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In This Article

  • Summary
  • Abstract
  • Introduction
  • Protocol
  • Representative Results
  • Discussion
  • Acknowledgements
  • Materials
  • References
  • Reprints and Permissions

Summary

The rat thoracic spinal hemisection is a valuable and reproducible model of unilateral spinal cord injury to investigate the neural mechanisms of locomotor recovery and treatment efficacy. This article includes a detailed step-by-step guide to perform the hemisection procedure and to assess locomotor performance in an open-field arena.

Abstract

Spinal cord injury (SCI) causes disturbances in motor, sensory, and autonomic function below the level of the lesion. Experimental animal models are valuable tools to understand the neural mechanisms involved in locomotor recovery after SCI and to design therapies for clinical populations. There are several experimental SCI models including contusion, compression, and transection injuries that are used in a wide variety of species. A hemisection involves the unilateral transection of the spinal cord and disrupts all ascending and descending tracts on one side only. Spinal hemisection produces a highly selective and reproducible injury in comparison to contusion or compression techniques that is useful for investigating neural plasticity in spared and damaged pathways associated with functional recovery. We present a detailed step-by-step protocol for performing a thoracic hemisection at the T8 vertebral level in the rat that results in an initial paralysis of the hindlimb on the side of the lesion with graded spontaneous recovery of locomotor function over several weeks. We also provide a locomotor scoring protocol to assess functional recovery in the open-field. The locomotor assessment provides a linear recovery profile and can be performed both early and repeatedly after injury in order to accurately screen animals for appropriate time points in which to conduct more specialized behavioral testing. The hemisection technique presented can be readily adapted to other transection models and species, and the locomotor assessment can be used in a variety of SCI and other injury models to score locomotor function.

Introduction

Spinal cord injury (SCI) is associated with severe disturbances in motor, sensory, and autonomic function. Experimental animal models of SCI are valuable tools to understand the anatomical and physiological events involved in SCI pathology, to investigate the neural mechanisms in repair and recovery, and to screen for efficacy and safety of potential therapeutic interventions. The rat is the most commonly used species in SCI research1. Rat models are low cost, easy to reproduce, and a large battery of behavioral tests are available to assess functional outcomes2. Despite some differences in tract locations, the rat spina....

Protocol

The experiments described in this article were performed in compliance with the guidelines of the Canadian Council on Animal Care and were approved by the ethics committee at the Université de Montréal.

1. Thoracic hemisection surgery

  1. Wear appropriate protective equipment (gloves, mask, and gown) to maintain an aseptic environment for surgery. Clean the surgical area with alcohol wipes, and place sterile surgical drapes over the surgical field. Sterilize surgical tools an.......

Representative Results

Reproducible lesions with a high degree of consistency can be generated with the hemisection technique. To assess and compare lesions sizes between experimental groups, the maximal area of the lesion as a percentage of the total cross-section of the spinal cord can be readily calculated with histological staining of spinal cord sections. Figure 1 shows a representative lesion of the left hemicord and an overlay of the proportion of maximal lesion area shared between rats with a mean lesion s.......

Discussion

A major strength of the hemisection technique is the selectivity and reproducibility of the lesion which leads to reduced variability in histological and behavioral phenotypes between animals25. In order to ensure a unilateral lesion at the appropriate spinal level, accurate identification of both the proper vertebral segment and spinal cord midline is critical. As there can be a tendency for the spinal cord to rotate in the direction of the cut during the hemisection procedure, it can be benefici.......

Acknowledgements

This work was supported by the Canadian Institutes for Health Research (CIHR; MOP-142288) to M.M. M.M. was supported by a salary award from Fonds de Recherche Québec Santé (FRQS), and A.R.B was supported by a fellowship from FRQS.

....

Materials

NameCompanyCatalog NumberComments
BaytrilCDMV11242
Blunt dissection scissorsWorld Precision Instruments503669
Buprenorphine hydrochorideCDMV
Camera lensPentaxC31204TH12.5-75mm, f1.8, 2/3" format, C-mount
CMOS video cameraBasleracA2000-165uc2/3" format, 2048 x 1088 pixels, up to 165 fps, C-mount, USB3
Compressed oxygen gasPraxair
Cotton tipped applicatorsCDMV108703
Delicate bone trimmersFine Science Tools16109-14
Dissecting knifeFine Science Tools10055-12
Dumont fine forceps (#5)Fine Science Tools11254-20
Ethicon Vicryl 4/0 Violet Braided FS-2  suture (J392H)CDMV111689
Feedback-controlled heating padHarvard Apparatus55-7020
Female Long-Evans ratsCharles River LaboratoriesStrain code: 006225-250g
GelfoamCDMV102348
Curved hemostat forcepsFine Science Tools13003-10
Hot bead sterilizerFine Science Tools18000-45
Hydrogel70-01-5022Clear H20
IsofluoraneCDMV118740
Lactated Ringer's solutionCDMV116373
Lidocaine (2%)CDMV123684
Needle 30 gaCDMV4799
Open-field areaCustomCircular Plexiglas arena 96 cm diameter, 40 cm wall height
Opthalmic ointmentCDMV110704
Personal computer With USB3 connectivity to record video with the listed camera
Physiological salineCDMV1399
ProviodineCDMV4568
Rodent Liquid DietBioservF1268
Scalpal blade #11CDMV6671
Self-retaining retractorWorld Precision Instruments14240
Vannas iridectomy spring scissorsFine Science Tools15002-08
Veterinary Anesthesia Machine and isofluarane vaporizerDispomed975-0510-000
VLC media playerVideoLANvideolan.org/vlc

References

  1. Sharif-Alhoseini, M., et al. Animal models of spinal cord injury: a systematic review. Spinal Cord. 55 (8), 714-721 (2017).
  2. Sedy, J., Urdzikova, L., Jendelova, P., Sykova, E. Methods for behavioral testing of spinal cord injured rats.

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