The authors have nothing to disclose.

1. Assembly of the Strike Device (Figure 1)
<ol>
	<li>Remove the plunger from a 1&#160;mL tuberculin syringe. Cut the barrel at the 1&#160;mL mark.</li>
	<li>Remove an aerosol barrier (3 mm height x 4 mm diameter) from a 200&#160;&#181;L pipette tip and use it as an impactor. Place the impactor inside the syringe barrel. Gently tap the barrel to move the impactor to the tip end, with the flat side covering the nozzle opening.</li>
	<li>Attach the barrel tip end to plastic tubing that is co...

<ol>
	<li>McKee, A. C., 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=The+first+NINDS/NIBIB+consensus+meeting+to+define+neuropathological+criteria+for+the+diagnosis+of+chronic+traumatic+encephalopathy.">The first NINDS/NIBIB consensus meeting to define neuropathological criteria for the diagnosis of chronic traumatic encephalopathy.</a> Acta Neuropathol. 131, 75-86 (2016).</li><li>Martland, H. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Punch+drunk.">Punch drunk.</a> JAMA. 91 (15), 1103-1107 (1928).</li><li>Millspaugh, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dementia+pugilistica.">Dementia pugilistica.</a> US Naval Med Bull. 35, 297-303 (1937).</li><li>Omalu, B. 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C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chronic+traumatic+encephalopathy:+where+are+we+and+where+are+we+going?.">Chronic traumatic encephalopathy: where are we and where are we going?.</a> Curr Neurol Neurosci Rep. 13 (12), 407 (2013).</li><li>McKee, A. C., 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=The+spectrum+of+disease+in+chronic+traumatic+encephalopathy.">The spectrum of disease in chronic traumatic encephalopathy.</a> Brain. 136 (Pt 1), 43-64 (2013).</li><li>Petraglia, A. L., 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=The+spectrum+of+neurobehavioral+sequelae+after+repetitive+mild+traumatic+brain+injury:+a+novel+mouse+model+of+chronic+traumatic+encephalopathy.">The spectrum of neurobehavioral sequelae after repetitive mild traumatic brain injury: a novel mouse model of chronic traumatic encephalopathy.</a> J Neurotrauma. 31 (13), 1211-1224 (2014).</li><li>Hirth, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drosophila+melanogaster+in+the+study+of+human+neurodegeneration.">Drosophila melanogaster in the study of human neurodegeneration.</a> CNS Neurol Disord Drug Targets. 9 (4), 504-523 (2010).</li><li>Littleton, J. 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=Ion+channels+and+synaptic+organization:+analysis+of+the+Drosophila+genome.">Ion channels and synaptic organization: analysis of the Drosophila genome.</a> Neuron. 26 (1), 35-43 (2000).</li><li>Appel, L. F., 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=The+Drosophila+Stubble-stubbloid+gene+encodes+an+apparent+transmembrane+serine+protease+required+for+epithelial+morphogenesis.">The Drosophila Stubble-stubbloid gene encodes an apparent transmembrane serine protease required for epithelial morphogenesis.</a> Proc Natl Acad Sci USA. 90 (11), 4937-4941 (1993).</li><li>Piyankarage, S. C., Featherstone, D. E., Shippy, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanoliter+hemolymph+sampling+and+analysis+of+individual+adult+Drosophila+melanogaster.">Nanoliter hemolymph sampling and analysis of individual adult Drosophila melanogaster.</a> Anal Chem. 84 (10), 4460-4466 (2012).</li><li>Katzenberger, R. J., 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=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 (44), E4152-E4159 (2013).</li><li>Barekat, A., 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=Using+Drosophila+as+an+integrated+model+to+study+mild+repetitive+traumatic+brain+injury.">Using Drosophila as an integrated model to study mild repetitive traumatic brain injury.</a> Sci Rep. 6, 25252 (2016).</li><li>Katzenberger, R. J., 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=A+Method+to+Inflict+Closed+Head+Traumatic+Brain+Injury+in+Drosophila.">A Method to Inflict Closed Head Traumatic Brain Injury in Drosophila.</a> J Vis Exp. (e52905), (2015).</li><li>Branson, K., Robie, A. A., Bender, J., Perona, P., Dickinson, M. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-throughput+ethomics+in+large+groups+of+Drosophila.">High-throughput ethomics in large groups of Drosophila.</a> Nat Methods. 6 (6), 451-457 (2009).</li><li>Straw, A. D., Dickinson, M. H., 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=Motmot,+an+open-source+toolkit+for+realtime+video+acquisition+and+analysis.">Motmot, an open-source toolkit for realtime video acquisition and analysis.</a> Source Code Biol Med. 4 (5), 1-10 (2009).</li><li>Talavage, T. M., 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=Functionally-detected+cognitive+impairment+in+high+school+football+players+without+clinically-diagnosed+concussion.">Functionally-detected cognitive impairment in high school football players without clinically-diagnosed concussion.</a> J Neurotrauma. 31 (4), 327-338 (2014).</li><li>Theadom, A., 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=Frequency+and+impact+of+recurrent+traumatic+brain+injury+in+a+population-based+sample.">Frequency and impact of recurrent traumatic brain injury in a population-based sample.</a> J Neurotrauma. 32 (10), 674-681 (2015).</li><li>Drobysheva, D., 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=An+optimized+method+for+histological+detection+of+dopaminergic+neurons+in+Drosophila+melanogaster.">An optimized method for histological detection of dopaminergic neurons in Drosophila melanogaster.</a> J Histochem Cytochem. 56 (12), 1049-1063 (2008).</li></ol>

Animal models that faithfully model CTE features, including neurophysiological alterations, neuropathological hallmarks, and neurobehavioral deficits, are essential for uncovering disease mechanisms and for developing diagnostic and therapeutic targets. It is understandable that no animal model of a human disease is perfect at mimicking all clinically relevant endpoints. However, we believe that a robust CTE model should satisfy the following three requirements: (1) the impact must be directly applied to a head that has ...

Chronic Traumatic Encephalopathy (CTE) has recently been recognized as a distinct neurodegenerative disorder, separate from other tauopathies such as Alzheimer&#39;s disease1. Unlike Alzheimer&#39;s disease and other common tauopathies-whose most important risk factors are advancing age and a family history of dementia,&#160;CTE, as indicated by its name, implies a close association with a history of brain trauma, most likely seen in contact sports athletes, such as boxers and football players, as well as in military veterans2,3,4,5. It is thought to be initiated by repeated concussive and subconcussive blows to the head. Patients may present symptoms and signs such as cognitive deficits, mood and behavior changes, and movement dysfunction, which overlap significantly with Alzheimer&#39;s disease, frontotemporal dementia, Lewy body dementia, and Parkinson&#39;s disease6. In contrast, post-mortem examinations of brain tissue reveal a distinct pattern of hyperphosphorylated tau accumulation surrounding small blood vessels at the depths of the cortical sulci, a pathognomonic feature not observed in the other degenerative conditions7. However, so far, very little is known about the pathogenesis leading to disease manifestation. This is in large part due to the lack of a faithful animal model - only recently have rodent models been generated5,8. These model organisms have the disadvantages of cost-intensive care and a relatively long life span, which are not well-suited for neurodegenerative disease studies.
Compared to mammalian counterparts, invertebrate animals such as Drosophila&#160;are an excellent alternative, with their cost-effective maintenance, extensive tools for dissecting genetic determinants, and relatively short lifespan9. Remarkably, fly and human brains share evolutionarily conserved molecular and cellular pathways, as well as anatomical similarities10,11,12. Two ingenious Drosophila models to study traumatic brain injury have been reported previously13,14. The first &#34;High Impact Trauma&#34; (HIT) device designed by Katzenberger and colleagues contained free-moving flies in a plastic vial that was tied to the free end of a metal spring13,15. When the plastic vial was tilted upright and released, it hit a polyurethane pad and imparted trauma to the flies as they bounced to the vial wall and rebounded. In contrast, Barekat and colleagues designed a different delivery method using the Omni Bead Ruptor-24 homogenizer platform14. Flies were incapacitated with CO2 and placed in a 2&#160;mL screwcap tube that was secured to the homogenizer and subjected to preprogrammed shaking conditions. One benefit of using the tissue homogenizer system is that the experimenter could modulate the intensity of injury, duration of injury, and number of injury bouts. However, both regimes suffer the same drawback: primary injuries to the head are randomly inflicted in terms of impact location and strength. In addition, both methods resulted in considerable mortality, caused by inevitable collateral damage to other parts of the body and internal organs. Here, we describe a novel method to induce mTBI in fruit flies. Our apparatus consists of a gas-propelled ballistic impactor. Compared to the existing Drosophila models14,15, our method has the unique advantage of delivering measurable impact, directed only at the free-moving fly head, thus allowing for the accurate control of various factors, such as impact severity, the time interval between impacts, and the total number of impacts sustained.

<table border="0" cellpadding="0" cellspacing="0" width="692">
	<tbody>
		<tr height="20">
			<td height="20" style="height:20px;width:216px;">Aerosol Barrier</td>
			<td style="width:151px;">USA Scientific</td>
			<td style="width:119px;">1120-8810</td>
			<td style="width:207px;">Used as an impactor</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:216px;">200 ul Pipette Tip</td>
			<td style="width:151px;">USA Scientific</td>
			<td style="width:119px;">1111-0706</td>
			<td>Used as a fly head holder</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:216px;">1000 ul Pipette Tip</td>
			<td style="width:151px;">USA Scientific</td>
			<td style="width:119px;">1122-1830</td>
			<td>Used as a connector</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:216px;">1 ml Tuberculin Syringe</td>
			<td style="width:151px;">Becton Dickinson</td>
			<td style="width:119px;">309625</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:216px;">60 mm Petri Dishes</td>
			<td style="width:151px;">Fisher Scientific</td>
			<td>FB0875713A</td>
			<td>Used as a tracking arenas</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:216px;">Flow Regulator</td>
			<td>Genesee Scientific</td>
			<td style="width:119px;">59-122WC</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:216px;">Standard Clamp Holder/stand</td>
			<td style="width:151px;">EISCO Scientific</td>
			<td style="width:119px;">CH0688</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:216px;">Fine Brush</td>
			<td style="width:151px;">Genesee Scientific</td>
			<td style="width:119px;">59-204</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:216px;">Flypad</td>
			<td style="width:151px;">Genesee Scientific</td>
			<td style="width:119px;">59-114</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:216px;">Sylgard Silicone Elastomer</td>
			<td style="width:151px;">Dow Corning</td>
			<td>4019862</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">CCD Camera</td>
			<td style="width:151px;">Microsoft&#160;</td>
			<td style="width:119px;">HD-5000</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Ctrax Walking Fly Tracker</td>
			<td style="width:151px;">Caltech</td>
			<td style="width:119px;">Ctrax 0.2.11</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:216px;">MATLAB Image Processing Toolbox</td>
			<td style="width:151px;">MATLAB</td>
			<td style="width:119px;">R2015b</td>
			<td></td>
		</tr>
	</tbody>
</table>

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.

To establish a CTE model using adult Drosophila, we determined the effectiveness of our device at inflicting a single closed-head injury. To eliminate the variations relating to genotype, sex, or age, we used 2-day-old Canton-S WT female flies in the experiment. We could easily control the strength of the impactor by regulating the flow rate of CO2 at a constant gas pressure of 100 kPa. Flies exposed to a single strike at the highest flow rate (15 L/min) exhibited mini...

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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.

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 ...

The overall goal of this novel procedure is to inflict closed traumatic brain injuries in the fruit fly, Drosophila, to establish a new chronic traumatic encephalopathy model. This method can help answer key questions in the chronic traumatic encephalopathy field, such as how the repetitive trauma induces neuron degeneration. The main advantage of this technique is that it delivers the repetitive impacts of adjustable strengths to the fly head directly without causing damage to other parts of the animal body.Real world demonstration of this method is critical as assembly of the device and fly loading steps are difficult to learn, because the Drosophila head is so small and it is important to apply the impact only to the head. To make the apparatus used to concuss or strike the fruit flies, first, make the impactor portion of the apparatus. Remove the plunger from a one milliliter polycarbonate tuberculin syringe and then cut the barrel at the one milliliter mark.For an impactor, use the aerosol barrier found on a 200 microliter pipette tip. This impactor should be three millimeters long and four millimeters in diameter. Then, pack the impactor into the syringe barrel with the flat side towards the nozzle.To provide force, attach the syringe barrel to a carbon dioxide flow regulator. The regulator must have an On Off toggle switch and good control of the gas flow rate. Then, clamp the barrel vertically to an iron stand, such that the impactor will fall to the bottom of the barrel.Next, make the fly holder. Start with a 200 microliter pipette tip. Cut the pipette's tip five millimeters from the small end to make a 8 millimeter diameter opening.A fly head will fit through this hole, but the thorax will not. Lastly, make a for the fly holder and impactor device. First, cut a one milliliter pipette tip 44 millimeters from the small opening.Second, cut a six millimeter length from the needle cover for a one milliliter syringe. Then, push the two together. Anesthetize a single, two-day old adult female fly using carbon dioxide.From the carbon dioxide pad, use a fine brush to gently transfer the fly into the holder. Then, gently tap the holder until the head protrudes from the tip. Of the proboscis is exposed, use a blunted, one milliliter syringe needle to gently tuck it back inside the tip.It is critical to keep the fly body, especially the mouth part, inside the holder. Otherwise, the fly may die from damage to the internal organs or from not being able to ingest food. Next, set the gas pressure to 100 kilopascals and adjust the flow as needed.Once the fly is loaded, tighten the holder to the syringe barrel using the connector, such that the fly head faces downward. Then, using the toggle switch, send a burst of gas that moves the impactor to strike the fly once and only once. Now, detach the fly holder and dump the fly back onto the carbon dioxide pad.Brush the fly into an empty vial until it recovers. Keep one fly per vial. The recovery takes only a few minutes.Repeat the process to test four flies per experimental group. Processing two groups, a test and a sham, should only take 20 to 30 minutes. Treat shams just like test animals, except do not include an aerosol barrier in the impactor tube.To track fly movements in a Petri dish, first, fill a six centimeter dish with transparent silicon elastomer to make the tracking arena. Leave a three millimeter gap between the silicon and the lid so that flies can walk freely in the gap, but not take flight. Beneath the tracking arena, have a white background.Next, anesthetize four flies from the same treatment group and place them in the arena. Let the flies acclimate for an hour to the arena, which should be fully lit and at about 22 degrees Celsius. Not hotter than room temperature.After an hour, use a charge-coupled device camera positioned above the arena to record the fly's activity for five minutes. After the five minute recording, anesthetize the flies in the arena and return them to a new home vial. Then, dispose of the arena.Later, analyze the recordings using the freely available Ctrax software. This software generates tracking data, which can be exported in a programmable language compatible format, such as the MATLAB format. From the data, calculate the distance traveled per frame, the mean walking distance for each fly, and the average distance traveled per fly.For statistical significance, expect to test about 100 flies per treatment group. To establish a chronic traumatic encephalopathy model, the effectiveness of a single, closed-head injury made by the impacting apparatus at different speeds was analyzed using two-day old Canton-S females. The gas pressure was held at 100 kilopascals.Flies exposed to a single strike at the highest tested flow rate, exhibited minimal external defects. Despite no clear evidence for external damage, injuries at a flow rate of 15 liters per minute were acutely lethal, resulting in less than a 10%survival within 24 hours. Survival increased with lower flow rates.One hundred percent survival was achieved at five liter per minute or less, so five liters per minute was selected as the standard for the model. Just after being struck, flies gradually recovered their mobility within four minutes. Recovery for the shams was about a minute quicker.Post-impact, video-assisted movement tracking was used to measure locomotive function. During the two days after the impact, locomotion slowly returned to normal. This evidence for gradual recovery is in line with CTE recovery in humans.To evaluate long term effects, a repetitive traumatic brain injury protocol of five strikes over five days was applied. Twenty days post-treatment, the locomotion of surviving members in each group was compared and the treated group clearly walked less. The lifespan of the treated group was also substantially reduced, with a median at 26 days compared to 37 days for controls.After its development, this technique paves the way for researchers in the field of mild repetitive traumatic brain injury to explore pathogenic mechanisms in the classic animal model Drosophila melanogaster. While attempting this procedure, it is important to remember to shield the proboscis, thorax and abdomen from direct impact by the aerosol barrier.

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8.1K visualizações.  Johns Hopkins University School of Medicine. The overall goal of this novel procedure is to inflict closed traumatic brain injuries in the fruit fly, Drosophila, to establish a new chronic traumatic encephalopathy model. This method can help answer key questions in the chronic traumatic encephalopathy field, such as how the repetitive trauma induces neuron degeneration. The main advantage of this technique is that it delivers the repetitive impacts of adjustable strengths to the fly head directly without causing damage to other parts of...