauma
Volume26
Issue number1
DOIs
Publication statusPublished - Jan 2009
Externally publishedYes

Keywords

  • dorsal root injury
  • neuropathic pain
  • skilled reaching
  • horizontal error ladder
  • SPINAL-CORD-INJURY
  • ENSHEATHING GLIA TRANSPLANTS
  • PERIPHERAL-NERVE INJURY
  • BRACHIAL-PLEXUS INJURY
  • NEUROPATHIC PAIN
  • SELF-MUTILATION
  • ADULT-RATS
  • ENTRY ZONE
  • AXON REGENERATION
  • CENTRAL TERMINALS

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