Biomechanical Analysis of Experimental Diffuse Axonal Injury

Abstract

The purpose of this paper is to present results from methodologies used in our laboratory that are targeted toward identifying specific brain injury thresholds. Results from studying one form of brain injury, diffuse axonal injury, are presented in this report. Physical models, or surrogates, of the skull-brain complex are used to estimate the relationship between inertial loading and brain deformation. A porcine model of diffuse axonal injury, developed with information from these physical models and earlier in vitro tissue modeling studies, is used to correlate histologic and radiologic evidence of axonal injury to predicted regions of injury from the experimental and theoretical analysis. These results form the basis for developing improved diffuse brain injury tolerance levels, as well as identifying new means of diagnostic and treatment techniques for diffuse axonal injury.

Modelos experimentales de traumatismo craneoencefálico

“…Estudios pioneros realizados por Ommaya et al demostraron que la aceleración umbral necesaria para causar un daño aumenta rápidamente al disminuir la masa cerebral 85 . Por lo tanto, los modelos de daño por aceleración son más fáciles de desarrollar en animales con una cabeza de mayor tamaño, como son los monos y cerdos 42,80 . Sin embargo, debido al alto coste y más difícil manejo de estos animales, se han desarrollado en la última década modelos de daño difuso en roedores 20,21,47,73 .…”

“…Trata de reproducir la deformación tisular que se produce durante la acción de fuerzas de inercia sobre el cráneo in vivo 80 . El modelo inicial consistía en el estiramiento bidireccional de dos membranas elásticas entre las que se disponían células en cultivo.…”

Modélisationin vitrodu système nerveux par génie tissulaire

“…La première technique consistait à déchirer ou à lacérer des cellules en culture avec une pointe, un poinçon ou un laser [9]. Mais, une autre technique très utilisée in vitro est celle de l'étirement des cellules, qui reproduit l'étendue et le taux de déformation du tissu survenant in vivo pendant une blessure [10]. Il est ainsi possible de repérer les cellules du système nerveux vulnérables à certains types de déformations mécaniques et d'évaluer si les méca-nismes de blessures changent lorsque la déformation des cellules se fait par étirement, par compression ou par la force de cisaillements [11,12].…”

Traumatic injury induces differential expression of cell death genes in organotypic brain slice cultures determined by complementary DNA array hybridization

“…1,22 Using techniques to compare the estimated pattern of tissue deformation to the in vivo injury distribution, it has been proposed that deformations between 0.10 and 0.50 with strain rates in the order of 10-50/s were necessary to cause primary mechanical tissue damage. 41,44 The device utilized in the current study was capable of accurately and reproducibly generating deformations within the range associated with in vivo damage and allowed for the independent specification of critical mechanical parameters of injury including maximum strain, strain rate, relaxation rate and duration. 48 This injury was produced by deformation of the silicone membrane on which the cultures were grown.…”