A. Gomez, N. Alsbou, R. Wolf, M. Ahmad, M. Khandaker
University of Central Oklahoma,
United States
Keywords: traumatic brain injury, blast-induced TBI, dendritic branching, astrocytic activation, microglial activation, hippocampus, behavioral flexibility
Summary:
This study utilized a portable shock tube model, developed specifically to understand the effects of blast waves on intracranial pressure and traumatic brain injury (TBI) in mice. The system, created at the Oklahoma City Veteran Affairs Health Care System animal facilities, consists of a driver section connected to a longer driven section, separated by a polycarbonate membrane. The driver section is pressurized with gas, and when the pressure exceeds the membrane’s threshold, it bursts, producing a rapid gas expansion and generating a pressure waveform in the driven section. By varying membrane thickness, the bursting pressure and shock wave intensity can be controlled. Pressure transducers installed in both the driver and driven sections record the shock pressure profile. The developed blast simulator successfully generates TBI in mice that closely mimics injuries caused by explosive blasts in open-field conditions. The system produced shock waves corresponding to both mild and moderate TBI, validated through literature-consistent measurements of time to sternal recumbency. Behavioral assessments, including open field tests, revealed cognitive deficiencies in mice exposed to blast TBI. Notably, mice subjected to moderate blast waves exhibited significantly reduced activity levels, traveling 2.5 times less distance compared to non-blast-exposed mice. Brain sections from TBI and control animals were immunostained with GFAP to investigate reactive astrogliosis and morphological changes induced by TBI. Preliminary data indicated an increase in GFAP expression in the hippocampus at 24 hours post-TBI, suggesting an acute inflammatory response. These findings confirm that the shock tube setup effectively models TBI in mice and provides a reliable platform for studying blast-related brain injuries.