Citation

Effgen GB, Ong T, Nammalwar S, Ortuno AI, Meaney D, Bass C', Morrison Iii B. J. Neurotrauma 2015; 33(20): 1901-1912.

Affiliation

Columbia University, Biomedical Engineering , 1210 Amsterdam Ave. , MC8904 , New York, New York, United States , 10027 , 212-854-6277 , 212-854-8725 ; bm2119@columbia.edu.

Copyright

(Copyright © 2015, Mary Ann Liebert Publishers)

DOI

10.1089/neu.2015.4327

PMID

26699926

Abstract

Up to 80% of injuries sustained by US soldiers in Operation Enduring Freedom and Operation Iraqi Freedom were the result of blast exposure from improvised explosive devices (IEDs). Some soldiers experience multiple blasts while on duty, and it has been suggested that symptoms of repetitive blast are similar to those that follow multiple non-blast concussions, such as sport-related concussion. Despite the interest in the effects of repetitive blast exposure, it remains unknown whether an initial blast renders the brain more vulnerable to subsequent exposure resulting in a synergistic injury response. To investigate the effect of multiple primary blasts on the brain, organotypic hippocampal slice cultures were exposed to single or repetitive (2 or 3 total) primary blasts of varying intensities. Long-term potentiation was significantly reduced following two Level 2 (92.7 kPa, 1.4 ms, 38.5 kPa·ms) blasts delivered 24 hours apart without altering basal evoked response. This deficit persisted when the interval between injuries was increased to 72 hours but not when the interval was extended to 144 hours. The repeated blast exposure with a 24 hour interval increased microglia staining and activation significantly but did not significantly increase cell death or damage axons, dendrites, or principal cell layers. Lack of overt structural damage and change in basal stimulated neuron response suggests that injury from repetitive primary blast exposure may specifically affect long-term potentiation. Our studies suggest repetitive primary blasts can exacerbate injury dependent on the injury severity and interval between exposures.

Language: en