Measurement of Nerve Fiber Strain in Brain Tissue Subjected to Uniaxial Stretch (Comparison Between Local Strain of Nerve Fiber and Global Strain of Brain Tissue)

摘要

References(28) Cited-By(5) Diffuse axonal injury (DAI) is a specific type of closed head injury often seen in automobile accidents, that directly leads to the morbidity and mortality, however, the injury mechanism of DAI has yet to be clarified. DAI is characterized by structural and functional damage in nerve fibers in the white matter, which may be caused by excessive tensile strain. While the white matter has a network-like structure of nerve fibers embedded in neuroglia and the extracellular matrix, the nerve fibers are undulated and the mechanical properties of these components are not necessarily equal. Thus, the strain in the white matter can be different from that in the fibers. In this study, we have measured stretch ratios of the nerve fibers running in various directions in porcine brain tissue subjected to uniaxial stretch and compared them with global strain. It was found that the fiber direction positively correlated with neural fiber strain whilst the fiber strain was not equal to global strain. Particularly, the maximum neural fiber strain was ∼25% of its surrounding tissue strain, indicating that the local strain in the neural fibers is not equal to global strain in the brain tissue. Consideration of neural fiber alignment in the white matter is important in studying the mechanical aspects of pathogenesis of DAI.