The WRAIR projectile concussive impact model of mild traumatic brain injury: re-design, testing and preclinical validation.
The WRAIR projectile concussive impact (PCI) model was developed for preclinical study of concussion. It represents a truly non-invasive closed-head injury caused by a blunt impact. The original design, however, has several drawbacks that limit the manipulation of injury parameters. The present study describes engineering advancements made to the PCI injury model including helmet material testing, projectile impact energy/head kinematics and impact location. Material testing indicated that among the tested materials, 'fiber-glass/carbon' had the lowest elastic modulus and yield stress for providing an relative high percentage of load transfer from the projectile impact, resulting in significant hippocampal astrocyte activation. Impact energy testing of small projectiles, ranging in shape and size, showed the steel sphere produced the highest impact energy and the most consistent impact characteristics. Additional tests confirmed the steel sphere produced linear and rotational motions on the rat's head while remaining within a range that meets the criteria for mTBI. Finally, impact location testing results showed that PCI targeted at the temporoparietal surface of the rat head produced the most prominent gait abnormalities. Using the parameters defined above, pilot studies were conducted to provide initial validation of the PCI model demonstrating quantifiable and significant increases in righting reflex recovery time, axonal damage and astrocyte activation following single and multiple concussions.
Brain Trauma Neuroprotection and Neurorestoration Branch, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research (WRAIR), 503 Robert Grant Avenue, Silver Spring, MD, 20910, USA, laiyee.leung@us.army.mil.
Lai Yee
LY
Leung
Zachary
Z
Larimore
Larry
L
Holmes
Casandra
C
Cartagena
Andrea
A
Mountney
Ying
Y
Deng-Bryant
Kara
K
Schmid
Deborah
D
Shear
Frank
F
Tortella
D016229:Amyloid beta-Peptides / Q000378:metabolism; D000818:Animals; D001369:Axons / Q000473:pathology; D001696:Biomechanical Phenomena; D001921:Brain / Q000378:metabolism; D001924:Brain Concussion / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D001930:Brain Injuries / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D002244:Carbon; D000077482:Carbon Fiber; D004195:Disease Models, Animal; D005684:Gait; D005898:Glass; D006260:Head Protective Devices; D008297:Male; D008422:Materials Testing; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results
D016229:Amyloid beta-Peptides; D000077482:Carbon Fiber; C009753:fiberglass; D002244:Carbon