Spectrin Breakdown Products in the Investigation
of Blast Induced Traumatic Brain Injury

Abstract

Blast injury has become the ‘signature injury’ of modern conflict, and there is increasing concern that within this injured population mild to severe Traumatic Brain Injury (TBI) is becoming more prevalent. TBI is difficult to diagnose using conventional diagnostic
methods.
One component of a blast, the blast wave, has been associated with TBI. This has led to a suspicion of a subset of blast‐exposed personnel who appear uninjured, but then develop TBI. Consequently, there has been much research into the use biomarkers for diagnosis
and prognosis of TBI.
αII-Spectrin is a 240kDa cytoskeletal protein found in the cell membrane of neurons. Spectrin is irreversibly cleaved by the action of the proteases Calpain and Caspase,
producing 145kDa and 120kDa Spectrin Breakdown Product (SBDP) respectively.
The aim of this study was to see if a blast wave to the head would produce SBDPs of interest and if they could be found in the Cerebrospinal Fluid (CSF) and plasma.
Terminally anaesthetised rats were subjected to a blast wave to the head; an equally sized control group was used. Blood was periodically sampled and at eight hours post‐injury the brains, CSF and plasma were collected. Western Blot Gel Electrophoresis was used to identify SBDP in brain homogenate, CSF and plasma.
SBDP 145 and 120 were identified in brain homogenate and in plasma in blast and control groups, but there were no significant differences between groups. This suggests that blast exposure per se does not specifically lead to elevations in SBDP. It was not possible to reliably assess SBDPs in CSF due to blood contamination.
This study did not provide evidence that SBDPs are a reliable indicator of any TBI caused by a blast wave to the head in the acute phase, although they may have a role in polytrauma.