This work was supported by National Institutes of Health grant, R01 AG033620 (BG) and by Robert Draper Technology Innovation Funding (DAW).

1. Construction of the HIT Device&#160;
<ol>
	<li>Attach the spring to the board using two clamps and four screws (Figure 1A). Center the clamps relative to the width of the board and butt them up against one another with the outer clamp flush with the edge of the board. Prior to attaching the clamps, bend them using pliers to fit tightly over the spring. 
	NOTE: See Table 1 for descriptions of the materials required for constructing the HIT device.&#160;The clamped end of the spring should be 1/8 inch (3.2 mm) from the edge of the board, and the free end should extend over the board by 3/4 inch (19 mm). Adjust the spring so that it lies parallel with the length of the board.</li>
	<li>Wrap the free end of the spring once around with the adhesive strip of Velcro loops. The outer edge of the Velcro should be flush with the end of the spring. The Velcro is important because it is used to secure the vial to the spring by creating a tight compression fitting. The Velcro also permits easy connection and removal of vials, allowing many vials to be processed in a short period of time.</li>
	<li>Place the ice bucket cover upside down, centered, tight against the wooden board. Orient the raised region of the ice bucket cover such that the long edge is parallel to the width of the board. Note that the raised region of the ice bucket is 1/2 inch (13&#160;mm)&#160;higher than the wooden board, so that when a vial is attached to the spring the spring will not lie flat on the board.</li>
	<li>Slide the whole device against a fixed object such as a wall, so that the ice bucket cover is wedged between the board and the object and does not move.</li>
	<li>Tape the paper protractor to the bottom of a cardboard fly vial tray and stand it on edge against the length of the board so that the 90&#176; mark is aligned with the spring when it is pulled back to a perfectly vertical position.</li>
</ol>
2. Operation of the HIT Device
<ol>
	<li>Place between 1 and 60 CO2-anesthetized flies in an empty vial and stopper the vial using a tight-fitting cotton ball.</li>
	<li>Confine the flies to the bottom 1 inch (2.5 cm) of the vial by pushing the cotton ball into the vial until it is 1 inch (2.5 cm)&#160;from the bottom. It is helpful to draw a line on the vial at the 1&#160;inch (2.5 cm)&#160;mark. Note that confining flies to larger or smaller regions of the vial can affect the severity of phenotypes.</li>
	<li>Wait 5 min for the flies to recover mobility from the CO2. Note that it is not known whether 5 min is sufficient to completely remove the effects of CO2.</li>
	<li>Insert the end of the spring into the vial until the inner edge of the Velcro is flush with the top of the vial (Figure 1B). When the spring is lying flat, 1 inch (2.5 cm)&#160;of the vial should overlap the raised region of the ice bucket cover. Vials can be reused many times.</li>
	<li>While sitting, hold the vial at the Velcro region using the thumb and forefinger of your left hand. Hold the board tight to the benchtop using your right hand. Alternatively, use C-clamps to hold the board tight to the benchtop.</li>
	<li>Pull the spring perfectly straight back to the desired angle. Release the spring. Allow the spring to come to a complete stop.</li>
	<li>Remove the vial from the spring and allow the flies to recover for &#8805;5 min. Subject the flies to another strike or transfer the flies to a vial with fly food. 
	NOTE: A variety of assays can be used to evaluate the phenotypic effects of strikes from the HIT device. For example, effects on longevity can be determined by analyzing the percent of flies that survive at times after injury, effects on brain morphology can be determined by histological analysis of the head, and effects on gene expression can be determined by quantitative analysis of mRNA levels10.</li>
	<li>Determine effects of the procedure that are not due to strikes by identically treating control flies that are not subjected to strikes. Wear hearing protection because the impact of the vial against the ice bucket cover produces a loud noise.</li>
</ol>

<ol>
	<li>Harrison-Felix, C. L., Whiteneck, G. G., Jha, A., DeVivo, M. J., Hammond, F. M., Hart, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mortality+over+four+decades+after+traumatic+brain+injury+rehabilitation:+A+retrospective+cohort+study.">Mortality over four decades after traumatic brain injury rehabilitation: A retrospective cohort study.</a> Arch Phys Med Rehabil. 90, 1506-1513 (2009).</li><li>Coronado, V. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surveillance+for+traumatic+brain+injury-related+deaths+&#8211;+United+States.">Surveillance for traumatic brain injury-related deaths &#8211; United States.</a> MMWR Surveill Summ. 60, 1-32 (1997).</li><li>Masel, B., DeWitt, D. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Traumatic+brain+injury:+A+disease+process,+not+an+event.">Traumatic brain injury: A disease process, not an event.</a> J. Neurotrauma. 27, 1529-1540 (2010).</li><li>Blennow, K., Hardy, J., Zetterberg, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+neuropathology+and+neurobiology+of+traumatic+brain+injury.">The neuropathology and neurobiology of traumatic brain injury.</a> Neuron. 76, 886-899 (2012).</li><li>Prins, M., Greco, T., Alexander, D., Giza, C. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+pathophysiology+of+traumatic+brain+injury+at+a+glance.">The pathophysiology of traumatic brain injury at a glance.</a> Disease Models Mech. 6, 1307-1315 (2013).</li><li>Menon, D. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Unique+challenges+in+clinical+trails+in+traumatic+brain+injury.">Unique challenges in clinical trails in traumatic brain injury.</a> Crit Care Med. 37, S129-S135 (2009).</li><li>Xiong, Y., Mahmood, A., Chopp, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Animal+models+of+traumatic+brain+injury.">Animal models of traumatic brain injury.</a> Nature Rev Neurosci. 14, 128-142 (2013).</li><li>Balsiger, Z., Leudkte, J., Mawer, S., Willey, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> HIT device high speed analysis. , (2014).</li><li>Davceva, N., Janevska, V., Illevski, B., Petrushevska, G., Popeska, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+occurrence+of+acute+subdural+haematoma+and+diffuse+axonal+injury+as+two+typical+acceleration+injuries.">The occurrence of acute subdural haematoma and diffuse axonal injury as two typical acceleration injuries.</a> J Forensic Leg Med. 19, 480-484 (2012).</li><li>Katzenberger, R. J., Loewen, C. A., Wassarman, D. R., Petersen, A. J., Ganetzky, B., Wassarman , D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Drosophila.+model+of+closed+head+traumatic+brain+injury.">A Drosophila. model of closed head traumatic brain injury.</a> Proc Natl Acad Sci USA. 110, E4152-E4159 (2013).</li><li>Fang, Y., Bonini, N. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Axon+degeneration+and+regeneration:+insights+from+Drosophila+.models+of+nerve+injury.">Axon degeneration and regeneration: insights from Drosophila .models of nerve injury.</a> Annu Rev Cell Biol. 28, 575-597 (2012).</li><li>Babcock, D. T., Ganetzky, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+improved+method+for+accurate+and+rapid+measurement+of+flight+performance+in+Drosophila.">An improved method for accurate and rapid measurement of flight performance in Drosophila.</a> J Vis Exp. (84), e51223 (2014).</li><li>Tully, T., Preat, T., Boynton, S. C., Vecchio, M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+dissection+of+consolidated+memory+in+Drosophila.">Genetic dissection of consolidated memory in Drosophila.</a> Cell. 79, 35-47 (1994).</li><li>Andretic, R., Shaw, P. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Essentials+of+sleep+recordings+in+Drosophila.:+moving+beyond+sleep+time.">Essentials of sleep recordings in Drosophila.: moving beyond sleep time.</a> Methods Enzymol. 393, 759-772 (2005).</li></ol>

We have no conflicts of interest to disclose.

The HIT device method is distinguished from other methods that inflict traumatic injury in flies&#160;by the fact that it causes closed head rather than penetrating TBI11. Furthermore, the HIT device method takes less time, effort, and skill to inflict TBI in many flies, so the method is more amenable than other methods to large-scale genetic screens. Lastly, the fact that primary injuries inflicted by the HIT device are not limited to the brain is both a limitation and an advantage. It is a limitation because...

An author's name was corrected in the publication of <a href="http://www.jove.com/video/52905">A Method to Inflict Closed Head Traumatic Brain Injury in Drosophila</a>. The second to last author's was spelled incorrectly. It has been updated from:
Barry Ganetky
to:
Barry Ganetzky

An author's name was corrected in the publication of <a href="http://www.jove.com/video/52905">A Method to Inflict Closed Head Traumatic Brain Injury in Drosophila</a>.

Erratum: A Method to Inflict Closed Head Traumatic Brain Injury in Drosophila

Traumatic brain injury (TBI) is defined as injury to the brain from an external mechanical force. Most commonly, TBI results from closed head forces such as blunt forces and inertial acceleration and deceleration forces that cause the brain to strike the inside of the skull. In the United States, it is estimated that 50,000 individuals die each year from TBI and 2.5-6.5 million individuals are living with the consequences of TBI, including debilitating physical, cognitive, and behavioral problems1,2. The consequences of TBI are not only due to primary mechanical injuries to the brain but also to secondary cellular and molecular injuries to the brain as well as other tissues that occur over time3-5. The development of approaches to diagnose and treat TBI has proven to be difficult because TBI is a complex disease process. The variable nature of primary injuries, human physiology, and environmental factors results in heterogeneous secondary injuries and pathologies. Underlying variable factors include the severity of the primary injury, the time between repetitive primary injuries, and the age and genotype of the individual. Understanding how each variable factor contributes to the consequences of TBI is likely to aid in the development of approaches to diagnose and treat TBI6,7.
Here we describe a method for inflicting closed head TBI in Drosophila melanogaster (fruit flies) that can be used to delineate the contribution of variable factors to the consequences of TBI. The method is based on an initial observation that intensely hitting the side of a fly culture vial against the palm of a hand caused wild-type flies to become temporarily incapacitated, a likely consequence of TBI. Thus, we constructed the High-Impact Trauma (HIT) device to recapitulate the acceleration and deceleration forces from the hand-hitting action. A high-speed movie shows that a single strike from the HIT device causes flies to contact the vial wall several times with their head and body8. To some extent, all contacts are likely to cause the fly brain to ricochet and deform against the head capsule, similar to what happens to humans in falls and car crashes9. Accordingly, flies treated with the HIT device display phenotypes consistent with brain injury, including temporary incapacitation followed by ataxia, gradual recovery of mobility, gene expression changes in the head, and progressive neurodegeneration in the brain10. Thus, the HIT device makes it possible to study TBI using the enormous arsenal of experimental tools and techniques developed for flies.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Zinc plated compression spring</td>
			<td>The Hillman&#160; Group</td>
			<td>540189</td>
			<td>9 7/8 in (length), 15/16 in (outer diameter), 0.12 in (wire size)</td>
		</tr>
		<tr>
			<td>Wooden board</td>
			<td></td>
			<td></td>
			<td>9 in (length), 6.5 in (width), 0.75 in (height)</td>
		</tr>
		<tr>
			<td>Clamps</td>
			<td>Sigma Electrical Manufacturing Corporation</td>
			<td>49822</td>
			<td>3.10 in (length), 0.68 in (width), 1.11 in (height), EMT Two Hole Straps, click on type for 1 inch steel EMT conduit</td>
		</tr>
		<tr>
			<td>Loop half of self-adhesive velcro</td>
			<td></td>
			<td></td>
			<td>3 in (length), (3/4 in width)</td>
		</tr>
		<tr>
			<td>Polyurethane ice bucket cover</td>
			<td>Fisher Scientific</td>
			<td>02-591-45</td>
			<td>9 1/8 in (length), 9 1/8 in (width), 1 1/4 in (height)</td>
		</tr>
		<tr>
			<td>Plastic fly vials</td>
			<td>Applied Scientific</td>
			<td>AS-510</td>
			<td>3 11/16 in (height), 1 1/16 in (inner diameter), 1 1/8 in (outer diameter)</td>
		</tr>
		<tr>
			<td>Large cotton balls</td>
			<td>Fisher Scientific</td>
			<td>22-456-883</td>
			<td></td>
		</tr>
		<tr>
			<td>Paper protractor</td>
			<td></td>
			<td></td>
			<td>10 in (diameter)</td>
		</tr>
	</tbody>
</table>

a method to inflict closed head traumatic brain injury in drosophila

Traumatic brain injury (TBI) affects millions of people each year, causing impairment of physical, cognitive, and behavioral functions and death. Studies using Drosophila have contributed important breakthroughs in understanding neurological processes. Thus, with the goal of understanding the cellular and molecular basis of TBI pathologies in humans, we developed the High Impact Trauma (HIT) device to inflict closed head TBI in flies. Flies subjected to the HIT device display phenotypes consistent with human TBI such as temporary incapacitation and progressive neurodegeneration. The HIT device uses a spring-based mechanism to propel flies against the wall of a vial, causing mechanical damage to the fly brain. The device is inexpensive and easy to construct, its operation is simple and rapid, and it produces reproducible results. Consequently, the HIT device can be combined with existing experimental tools and techniques for flies to address fundamental questions about TBI that can lead to the development of diagnostics and treatments for TBI. In particular, the HIT device can be used to perform large-scale genetic screens to understand the genetic basis of TBI pathologies.

We are interested in understanding why flies die shortly after primary injury. To quantify death, we determined the Mortality Index at 24 hr (MI24), which is the percentage of flies that died within 24 hr of the primary injury. Flies subjected to strikes from the HIT device were incubated at 25 &#176;C in a vial with fly food, and the number of dead flies was counted after 24 hr. We used this approach to identify factors that affect the MI24 and found that the MI24 is not affected by the ...

Watch this Scientific Journal Video about A Method to Inflict Closed Head Traumatic Brain Injury in Drosophila at JoVE.com

A Method to Inflict Closed Head Traumatic Brain Injury in Drosophila

Here we describe a method to inflict closed head traumatic brain injury (TBI) in Drosophila. This method provides a gateway to investigate the cellular and molecular mechanisms that underlie TBI pathologies using the vast array of experimental tools and techniques available for flies.

A Method to Inflict Closed Head Traumatic Brain Injury in Drosophila

Traumatic brain injury (TBI) affects millions of people each year, causing impairment of physical, cognitive, and behavioral functions and death. Studies ...

a-method-to-inflict-closed-head-traumatic-brain-injury-in-drosophila

Research

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11.4K Views.  University of Wisconsin-Madison. Here we describe a method to inflict closed head traumatic brain injury (TBI) in Drosophila. This method provides a gateway to investigate the cellular and molecular mechanisms that underlie TBI pathologies using the vast array of experimental tools and techniques available for flies.

Video: A Method to Inflict Closed Head Traumatic Brain Injury in Drosophila

Lateral Fluid Percussion: Model of Traumatic Brain Injury in Mice

Traumatic brain injury (TBI) research has attained renewed momentum due to the increasing awareness of head injuries, which result in morbidity and mortality. Based on the nature of primary injury following TBI, complex and heterogeneous secondary consequences result, which are followed by regenerative processes 1,2. Primary injury can be induced by a direct contusion to the brain from skull fracture or from shearing and stretching of tissue causing displacement of brain due to movement 3,4. The resulting hematomas and lacerations cause a vascular response 3,5, and the morphological and functional damage of the white matter leads to diffuse axonal injury 6-8. Additional secondary changes commonly seen in the brain are edema and increased intracranial pressure 9. Following TBI there are microscopic alterations in biochemical and physiological pathways involving the release of excitotoxic neurotransmitters, immune mediators and oxygen radicals 10-12, which ultimately result in long-term neurological disabilities 13,14. Thus choosing appropriate animal models of TBI that present similar cellular and molecular events in human and rodent TBI is critical for studying the mechanisms underlying injury and repair.
Various experimental models of TBI have been developed to reproduce aspects of TBI observed in humans, among them three specific models are widely adapted for rodents: fluid percussion, cortical impact and weight drop/impact acceleration 1. The fluid percussion device produces an injury through a craniectomy by applying a brief fluid pressure pulse on to the intact dura. The pulse is created by a pendulum striking the piston of a reservoir of fluid. The percussion produces brief displacement and deformation of neural tissue 1,15. Conversely, cortical impact injury delivers mechanical energy to the intact dura via a rigid impactor under pneumatic pressure 16,17. The weight drop/impact model is characterized by the fall of a rod with a specific mass on the closed skull 18. Among the TBI models, LFP is the most established and commonly used model to evaluate mixed focal and diffuse brain injury 19. It is reproducible and is standardized to allow for the manipulation of injury parameters. LFP recapitulates injuries observed in humans, thus rendering it clinically relevant, and allows for exploration of novel therapeutics for clinical translation 20.
We describe the detailed protocol to perform LFP procedure in mice. The injury inflicted is mild to moderate, with brain regions such as cortex, hippocampus and corpus callosum being most vulnerable. Hippocampal and motor learning tasks are explored following LFP.

Lateral fluid percussion (LFP), an established model of traumatic brain injury in mice, is demonstrated. LFP fulfills three major criteria for animal models: validity, reliability and clinical relevance. The procedure, consisting of surgical craniotomy, fixation of hub followed by induction of injury, resulting in focal and diffuse injuries, is described.

Traumatic brain injury (TBI) research has attained renewed momentum due to the increasing awareness of head injuries, which result in morbidity and ...

Investigations on Alterations of Hippocampal Circuit Function Following Mild Traumatic Brain Injury

Traumatic Brain Injury (TBI) afflicts more than 1.7 million people in the United States each year and even mild TBI can lead to persistent neurological impairments 1. Two pervasive and disabling symptoms experienced by TBI survivors, memory deficits and a reduction in seizure threshold, are thought to be mediated by TBI-induced hippocampal dysfunction 2,3. In order to demonstrate how altered hippocampal circuit function adversely affects behavior after TBI in mice, we employ lateral fluid percussion injury, a commonly used animal model of TBI that recreates many features of human TBI including neuronal cell loss, gliosis, and ionic perturbation 4-6.
	Here we demonstrate a combinatorial method for investigating TBI-induced hippocampal dysfunction. Our approach incorporates multiple ex vivo physiological techniques together with animal behavior and biochemical analysis, in order to analyze post-TBI changes in the hippocampus. We begin with the experimental injury paradigm along with behavioral analysis to assess cognitive disability following TBI. Next, we feature three distinct ex vivo recording techniques: extracellular field potential recording, visualized whole-cell patch-clamping, and voltage sensitive dye recording. Finally, we demonstrate a method for regionally dissecting subregions of the hippocampus that can be useful for detailed analysis of neurochemical and metabolic alterations post-TBI.
	These methods have been used to examine the alterations in hippocampal circuitry following TBI and to probe the opposing changes in network circuit function that occur in the dentate gyrus and CA1 subregions of the hippocampus (see Figure 1). The ability to analyze the post-TBI changes in each subregion is essential to understanding the underlying mechanisms contributing to TBI-induced behavioral and cognitive deficits. 
	The multi-faceted system outlined here allows investigators to push past characterization of phenomenology induced by a disease state (in this case TBI) and determine the mechanisms responsible for the observed pathology associated with TBI.

A multi-faceted approach to investigating functional changes to hippocampal circuitry is explained. Electrophysiological techniques are described along with the injury protocol, behavioral testing and regional dissection method. The combination of these techniques can be applied in similar fashion for other brain regions and scientific questions.

Traumatic Brain Injury (TBI) afflicts more than 1.7 million people in the United States each year and even mild TBI can lead to persistent neurological ...

A Novel Method to Model Chronic Traumatic Encephalopathy in Drosophila

Chronic Traumatic Encephalopathy (CTE) is an established neurodegenerative disease that is closely associated with exposure to repetitive mild Traumatic Brain Injury (mTBI). The mechanisms responsible for its complex pathological changes remain largely elusive, despite a recent consensus to define the neuropathological criteria. Here, we describe a novel method to develop a model of CTE in Drosophila melanogaster&#160;(Drosophila&#160;)&#160;in an attempt to identify the key genes and pathways that lead to the characteristic hyperphosphorylated tau accumulation and neuronal death in the brain. Adjustable-strength impacts to inflict mild closed injury are delivered directly to the fly head, subjecting the head to rapid acceleration and deceleration. Our method eliminates the potential problems inherent with other Drosophila mTBI models (e.g.,animal death might be induced by damage to other parts of the body or to internal organs). The less labor- and cost-intensive animal care, short life span, and extensive genetic tools make the fruit fly ideal to study CTE pathogenesis and make it possible to perform large-scale, genome-wide forward genetic and pharmacological screens. We anticipate that the ongoing characterization of the model will generate important mechanistic insights on disease prevention and therapeutic approaches.

A Novel Method to Model Chronic Traumatic Encephalopathy in Drosophila

Here, we describe a new approach to inflict closed-head traumatic brain injury in Drosophila melanogaster. Our method has the advantage of directly delivering repetitive impacts with adjustable strength to the head alone. Further exploration of the invertebrate system will help to illuminate the pathogenesis of chronic traumatic encephalopathy.

Chronic Traumatic Encephalopathy (CTE) is an established neurodegenerative disease that is closely associated with exposure to repetitive mild Traumatic ...

Stereotactic Atlas-Guided Laser Capture Microdissection of Brain Regions Affected by Traumatic Injury

The ability to isolate specific brain regions of interest can be impeded in tissue disassociation techniques that do not preserve their spatial distribution. Such techniques also potentially skew gene expression analysis because the process itself can alter expression patterns in individual cells. Here we describe a laser capture microdissection (LCM) method to selectively collect specific brain regions affected by traumatic brain injury (TBI) by using a modified Nissl (cresyl violet) staining protocol and the guidance of a rat brain atlas. LCM provides access to brain regions in their native positions and the ability to use anatomical landmarks for identification of each specific region. To this end, LCM has been used previously to examine brain region specific gene expression in TBI. This protocol allows examination of TBI-induced alterations in gene and microRNA expression in distinct brain areas within the same animal. The principles of this protocol can be amended and applied to a wide range of studies examining genomic expression in other disease and/or animal models.

We describe the use of laser capture microdissection to obtain samples of distinct cell populations from different brain regions for gene and microRNA analysis. This technique allows the study of differential effects of traumatic brain injury in specific regions of the rat brain.

The ability to isolate specific brain regions of interest can be impeded in tissue disassociation techniques that do not preserve their spatial ...

A Novel In Vitro Model of Blast Traumatic Brain Injury

Traumatic brain injury is a leading cause of death and disability in military and civilian populations. Blast traumatic brain injury results from the detonation of explosive devices, however, the mechanisms that underlie the brain damage resulting from blast overpressure exposure are not entirely understood and are believed to be unique to this type of brain injury. Preclinical models are crucial tools that contribute to better understand blast-induced brain injury. A novel in vitro blast TBI model was developed using an open-ended shock tube to simulate real-life open-field blast waves modelled by the Friedlander waveform. C57BL/6N mouse organotypic hippocampal slice cultures were exposed to single shock waves and the development of injury was characterized up to 72 h using propidium iodide, a well-established fluorescent marker of cell damage that only penetrates cells with compromised cellular membranes. Propidium iodide fluorescence was significantly higher in the slices exposed to a blast wave when compared with sham slices throughout the duration of the protocol. The brain tissue injury is very reproducible and proportional to the peak overpressure of the shock wave applied.

A Novel In Vitro Model of Blast Traumatic Brain Injury

This paper describes a novel model of primary blast traumatic brain injury. A compressed-air driven shock tube is used to expose in vitro mouse hippocampal slice cultures to a single shock wave. This is a simple and rapid protocol generating a reproducible brain tissue injury with a high throughput.

Traumatic brain injury is a leading cause of death and disability in military and civilian populations. Blast traumatic brain injury results from the ...

Effects of Blast-induced Neurotrauma on Pressurized Rodent Middle Cerebral Arteries

Though there have been studies on the histopathological and behavioral effects of blast exposure, fewer have been dedicated to blast&#39;s cerebral vascular effects. Impact (i.e., non-blast) traumatic brain injury (TBI) is known to decrease pressure autoregulation in the cerebral vasculature in both humans and experimental animals. The hypothesis that blast-induced traumatic brain injury (bTBI), like impact TBI, results in impaired cerebral vascular reactivity was tested by measuring myogenic dilatory responses to reduced intravascular pressure in rodent middle cerebral arterial (MCA) segments from rats subjected to mild bTBI using an Advanced Blast Simulator (ABS) shock tube. Adult, male Sprague-Dawley rats were anesthetized, intubated, ventilated and prepared for Sham bTBI (identical manipulation and anesthesia except for blast injury) or mild bTBI. Rats were randomly assigned to receive Sham bTBI or mild bTBI followed by sacrifice 30 or 60 min post-injury. Immediately after bTBI, righting reflex (RR) suppression times were assessed, euthanasia at the time points post-injury was completed, the brain was harvested and the individual MCA segments were collected, mounted and pressurized. As the intraluminal pressure perfused through the arterial segments was reduced in 20 mmHg increments from 100 to 20 mmHg, MCA diameters were measured and recorded. With decreasing intraluminal pressure, MCA diameters steadily increased significantly above baseline in the Sham bTBI groups while MCA dilator responses were significantly reduced (p &#60; 0.05) in both bTBI groups as evidenced by the impaired, smaller MCA diameters recorded for the bTBI groups. In addition, RR suppression in the bTBI groups was significantly (p &#60; 0.05) higher than in the Sham bTBI groups. MCA&#39;s collected from the Sham bTBI groups exhibited typical vasodilatory properties to decreases in intraluminal pressure while MCA&#39;s collected following bTBI exhibited significantly impaired myogenic vasodilatory responses to reduced pressure that persisted for at least 60 min after bTBI.

Here, we present a protocol to describe methods for ex vivo vascular reactivity determination following a primary blast traumatic brain injury (bTBI) using isolated, pressurized, rodent middle cerebral arterial (MCA) segments. bTBI induction is accomplished using a shock tube, also known as an Advanced Blast Simulator (ABS) device.

Though there have been studies on the histopathological and behavioral effects of blast exposure, fewer have been dedicated to blast&#39;s cerebral ...

Investigating Alterations in Caecum Microbiota After Traumatic Brain Injury in Mice

Increasing evidence shows that the microbiota-gut-brain axis plays an important role in the pathogenesis of brain diseases. Several studies also demonstrate that traumatic brain injuries cause changes to the gut microbiota. However, mechanisms underlying the bidirectional regulation of the brain-gut axis remain unknown. Currently, few models exist for studying the changes in gut microbiota after traumatic brain injury. Therefore, the presented study combines protocols for inducing traumatic brain injury using a lateral fluid percussion device and analysis of caecum samples following injury for investigating alterations in the gut microbiome. Alterations of the gut microbiota composition after traumatic brain injury are determined using 16S-rDNA sequencing. This protocol provides an effective method for studying the relationships between enteric microorganisms and traumatic brain injury.

Presented here is a protocol to induce diffuse traumatic brain injury using a lateral fluid percussion device followed by the collection of the caecum content for gut microbiome analysis.

Increasing evidence shows that the microbiota-gut-brain axis plays an important role in the pathogenesis of brain diseases. Several studies also ...

Low-intensity Blast Wave Model for Preclinical Assessment of Closed-head Mild Traumatic Brain Injury in Rodents

Traumatic brain injury (TBI) is a large-scale public health problem. Mild TBI is the most prevalent form of neurotrauma and accounts for a large number of medical visits in the United States. There are currently no FDA-approved treatments available for TBI. The increased incidence of military-related, blast-induced TBI further accentuates the urgent need for effective TBI treatments. Therefore, new preclinical TBI animal models that recapitulate aspects of human blast-related TBI will greatly advance the research efforts into the neurobiological and pathophysiological processes underlying mild to moderate TBI as well as the development of novel therapeutic strategies for TBI.
Here we present a reliable, reproducible model for the investigation of the molecular, cellular, and behavioral effects of mild to moderate blast-induced TBI. We describe a step-by-step protocol for closed-head, blast-induced mild TBI in rodents using a bench-top setup consisting of a gas-driven shock tube equipped with piezoelectric pressure sensors to ensure consistent test conditions. The benefits of the setup that we have established are its relative low-cost, ease of installation, ease of use and high-throughput capacity. Further advantages of this non-invasive TBI model include the scalability of the blast peak overpressure and the generation of controlled reproducible outcomes. The reproducibility and relevance of this TBI model has been evaluated in a number of downstream applications, including neurobiological, neuropathological, neurophysiological and behavioral analyses, supporting the use of this model for the characterization of processes underlying the etiology of mild to moderate TBI.

We present here a protocol of a blast wave model for rodents to investigate neurobiological and pathophysiological effects of mild to moderate traumatic brain injury. We established a gas-driven, bench-top setup equipped with pressure sensors allowing for reliable and reproducible generation of blast-induced mild to moderate traumatic brain injury.

Traumatic brain injury (TBI) is a large-scale public health problem. Mild TBI is the most prevalent form of neurotrauma and accounts for a large number of ...

Systems Analysis of the Neuroinflammatory and Hemodynamic Response to Traumatic Brain Injury

Mild traumatic brain injuries (mTBIs) are a significant public health problem. Repeated exposure to mTBI can lead to cumulative, long-lasting functional deficits. Numerous studies by our group and others have shown that mTBI stimulates cytokine expression and activates microglia, decreases cerebral blood flow and metabolism, and impairs cerebrovascular reactivity. Moreover, several works have reported an association between derangements in these neuroinflammatory and hemodynamic markers and cognitive impairments. Herein we detail methods to characterize the neuroinflammatory and hemodynamic tissue response to mTBI in mice. Specifically, we describe how to perform a weight-drop model of mTBI, how to longitudinally measure cerebral blood flow using a non-invasive optical technique called diffuse correlation spectroscopy, and how to perform a Luminex multiplexed immunoassay on brain tissue samples to quantify cytokines and immunomodulatory phospho-proteins (e.g., within the MAPK and NF&#954;B pathways) that respond to and regulate activity of microglia and other neural immune cells. Finally, we detail how to integrate these data using a multivariate systems analysis approach to understand the relationships between all of these variables. Understanding the relationships between these physiologic and molecular variables will ultimately enable us to identify mechanisms responsible for mTBI.

This protocol presents methods to characterize the neuroinflammatory and hemodynamic response to mild traumatic brain injury and to integrate these data as part of a multivariate systems analysis using partial least squares regression.

Mild traumatic brain injuries (mTBIs) are a significant public health problem. Repeated exposure to mTBI can lead to cumulative, long-lasting functional ...

Electromagnetic Controlled Closed-Head Model of Mild Traumatic Brain Injury in Mice

Highly reproducible animal models of traumatic brain injury (TBI), with well-defined pathologies, are needed for testing therapeutic interventions and understanding the mechanisms of how a TBI alters brain function. The availability of multiple animal models of TBI is necessary to model the different aspects and severities of TBI seen in people. This manuscript describes the use of a midline closed head injury (CHI) to develop a mouse model of mild TBI. The model is considered mild because it does not produce structural brain lesions based on neuroimaging or gross neuronal loss. However, a single impact creates enough pathology that cognitive impairment is measurable at least 1 month after injury. A step-by-step protocol to induce a CHI in mice using a stereotaxically guided electromagnetic impactor is defined in the paper. The benefits of the mild midline CHI model include the reproducibility of the injury-induced changes with low mortality. The model has been temporally characterized up to 1 year after the injury for neuroimaging, neurochemical, neuropathological, and behavioral changes. The model is complementary to open skull models of controlled cortical impact using the same impactor device. Thus, labs can model both mild diffuse TBI and focal moderate-to-severe TBI with the same impactor.

The protocol describes mild traumatic brain injury in a mouse model. In particular, a step-by-step protocol to induce a mild midline closed head injury and the characterization of the animal model is fully explained.

Highly reproducible animal models of traumatic brain injury (TBI), with well-defined pathologies, are needed for testing therapeutic interventions and ...