title: Relating Histopathology and Mechanical Strain in Experimental Contusion Spinal Cord Injury in a Rat Model.
abstract: During traumatic spinal cord injury (SCI), the spinal cord is subject to external displacements that result in damage of neural tissues. These displacements produce complex internal deformations, or strains, of the spinal cord parenchyma. The aim of this study is to determine a relationship between these internal strains during SCI and primary damage to spinal cord gray matter (GM) in an in vivo rat contusion model. Using magnetic resonance imaging and novel image registration methods, we measured three-dimensional (3D) mechanical strain in in vivo rat cervical spinal cord (n = 12) during an imposed contusion injury. We then assessed expression of the neuronal transcription factor, neuronal nuclei (NeuN), in ventral horns of GM (at the epicenter of injury as well as at intervals cranially and caudally), immediately post-injury. We found that minimum principal strain was most strongly correlated with loss of NeuN stain across all animals (R(2) = 0.19), but varied in strength between individual animals (R(2) = 0.06-0.52). Craniocaudal distribution of anatomical damage was similar to measured strain distribution. A Monte Carlo simulation was used to assess strain field error, and minimum principal strain (which ranged from 8% to 36% in GM ventral horns) exhibited a standard deviation of 2.6% attributed to the simulated error. This study is the first to measure 3D deformation of the spinal cord and relate it to patterns of ensuing tissue damage in an in vivo model. It provides a platform on which to build future studies addressing the tolerance of spinal cord tissue to mechanical deformation.
authors.affiliation: 1 International Collaboration On Repair Discoveries (ICORD), University of British Columbia, Vancouver , British Columbia, Canada .|2 Department of Mechanical Engineering, University of British Columbia , Vancouver, British Columbia, Canada .
authors.forename: Tim
authors.initials: T
authors.lastname: Bhatnagar
authors.affiliation: 1 International Collaboration On Repair Discoveries (ICORD), University of British Columbia, Vancouver , British Columbia, Canada .
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.affiliation: 1 International Collaboration On Repair Discoveries (ICORD), University of British Columbia, Vancouver , British Columbia, Canada .|3 UBC MRI Research Center, University of British Columbia , Vancouver, British Columbia, Canada .
authors.forename: Andrew
authors.initials: A
authors.lastname: Yung
authors.affiliation: 1 International Collaboration On Repair Discoveries (ICORD), University of British Columbia, Vancouver , British Columbia, Canada .|2 Department of Mechanical Engineering, University of British Columbia , Vancouver, British Columbia, Canada .
authors.forename: Peter
authors.initials: P
authors.lastname: Cripton
authors.affiliation: 1 International Collaboration On Repair Discoveries (ICORD), University of British Columbia, Vancouver , British Columbia, Canada .|3 UBC MRI Research Center, University of British Columbia , Vancouver, British Columbia, Canada .
authors.forename: Piotr
authors.initials: P
authors.lastname: Kozlowski
authors.affiliation: 1 International Collaboration On Repair Discoveries (ICORD), University of British Columbia, Vancouver , British Columbia, Canada .|4 Department of Zoology, University of British Columbia , Vancouver, British Columbia, Canada .
authors.forename: Wolfram
authors.initials: W
authors.lastname: Tetzlaff
authors.affiliation: 1 International Collaboration On Repair Discoveries (ICORD), University of British Columbia, Vancouver , British Columbia, Canada .|2 Department of Mechanical Engineering, University of British Columbia , Vancouver, British Columbia, Canada .|5 Department of Orthopedics, University of British Columbia , Vancouver, British Columbia, Canada .
authors.forename: Thomas
authors.initials: T
authors.lastname: Oxland
mesh_terms: D000818:Animals; D003288:Contusions / Q000473:pathology*; D066128:Gray Matter / Q000000981:diagnostic imaging / Q000473:pathology*; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013119:Spinal Cord Injuries / Q000000981:diagnostic imaging / Q000473:pathology*; D013314:Stress, Mechanical
keywords: MRI; biomechanics; contusion; histology; image registration; in vivo; spinal cord injury