Citation

Sawyer T, Wang Y, Ritzel DV, Josey T, Villanueva M, Shei Y, Nelson P, Hennes G, Weiss T, Vair C, Fan C, Barnes J. J. Neurotrauma 2015; 33(13): 1181-1193.

Affiliation

DRDC Suffield Research Centre, Medicine Hat, Alberta, Canada ; Juliabarnes@dal.ca.

Copyright

(Copyright © 2015, Mary Ann Liebert Publishers)

DOI

10.1089/neu.2015.3914

PMID

26582146

Abstract

The role of primary blast in blast-induced traumatic brain injury is controversial in part due to the technical difficulties of generating free-field blast conditions in the laboratory. The use of traditional shock tubes often results in artifacts, particularly of dynamic pressure, while the forces affecting the head are dependent on where the animal is placed relative to the tube, whether the exposure is whole-body or head-only, and on how the head is actually exposed to the insult (restrained or not). An Advanced Blast Simulator (ABS) has been developed that enables high fidelity simulation of free-field blast waves, including sharply defined static and dynamic overpressure rise times, underpressures and secondary shock waves. Rats were exposed in head-only fashion to single pulse blast-waves of 15-30 psi static overpressure. Head restraints were configured so as to eliminate concussive and minimize whiplash forces exerted on the head, as shown by kinematic analysis. No overt signs of trauma were present in the animals post-exposure. However, significant changes in brain CNPase and neurofilament heavy chain levels were evident by seven days. In contrast to most studies of primary blast-induced TBI, no elevation of GFAP levels was noted when head movement was minimized. The ABS described in this report enables the generation of shock waves highly representative of free-field blast. The use of this technology, in concert with head-only exposure, minimized head movement and the kinematic analysis of the forces exerted on the head, provide convincing evidence that primary blast directly causes changes in brain function and that GFAP may not be an appropriate biomarker of primary blast-induced TBI.

Language: en