Spinal Cord Injury Results in Chronic Mechanical Stiffening

John G. Cooper, Delphine Sicard, Sripadh Sharma, Stephanie Van Gulden, Tammy L. McGuire, Miguel Pareja Cajiao, Daniel J. Tschumperlin, John A. Kessler

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

Gliosis and fibrosis after spinal cord injury (SCI) lead to formation of a scar that is thought to present both molecular and mechanical barriers to neuronal regeneration. The scar consists of a meshwork of reactive glia and deposited, cross-linked, extracellular matrix (ECM) that has long been assumed to present a mechanically "stiff" blockade. However, remarkably little quantitative information is available about the rheological properties of chronically injured spinal tissue. In this study we utilize atomic force microscopy microindentation to provide quantitative evidence of chronic mechanical stiffening after SCI. Using the results of this tissue characterization, we assessed the sensitivity of both mouse and human astrocytes in vitro and determined that they are exquisitely mechanosensitive within the relevant range of substrate stiffness observed in the injured/uninjured spinal cord. We then utilized a novel immune modifying nanoparticle (IMP) treatment as a tool to reveal fibrotic scarring as one of the key drivers of mechanical stiffening after SCI in vivo. We also demonstrate that glial scar-forming astrocytes form a highly aligned, anisotropic network of glial fibers after SCI, and that IMP treatment mitigates this pathological alignment. Taken together, our results identify chronic mechanical stiffening as a critically important aspect of the complex lesion milieu after SCI that must be considered when assessing and developing potential clinical interventions for SCI.

Original languageEnglish (US)
Pages (from-to)494-506
Number of pages13
JournalJournal of neurotrauma
Volume37
Issue number3
DOIs
StatePublished - Feb 1 2020

Keywords

  • fibrotic scar
  • immune modifying nanoparticles
  • mechanical properties
  • spinal cord injury
  • stiffness

ASJC Scopus subject areas

  • Clinical Neurology

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  • Cite this

    Cooper, J. G., Sicard, D., Sharma, S., Van Gulden, S., McGuire, T. L., Cajiao, M. P., Tschumperlin, D. J., & Kessler, J. A. (2020). Spinal Cord Injury Results in Chronic Mechanical Stiffening. Journal of neurotrauma, 37(3), 494-506. https://doi.org/10.1089/neu.2019.6540