Multi‐echo susceptibility‐weighted imaging and histology of open‐field blast‐induced traumatic brain injury in a rat model

Abstract

Blast-induced traumatic brain injury is on the rise, predominantly as a result of the use of improvised explosive devices, resulting in undesirable neuropsychological dysfunctions, as demonstrated in both animals and humans. This study investigated the effect of open-field blast injury on the rat brain using multi-echo, susceptibility-weighted imaging (SWI). Multi-echo SWI provided phase maps with better signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR), making it a sensitive technique for brain injury. Male Sprague-Dawley rats were subjected to a survivable blast of 180 kPa. The visibility of blood vessels of varying sizes improved with multi-echo SWI. Reduced signal intensity from major vessels post-blast indicates increased deoxyhaemoglobin. Relative cerebral blood flow was computed from filtered phase SWI images using inferred changes in oxygen saturation from major blood vessels. Cerebral blood flow decreased significantly at day 3 and day 5 post-blast compared with that pre-blast. This was substantiated by the upregulation of β-amyloid precursor protein (β-APP), a marker of ischaemia, in the neuronal perikaya of the cerebral cortex, as observed by immunofluorescence, and in the cortical tissue by western blot analysis. Our findings indicate the presence of brain ischaemia in post-blast acute phase of injury with possible recovery subsequently. Our results from cerebrovascular imaging, histology and staining provide an insight into the ischaemic state of the brain post-blast and may be useful for prognosis and outcome.

Explosive-driven double-blast exposure: molecular, histopathological, and behavioral consequences

“…4 ). This is in line with other explosive 24 and shock tube driven 25 blast exposure studies in both mice and rats which report increased APP protein expression in various brain regions by western blot evaluation.…”

“…4). This is in line with other explosive 24 and shock tube driven 25 blast exposure studies in both mice and rats which report increased APP protein expression in various brain regions by western blot evaluation. There were no significant differences between 2 × B and Ctl rats in GFAP, Iba1, αII-spectrin (full length protein 240kD) and both the 150kD and 120kD spectrin breakdown product levels across all examined brain regions ( Figs.…”

Perspectives on Primary Blast Injury of the Brain: Translational Insights Into Non-inertial Low-Intensity Blast Injury

“…These nanoscale intracellular changes were anticipated based on the calculations of blast-induced phonon decay in brain water ( 51 ). Deployment-related open-field LIB models have reproduced other molecular alterations and behavioral abnormalities showing imputed correlations with ultrastructural findings and clinical abnormalities ( 52 – 58 ).…”

Moderate blast exposure alters gene expression and levels of amyloid precursor protein

“… 10 A similarly designed study reported that an open-field blast exposure (peak pressure = 26.1 psi) in rats led to decreased cerebral blood flow on days 3 and 5 postinjury and an increase in βAPP in the neuronal perikarya of the cerebral cortex. 9 Notably, most preclinical models use higher blast exposure levels to induce TBIs and examine central changes by analyzing brain samples directly. This method, however, is not feasible in clinical cohorts, where peripheral blood is predominantly studied.…”