Virginia Research Day 2022

Graduate Student Research Biomedical

01 Neurometabolic Profile Of Amino Acids Following Blast Exposure: A Preliminary Study

Carly Norris 1, 2 ; Susan Murphy 2 ; Justin Weatherbee 1 ; Pamela VandeVord 1, 2, 3 Corresponding author: carly8@vt.edu 1 Virginia Tech, Biomedical Engineering and Mechanics 2 Virginia Tech, School of Biomedical Engineering and Sciences 3 Salem Veterans Affairs Medical Center

at 48 hours also indicated signs of metabolic stress (p<0.1). This data supports the conclusion that exposure to a mild blast event leads to increased metabolic demand at 4 hr in the cortex and metabolic stress at 12 hr in the hippocampus and 48 hr in the cerebellum, contributing to secondary cascades. These findings also suggest that the brain regions are affected disproportionately at acute time points and have unique profiles up to 48 hr. Future work will expand the metabolic time points of interest with the aim of identifying potential therapeutic targets to mitigate secondary effects.

each brain region were extracted for each time point. High performance liquid chromatography with electrochemical detection was used to measure amino acid concentrations where external standards showed high sensitivity with an average correlation coefficient of 0.998 +/- 0.003. At 4 hr, all amino acid concentrations were moderately increased in the blast compared to the sham where most significant differences were seen in the cortex. However, the ratio of Glutamate (Glu) to gamma-Aminobutyric acid (GABA) remained unchanged. The Glu:GABA ratio in the hippocampus at 12 hr significantly increased (p<0.05) in the blast group compared to the sham group, thus indicating metabolic stress where the excitatory and inhibitory neurotransmitters are not properly balanced. Further, the Glu:GABA ratio in the cerebellum

Blast-induced traumatic brain injury (bTBI) remains a significant problem among military populations. Secondary injury responses such as oxidative stress, neuroinflammation, and neurodegeneration have been identified following blast exposure. The objective of this work was to identify the main contributors to secondary injury cascades by quantifying free amino acid concentrations in the hippocampus, cortex, and cerebellum at time points of 4, 12, and 48 hr following blast exposure. In this preliminary work, male Sprague Dawley rats (n = 4-5) were exposed to a single blast overpressure (17.27 +/- 1.99 psi) in the Virginia Tech Advanced Blast Simulator (ABS). Sham animals underwent all procedures, but were placed adjacent to the ABS (n = 4-5). Animals were euthanized at each time point following blast/sham and amino acids from

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