This work was supported by R01 NS105807/NS/NINDS NIH HHS/United States and CURE based on a grant CURE received from the United States Army Medical Research and Materiel Command, Department of Defense (DoD), through the Psychological Health and Traumatic Brain Injury Research Program under Award No. W81XWH-15-2-0069. Ivan Zuidhoek is greatly appreciated for proofreading the manuscript.

<ol><li>Christensen, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Long-term+risk+of+epilepsy+after+traumatic+brain+injury+in+children+and+young+adults%3A+a+population-based+cohort+study%5BTitle%5D)+AND+%22Lancet%22%5BJournal%5D)">Long-term risk of epilepsy after traumatic brain injury in children and young adults: a population-based cohort study.</a> Lancet. 373 (9669), 1105-1110 (2009).</li>
<li>Lowenstein, D. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Epilepsy+after+head+injury%3A+an+overview%5BTitle%5D)+AND+%22Epilepsia%22%5BJournal%5D)">Epilepsy after head injury: an overview.</a> Epilepsia. 50, Suppl 2 4-9 (2009).</li>
<li>Ferguson, P. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+population-based+study+of+risk+of+epilepsy+after+hospitalization+for+traumatic+brain+injury%5BTitle%5D)+AND+%22Epilepsia%22%5BJournal%5D)">A population-based study of risk of epilepsy after hospitalization for traumatic brain injury.</a> Epilepsia. 51 (5), 891-898 (2010).</li>
<li>Abou-Abbass, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Epidemiology+and+clinical+characteristics+of+traumatic+brain+injury+in+Lebanon%3A+A+systematic+review%5BTitle%5D)+AND+%22Medicine+%28Baltimore%29%22%5BJournal%5D)">Epidemiology and clinical characteristics of traumatic brain injury in Lebanon: A systematic review.</a> Medicine (Baltimore). 95 (47), 5342(2016).</li>
<li>Management of Concussion/mTBI Working Group. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((VA%2FDoD+Clinical+Practice+Guideline+for+Management+of+Concussion%2FMild+Traumatic+Brain+Injury%5BTitle%5D)+AND+%22The+Journal+of+Rehabilitation+Research+and+Development%22%5BJournal%5D)">VA/DoD Clinical Practice Guideline for Management of Concussion/Mild Traumatic Brain Injury.</a> The Journal of Rehabilitation Research and Development. 46 (6), 1-68 (2009).</li>
<li>Piccenna, L., Shears, G., O'Brien, T. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Management+of+post-traumatic+epilepsy%3A+An+evidence+review+over+the+last+5+years+and+future+directions%5BTitle%5D)+AND+%22Epilepsia+Open%22%5BJournal%5D)">Management of post-traumatic epilepsy: An evidence review over the last 5 years and future directions.</a> Epilepsia Open. 2 (2), 123-144 (2017).</li>
<li>Loscher, W., Brandt, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Prevention+or+modification+of+epileptogenesis+after+brain+insults%3A+experimental+approaches+and+translational+research%5BTitle%5D)+AND+%22Pharmacological+Reviews%22%5BJournal%5D)">Prevention or modification of epileptogenesis after brain insults: experimental approaches and translational research.</a> Pharmacological Reviews. 62 (4), 668-700 (2010).</li>
<li>Ostergard, T., Sweet, J., Kusyk, D., Herring, E., Miller, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Animal+models+of+post-traumatic+epilepsy%5BTitle%5D)+AND+%22Journal+of+Neuroscience+Methods%22%5BJournal%5D)">Animal models of post-traumatic epilepsy.</a> Journal of Neuroscience Methods. 272, 50-55 (2016).</li>
<li>Shandra, O., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Repetitive+Diffuse+Mild+Traumatic+Brain+Injury+Causes+an+Atypical+Astrocyte+Response+and+Spontaneous+Recurrent+Seizures%5BTitle%5D)+AND+%22Journal+of+Neuroscience%22%5BJournal%5D)">Repetitive Diffuse Mild Traumatic Brain Injury Causes an Atypical Astrocyte Response and Spontaneous Recurrent Seizures.</a> Journal of Neuroscience. 39 (10), 1944-1963 (2019).</li>
<li>Foda, M. A., Marmarou, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+new+model+of+diffuse+brain+injury+in+rats.+Part+II%3A+Morphological+characterization%5BTitle%5D)+AND+%22Journal+of+Neurosurgery%22%5BJournal%5D)">A new model of diffuse brain injury in rats. Part II: Morphological characterization.</a> Journal of Neurosurgery. 80 (2), 301-313 (1994).</li>
<li>Marmarou, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+new+model+of+diffuse+brain+injury+in+rats.+Part+I%3A+Pathophysiology+and+biomechanics%5BTitle%5D)+AND+%22Journal+of+Neurosurgery%22%5BJournal%5D)">A new model of diffuse brain injury in rats. Part I: Pathophysiology and biomechanics.</a> Journal of Neurosurgery. 80 (2), 291-300 (1994).</li>
<li>Paxinos, G., Keith, B. J., Franklin, M. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aPaxinos%2C+G+%22The+Mouse+Brain+in+Stereotaxic+Coordinates%22">The Mouse Brain in Stereotaxic Coordinates</a>. , Elsevier Science. (2007).</li>
<li>Shandra, O., Robel, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Imaging+and+Manipulating+Astrocyte+Function+In+Vivo+in+the+Context+of+CNS+Injury%5BTitle%5D)+AND+%22Methods+in+Molecular+Biology%22%5BJournal%5D)">Imaging and Manipulating Astrocyte Function In Vivo in the Context of CNS Injury.</a> Methods in Molecular Biology. 1938, 233-246 (2019).</li>
<li>Pitkanen, A., Immonen, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Epilepsy+related+to+traumatic+brain+injury%5BTitle%5D)+AND+%22Neurotherapeutics%22%5BJournal%5D)">Epilepsy related to traumatic brain injury.</a> Neurotherapeutics. 11 (2), 286-296 (2014).</li>
<li>Kharatishvili, I., Nissinen, J. P., McIntosh, T. K., Pitkanen, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+model+of+posttraumatic+epilepsy+induced+by+lateral+fluid-percussion+brain+injury+in+rats%5BTitle%5D)+AND+%22Neuroscience%22%5BJournal%5D)">A model of posttraumatic epilepsy induced by lateral fluid-percussion brain injury in rats.</a> Neuroscience. 140 (2), 685-697 (2006).</li>
<li>Pitkanen, A., Bolkvadze, T., Immonen, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Anti-epileptogenesis+in+rodent+post-traumatic+epilepsy+models%5BTitle%5D)+AND+%22Neuroscience+Letters%22%5BJournal%5D)">Anti-epileptogenesis in rodent post-traumatic epilepsy models.</a> Neuroscience Letters. 497 (3), 163-171 (2011).</li>
<li>Gades, N. M., Danneman, P. J., Wixson, S. K., Tolley, E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+magnitude+and+duration+of+the+analgesic+effect+of+morphine%2C+butorphanol%2C+and+buprenorphine+in+rats+and+mice%5BTitle%5D)+AND+%22Journal+of+the+American+Association+for+Laboratory+Animal+Science%22%5BJournal%5D)">The magnitude and duration of the analgesic effect of morphine, butorphanol, and buprenorphine in rats and mice.</a> Journal of the American Association for Laboratory Animal Science. 39 (2), 8-13 (2000).</li>
</ol>

The authors have nothing to disclose.

In contrast to CCI and FPI models inducing either focal or combination of focal and diffuse injury, the model of repetitive diffuse TBI described in this protocol allows for the induction of diffuse injury in the absence of focal brain injury and does not require scalp or cranial openings and the associated inflammation. An added benefit of the absence of craniectomy in this model is that it allows to not only implant the electrodes for chronic continuous EEG recording, but also the creation of a thinned-skull cranial wi...

Every year TBI affects an estimated 60 million people worldwide. Impacted individuals are at higher risk of developing epilepsy, which can manifest years after the initial injury. Though severe TBIs are associated with a higher risk of epilepsy, even mild TBI increases an individual&rsquo;s chance of developing epilepsy1,2,3,4. All TBIs can be classified as focal, diffuse, or a combination of both. Diffuse brain injury, present in many if not all TBIs, is a result of brain tissues of different densities shearing against each other due to acceleration-deceleration and rotational forces. By definition, diffuse injury only occurs in isolation in mild/concussive non-penetrating brain injury, in which no brain lesions are visible on computed tomography scans5.
There are currently two critical problems in the management of patients who have, or are at risk of, developing post-traumatic epilepsy (PTE). The first is that once PTE has manifested, seizures are resistant to available anti-epileptic drugs (AEDs)6. Secondly, AEDs are equally ineffective at preventing epileptogenesis, and there are no effective alternative therapeutic approaches. In order to address this deficit and find better therapeutic targets and candidates for treatment, it will be necessary to explore new cellular and molecular mechanisms at the root of PTE6.
One of the prominent features of post-traumatic epilepsy is the latent period between the initial traumatic event and the onset of spontaneous, unprovoked, recurrent seizures. The events that occur within this temporal window are a natural focus for researchers, because this time window might allow treatment and prevention of PTE altogether. Animal models are most commonly used for this research because they offer several distinct benefits, not the least of which is that continuous monitoring of human patients would be both impractical and costly over such potentially long spans of time. Additionally, cellular and molecular mechanisms at the root of epileptogenesis can only be explored in animal models.
Animal models with spontaneous post-traumatic seizures and epilepsy are preferred over models where seizures are induced after TBI by less physiologically relevant means, such as by chemoconvulsants or electric stimulation acutely, chronically, or by kindling. Spontaneous post-traumatic seizure models test how TBI modifies the healthy brain network leading to epileptogenesis. Studies using additional stimulation after TBI assess how exposure to TBI reduces seizure threshold and affects susceptibility to seizures. The advantages of animal models with seizures induced chemically or with electric stimulation are in testing the specific mechanisms of refractoriness to AEDs and the efficacy of existing and novel AEDs. Yet, the degree of relevance and translation of these data to humans may be ambiguous7 due to the following: 1) seizure mechanisms may be different from those induced by TBI alone; 2) not all of these models lead to spontaneous seizures7; 3) lesions created by the convulsant agent itself, with the cannula required for its delivery, or by stimulating electrode placement in depth structures (e.g., the hippocampus or amygdala) can already cause increased seizure susceptibility and even hippocampal epileptiform field potentials7. Furthermore, some convulsant agents (i.e., kainic acid) produce direct hippocampal lesions and sclerosis, which is not typical after diffuse TBI.
Until recently, only two animal models of post-traumatic epilepsy existed: controlled cortical impact (CCI, focal) or fluid percussion injury (FPI, focal and diffuse)8. Both models result in large focal lesions alongside tissue loss, hemorrhage, and gliosis in rodents8. These models mimic post-traumatic epilepsy induced by large focal lesions. A recent study demonstrated that repeated (3x) diffuse TBI is sufficient for the development of spontaneous seizures and epilepsy in mice even in the absence of focal lesions9, adding a third rodent PTE model with confirmed spontaneous recurrent seizures. This new model mimics cellular and molecular changes induced by diffuse TBI, better representing the human population with mild, concussive TBIs. In this model, the latent period of three weeks or more before seizure onset and the emergence of late, spontaneous, recurrent seizures allows for investigating the root causes of post-traumatic epileptogenesis, testing the efficacy of preventive approaches and new therapeutic candidates after seizure onset, and has potential for the development of biomarkers of post-traumatic epileptogenesis because approximately half of the animals develop post-traumatic epilepsy.
The choice of animal model for the study of post-traumatic epilepsy depends on the scientific question, the type of brain injury investigated, and what tools will be used to determine the underlying cellular and molecular mechanisms. Ultimately, any model of post-traumatic epilepsy must demonstrate both the emergence of spontaneous seizures after TBI and an initial latency period in a subset of TBI animals, because not all patients who incur a TBI go on to develop epilepsy. To do this, electroencephalography (EEG) with simultaneous video acquisition is used in this protocol. Understanding the technical aspects behind data acquisition hardware and approaches is critical for accurate data interpretation. The critical hardware aspects include the type of recording system, type of electrodes (screw or wire lead) and material they are made of, synchronized video acquisition (as part of the EEG system or third party), and properties of the computer system. It is imperative to set the appropriate acquisition parameters in any type of system depending on study goal, EEG events of interest, further analysis method, and sustainability of data storage. Lastly, the method of electrode configuration (montage) must be considered, as each has advantages and disadvantages and will affect the data interpretation.
This protocol details how to use the modified Marmarou weight drop model10,11 to induce diffuse injury resulting in spontaneous, unprovoked, recurrent seizures in mice, describes surgical approaches to acquire a single- and multi-channel continuous, and synchronized video EEG using monopolar, bipolar, or mixed montage.

<table><tbody><tr><td>0.10&quot; screw</td><td>Pinnacle Technology Inc., KS, USA</td><td>8209</td><td>0.10 inch long stainless steel</td></tr><tr><td>0.10&quot; screw</td><td>Pinnacle Technology Inc., KS, USA</td><td>8403</td><td>0.10 inch long with pre-soldered wire lead</td></tr><tr><td>0.12&quot; screw</td><td>Pinnacle Technology Inc., KS, USA</td><td>8212</td><td>0.12 inch long stainless steel</td></tr><tr><td>1EEG headmount</td><td>Invitro1 (subsidiary of Plastics One), VA, USA</td><td>MS333/8-A/SPC</td><td>3 individually Teflon-insulated platinum iridium wire electrodes (twisted or untwisted, 0.005 inch diameter) extending below threaded plastic pedestal</td></tr><tr><td>2EEG/1EMG headmount</td><td>Pinnacle Technology Inc., KS, USA</td><td>8201</td><td>2EEG/1EMG channels</td></tr><tr><td>3% hydrogen peroxide</td><td></td><td></td><td>Pharmacy</td></tr><tr><td>3EEG headmount</td><td>Pinnacle Technology Inc., KS, USA</td><td>8235-SM-C</td><td>custom 6-Pin Connector for 3EEG channels</td></tr><tr><td>Buprenorphine</td><td>Par Pharmaceuticals, Cos. Inc., Spring Valley, NY, USA</td><td>060969</td><td></td></tr><tr><td>Buprenorphine</td><td>Par Pharmaceuticals, Cos. Inc., Spring Valley, NY, USA</td><td>060969</td><td></td></tr><tr><td>C57BL/6 mice</td><td>Harlan/Envigo Laboratories Inc</td><td></td><td>male, 12-16 weeks old</td></tr><tr><td>C57BL/6 mice</td><td>The Jackson Laboratory</td><td></td><td>male, 12-16 weeks old</td></tr><tr><td>Carprofen</td><td>Zoetis Services LLC, Parsippany, NJ, USA</td><td>026357</td><td>NOTE: this drug is added during weight drop only if stereotactic electrode implantation will be performed on the same day</td></tr><tr><td>Chlorhexidine antiseptic</td><td></td><td></td><td>Pharmacy</td></tr><tr><td>Dental cement and solvent kit</td><td>Stoelting Co., USA</td><td>51459</td><td></td></tr><tr><td>Drill</td><td>Foredom</td><td>HP4-917</td><td></td></tr><tr><td>Drill bit</td><td>Meisinger USA, LLC, USA</td><td>HM1-005-HP</td><td>0.5 mm, Round, 1/4, Steel</td></tr><tr><td>Dry sterilizer</td><td>Cellpoint Scientific, USA</td><td></td><td>Germinator 500</td></tr><tr><td>EEG System 1</td><td>Biopac Systems, CA, USA</td><td></td><td></td></tr><tr><td>EEG System 2</td><td>Pinnacle Technology Inc., KS, USA</td><td></td><td></td></tr><tr><td>Ethanol &amp;ge;70%</td><td>VWR, USA</td><td>71001-652</td><td>KOPTEC USP, Biotechnology Grade (140 Proof)</td></tr><tr><td>Eye ointment</td><td>Pro Labs Ltd, USA</td><td></td><td>Puralube Vet Ointment Sterile Ocular Lubricant available in general online stores and pharmacies</td></tr><tr><td>Fluriso liquid for inhalation anesthesia</td><td>MWI Veterinary Supply Co., USA</td><td>502017</td><td></td></tr><tr><td>Hair removal product</td><td>Church &amp;amp; Dwight Co., Inc., USA</td><td></td><td>Nair cream</td></tr><tr><td>Isoflurane</td><td>MWI Veterinary Supply Co., USA</td><td>502017</td><td></td></tr><tr><td>Povidone-iodine surgical solution</td><td>Purdue Products, USA</td><td>004677</td><td>Betadine</td></tr><tr><td>Rimadyl/Carprofen</td><td>Zoetis Services LLC, Parsippany, NJ, USA</td><td>026357</td><td></td></tr><tr><td>Solder</td><td></td><td></td><td>Harware store</td></tr><tr><td>Soldering iron</td><td>Weller, USA</td><td>WP35</td><td>ST7 tip, 0.8mm</td></tr><tr><td>Stainless steel disc</td><td></td><td></td><td>Custom made</td></tr><tr><td>Sterile cotton swabs</td><td></td><td></td><td></td></tr><tr><td>Sterile gauze pads</td><td>Fisher Scientific, USA</td><td>22362178</td><td></td></tr><tr><td>Sterile poly-lined absorbent towels pads</td><td>Cardinal Health, USA</td><td>3520</td><td></td></tr><tr><td>Tissue adhesive</td><td>3M Animal Care Products, USA</td><td>1469SB</td><td></td></tr></tbody></table>

inducing post-traumatic epilepsy in a mouse model of repetitive diffuse traumatic brain injury

Traumatic brain injury (TBI) is a leading cause of acquired epilepsy. TBI can result in a focal or diffuse brain injury. Focal injury is a result of direct mechanical forces, sometimes penetrating through the cranium, creating a direct lesion in the brain tissue. These are visible during brain imaging as areas with contusion, laceration, and hemorrhage. Focal lesions induce neuronal death and glial scar formation and are present in 20%&minus;25% of all people who incur a TBI. However, in the majority of TBI cases, injury is caused by acceleration-deceleration forces and subsequent tissue shearing, resulting in nonfocal, diffuse damage. A subpopulation of TBI patients continues to develop post-traumatic epilepsy (PTE) after a latency period of months or years. Currently, it is impossible to predict which patients will develop PTE, and seizures in PTE patients are challenging to control, necessitating further research. Until recently, the field was limited to only two animal/rodent models with validated spontaneous post-traumatic seizures, both presenting with large focal lesions with massive tissue loss in the cortex and sometimes subcortical structures. In contrast to these approaches, it was determined that diffuse TBI induced using a modified weight drop model is sufficient to initiate development of spontaneous convulsive and non-convulsive seizures, even in the absence of focal lesions or tissue loss. Similar to human patients with acquired post-traumatic epilepsy, this model presents with a latency period after injury before seizure onset. In this protocol, the community will be provided with a new model of post-traumatic epilepsy, detailing how to induce diffuse non-lesional TBI followed by continuous long-term video-electroencephalographic animal monitoring over the course of several months. This protocol will detail animal handling, the weight drop procedure, the electrode placement for two acquisition systems, and the frequent challenges encountered during each of the steps of surgery, postoperative monitoring, and data acquisition.

The protocol outlined here describes the method for induction of a diffuse injury in isolation (e.g., in the absence a focal lesion) using a mouse model of repetitive diffuse TBI (Figure 1). Figure 1A depicts the weight drop device and its components (Figure 1A, a1&#8722;a5) used for induction of TBI in this model and crucial steps during the procedure (Figure 1...

Watch this Scientific Journal Video about Inducing Post-Traumatic Epilepsy in a Mouse Model of Repetitive Diffuse Traumatic Brain Injury at JoVE.com

Inducing Post-Traumatic Epilepsy in a Mouse Model of Repetitive Diffuse Traumatic Brain Injury

This systematic protocol describes a new animal model of post-traumatic epilepsy after repetitive mild traumatic brain injury. The first part details steps for traumatic brain injury induction using a modified weight drop model. The second part provides instructions on the surgical approach for single- and multi-channel electroencephalographic data acquisition systems.

Traumatic brain injury (TBI) is a leading cause of acquired epilepsy. TBI can result in a focal or diffuse brain injury. Focal injury is a result of ...

inducing-post-traumatic-epilepsy-mouse-model-repetitive-diffuse

Research

JoVE Journal

Behavior

10.4K Views.  Fralin Biomedical Research Institute at Virginia Tech Carilion. This systematic protocol describes a new animal model of post-traumatic epilepsy after repetitive mild traumatic brain injury. The first part details steps for traumatic brain injury induction using a modified weight drop model. The second part provides instructions on the surgical approach for single- and multi-channel electroencephalographic data acquisition systems.

Video: Inducing Post-Traumatic Epilepsy in a Mouse Model of Repetitive Diffuse Traumatic Brain Injury

Use of a Wireless Video-EEG System to Monitor Epileptiform Discharges Following Lateral Fluid-Percussion Induced Traumatic Brain Injury

The lateral fluid percussion injury (FPI) model is well established and has been used to study TBI and post-traumatic epilepsy (PTE). However, considerable variability has been reported for the specific parameters used in different studies that have employed this model, making it difficult to harmonize and interpret the results between laboratories. For example, variability has been reported regarding the size and location of the craniectomy, how the Luer lock hub is placed relative to the craniectomy, the atmospheric pressure applied to the dura and the duration of the pressure pulse. Each of these parameters can impact injury severity, which directly correlates with the incidence of PTE. This has been manifested as a wide range of mortality rates, righting reflex times and incidence of convulsive seizures reported. Here we provide a detailed protocol for the method we have used to help facilitate harmonization between studies. We used FPI in combination with a wireless EEG telemetry system to continuously monitor for electrographic changes and detect seizure activity.&#160; FPI is induced by creating a 5 mm craniectomy over the left hemisphere, between the Bregma and Lambda and adjacent to the lateral ridge. A Luer lock hub is secured onto the skull over the craniectomy. This hub is connected to the FPI device, and a 20-millisecond pressure pulse is delivered directly to the intact dura through pressure tubing connected to the hub via a twist lock connector. Following recovery, rats are re-anesthetized to remove the hub. Five 0.5 mm, stainless steel EEG electrode screws are placed in contact with the dura through the skull and serve as four recording electrodes and one reference electrode. The electrode wires are collected into a pedestal connector which is secured into place with bone cement. Continuous video/EEG recordings are collected for up to 4 weeks post TBI.

Here we present a protocol to induce severe TBI with the lateral fluid percussion injury (FPI) model in adult, male Wistar rats. We also demonstrate the use of a wireless telemetry system to collect continuous video-EEG recordings and monitor for epileptiform discharges consistent with post-traumatic epileptogenesis.&#160;

The lateral fluid percussion injury (FPI) model is well established and has been used to study TBI and post-traumatic epilepsy (PTE). However, ...

A Repetitive Concussive Head Injury Model in Mice

Despite the concussion/ mild traumatic brain injury (mTBI) being the most frequent occurrence of traumatic brain injury, there is still a lack of knowledge on the injury and its effects. To develop a better understanding of concussions, animals are often used because they provide a controlled, rigorous, and efficient model. Studies have adapted traditional animal models to perform mTBI to stimulate mild injury severity by changing the injury parameters. These models have been used because they can produce morphologically similar brain injuries to the clinical condition and provide a spectrum of injury severities. However, they are limited in their ability to present the identical features of injuries in patients. Using a traditional impact system, a repetitive concussive injury (rCHI) model can induce mild to moderate human-like concussion. The injury degree can be determined by measuring the period of loss of consciousness (LOC) with a sign of a transient termination of breathing. The rCHI model is beneficial to use for its accuracy and simplicity in determining mTBI effects and potential treatments.

Concussion presents the most common type of traumatic brain injury. Therefore, a repetitive concussive animal model, which replicates the important features of an injury in patients, may provide a means to study concussion in a rigorous, controlled, and efficient manner.

Despite the concussion/ mild traumatic brain injury (mTBI) being the most frequent occurrence of traumatic brain injury, there is still a lack of ...

Medicine

Pentylenetetrazole-Induced Kindling Mouse Model

Pentylenetetrazole (PTZ) is a GABA-A receptor antagonist. An intraperitoneal injection of PTZ into an animal induces an acute, severe seizure at a high dose, whereas sequential injections of a subconvulsive dose have been used for the development of chemical kindling, an epilepsy model. A single low-dose injection of PTZ induces a mild seizure without convulsion. However, repetitive low-dose injections of PTZ decrease the threshold to evoke a convulsive seizure. Finally, continuous low-dose administration of PTZ induces a severe tonic-clonic seizure. This method is simple and widely applicable to investigate the pathophysiology of epilepsy, which is defined as a chronic disease that involves repetitive seizures. This chemical kindling protocol causes repetitive seizures in animals. With this method, vulnerability to PTZ-mediated seizures or the degree of aggravation of epileptic seizures was estimated. These advantages have led to the use of this method for screening anti-epileptic drugs and epilepsy-related genes. In addition, this method has been used to investigate neuronal damage after epileptic seizures because the histological changes observed in the brains of epileptic patients also appear in the brains of chemical-kindled animals. Thus, this protocol is useful for conveniently producing animal models of epilepsy.

This protocol describes a method of chemical kindling with pentylenetetrazole and provides a mouse model of epilepsy. This protocol can also be used to investigate vulnerability to seizure induction and pathogenesis after epileptic seizures in mice.

Pentylenetetrazole (PTZ) is a GABA-A receptor antagonist. An intraperitoneal injection of PTZ into an animal induces an acute, severe seizure at a high ...

Neuroscience

A Mouse Model of Single and Repetitive Mild Traumatic Brain Injury

Mild Traumatic Brain Injury (mTBI) can result in the acute loss of brain function, including a period of confusion, a loss of consciousness (LOC), focal neurological deficits and even amnesia. Athletes participating in contact sports are at high risk of exposure to large number of mTBIs. In terms of the level of injury in a sporting athlete, a mTBI is defined as a mild injury that does not cause gross pathological changes, but does cause short-term neurological deficits that are spontaneously resolved. Despite previous attempts to model mTBI in mice and rats, many have reported gross adverse effects including skull fractures, intracerebral bleeding, axonal injury and neuronal cell death. Herein, we describe our highly reproducible animal model of mTBI that reproduces clinically relevant symptoms. This model uses a custom made pneumatic impactor device to deliver a closed-head trauma. This impact is made under precise velocity and deformation parameters, creating a reliable and reproducible model to examine the mechanisms that contribute to effects of single or repetitive concussive mTBI.

Athletes absorb several hundred mild traumatic brain injuries (mTBI)/concussions every year; however, the consequence of these on the brain is poorly understood. Therefore, an animal model of single and repetitive mTBI that consistently replicates clinically relevant symptoms provides the means to advance the study of mTBI and concussion.

Mild Traumatic Brain Injury (mTBI) can result in the acute loss of brain function, including a period of confusion, a loss of consciousness (LOC), focal ...

A Novel and Translational Rat Model of Concussion Combining Force and Rotation with In Vivo Cerebral Microdialysis

Persistent cognitive and motor symptoms are known consequences of concussions/mild traumatic brain injury (mTBIs) that can be partly attributable to altered neurotransmission. Indeed, cerebral microdialysis studies in rodents have demonstrated an excessive extracellular glutamate release in the hippocampus within the first 10 min following trauma. Microdialysis offers the clear advantage of in vivo neurotransmitter continuous sampling while not having to sacrifice the animal. In addition to the aforementioned technique, a closed head injury model that exerts rapid acceleration and deceleration of the head and torso is needed, as such a factor is not available in many other animal models. The Wayne State weight-drop model mimics this essential component of human craniocerebral trauma, allowing the induction of an impact on the head of an unrestrained rodent with a falling weight. Our novel and translational rat model combines cerebral microdialysis with the Wayne State weight-drop model to study, in lightly anesthetized and unrestrained adult rats, the acute changes in extracellular neurotransmitter levels following concussion. In this protocol, the microdialysis probe was inserted inside the hippocampus as region of interest, and was left inserted in the brain at impact. There is a high density of terminals and receptors in the hippocampus, making it a relevant region to document altered neurotransmission following concussion. When applied to adult Sprague-Dawley rats, our combined model induced increases in hippocampal extracellular glutamate concentrations within the first 10 min, consistent with the previously reported post-concussion symptomology. This combined weight-drop model provides a reliable tool for researchers to study early therapeutic responses to concussions in addition to repetitive brain injury, since this protocol induces a closed-head mild trauma.

Neurotransmitter alteration is a mechanism of neural dysfunction that occurs after concussion and contributes to the sometimes-catastrophic long-term consequences. This rat model combines microdialysis, allowing in vivo neurotransmitter quantification, with a weight-drop technique exerting rapid acceleration and deceleration of the head and torso, an important factor of human craniocerebral trauma.

Persistent cognitive and motor symptoms are known consequences of concussions/mild traumatic brain injury (mTBIs) that can be partly attributable to ...

rmTBI Induction in Mice via a Closed-Head Injury Method

Modified Mouse Model of Repetitive Mild Traumatic Brain Injury Incorporating Thinned-Skull Window and Fluid Percussion

Mild traumatic brain injury is a clinically highly heterogeneous neurological disorder. Highly reproducible traumatic brain injury (TBI) animal models with well-defined pathologies are urgently needed for studying the mechanisms of neuropathology after mild TBI and testing therapeutics. Replicating the entire sequelae of TBI in animal models has proven to be a challenge. Therefore, the availability of multiple animal models of TBI is necessary to account for the diverse aspects and severities seen in TBI patients. CHI is one of the most common methods for fabricating rodent models of rmTBI. However, this method is susceptible to many factors, including the impact method used, the thickness and shape of the skull bone, animal apnea, and the type of head support and immobilization utilized. The aim of this protocol is to demonstrate a combination of the thinned-skull window and fluid percussion injury (FPI) methods to produce a precise mouse model of CHI-associated rmTBI. The primary objective of this protocol is to minimize factors that could impact the accuracy and consistency of CHI and FPI modeling, including skull bone thickness, shape, and head support. By utilizing a thinned-skull window method, potential inflammation due to craniotomy and FPI is minimized, resulting in an improved mouse model that replicates the clinical features observed in patients with mild TBI. Results from behavior and histological analysis using hematoxylin and eosin (HE) staining suggest that rmTBI can lead to a cumulative injury that produces changes in both behavior and gross morphology of the brain. Overall, the modified CHI-associated rmTBI presents a useful tool for researchers to explore the underlying mechanisms that contribute to focal and diffuse pathophysiological changes in rmTBI.

Author Spotlight: Optimizing Rodent Models for Investigating the Mechanisms and Rehabilitation in Repeated Mild Traumatic Brain Injury

This protocol presents a modified mouse model of repetitive mild traumatic brain injury (rmTBI) induced via a closed-head injury (CHI) method. The approach features a thinned-skull window and fluid percussion to reduce the inflammation commonly caused by meninges exposure, along with improved reproducibility and accuracy in modeling rmTBI in rodents.

Mild traumatic brain injury is a clinically highly heterogeneous neurological disorder. Highly reproducible traumatic brain injury (TBI) animal models ...

Establishing a Pentylenetetrazole-Induced Epileptic Seizure Model in Mice

Source: Shimada, T., et al. <a href="https://app.jove.com/v/56573">Pentylenetetrazole-Induced Kindling Mouse Model.</a> J. Vis. Exp. (2018).
This video demonstrates the process of inducing epilepsy in mice using pentylenetetrazole (PTZ) injections, a GABA-A receptor antagonist. Repeated intraperitoneal administration of PTZ progressively lowers the seizure threshold by inhibiting chloride ion influx, disrupting inhibitory neurotransmission, and leading to hyperexcitability in neurons that trigger seizures. This process results in kindling and the development of spontaneous seizures, mimicking chronic epilepsy.

Source: Shimada, T., et al. Pentylenetetrazole-Induced Kindling Mouse Model. J. Vis. Exp. (2018).
This video demonstrates the process of inducing epilepsy ...

JoVE Encyclopedia of Experiments

Neuropathology

Epilepsy and Seizure Disorders

Technique to Induce Post-Traumatic Seizures in a Mouse Model via a Weight Drop Traumatic Injury

Source: Shandra, O. et al., <a href="https://app.jove.com/v/60360">Inducing Post-Traumatic Epilepsy in a Mouse Model of Repetitive Diffuse Traumatic Brain Injury.</a> J. Vis. Exp. (2020)

Source: Shandra, O. et al., Inducing Post-Traumatic Epilepsy in a Mouse Model of Repetitive Diffuse Traumatic Brain Injury. J. Vis. Exp. ...

Trauma

Generating a Mouse Model of Traumatic Brain Injury Using an Impactor Device

Source: Schwulst, S. J. et al. <a href="https://app.jove.com/v/60027">Murine Model of Controlled Cortical Impact for the Induction of Traumatic Brain Injury.</a> J. Vis. Exp. (2019)
This video demonstrates the procedure for inducing traumatic brain injury (TBI) in a mouse model. An anesthetized mouse with an exposed skull is taken to create an opening in the skull, and then a controlled cortical injury is induced using an impact device. The injury damages the brain tissue, causing impaired cognitive function and motor coordination.

All procedures involving animal models have been reviewed by the local institutional animal care committee and the JoVE veterinary review board.
1. Induce ...

Modeling Repetitive Concussive Head Injuries in a Mouse Model

<a href='https://app.jove.com/v/54530/a-repetitive-concussive-head-injury-model-in-mice'>Source: Yang, Z., et.al.&#160;A Repetitive Concussive Head Injury Model in Mice. J. Vis. Exp. (2016).</a>This video demonstrates the induction of repetitive concussive head injuries in a mouse using an electromagnetic impact device. The procedure involves positioning the impact tip between the interfrontal and lambdoid sutures on the skull of an anesthetized mouse and using a probe tip to precisely set the impact depth. The impact is delivered at a controlled velocity and depth to simulate mild traumatic brain injuries, followed by a recovery period, with the injuries repeated at specified intervals.

Source: Yang, Z., et.al.&#160;A Repetitive Concussive Head Injury Model in Mice. J. Vis. Exp. (2016).This video demonstrates the induction of repetitive ...