Name: a novel model of mild traumatic brain injury for juvenile rats
Uploaded: 2014-12-08T13:00:00.000+00:00
Duration: 7 min 36 s
Description: Watch this Scientific Journal Video about A Novel Model of Mild Traumatic Brain Injury for Juvenile Rats at JoVE.com

The authors would like to thank Irene Ma, Rose Tobais, and Jong Rho for their technical assistance. Funding was provided to MJE by the Department of Pediatrics at the University of Calgary, the Alberta Children&#8217;s Hospital Foundation (ACHF) and the Alberta Children&#8217;s Hospital Research Institute (ACHRI). The Postdoctoral fellowship for RM was provided by ACHF.

NOTA: Tutti gli esperimenti sono stati eseguiti in conformità con il Consiglio canadese della cura degli animali e sono stati approvati dalla University of Calgary, per animali Comitato Etico. 1. Allevamento e preparazione degli animali <ol><li> Ordinare ratte gravide di fornitori di animali da laboratorio standard o cuccioli di razza in casa secondo protocolli di allevamento standard. </li><li> Casa tutti gli animali con ad libitum accesso a cibo e acqua, in un topo stanza contenitore a temperatura controllata (21 ° C), che è mantenuto su una luce 12:12 hr: ciclo scuro. </li><li> Quando cuccioli raggiungono postnatale giorno 21 (P21), svezzare i cuccioli dalle loro madri e casa in gruppi dello stesso sesso di 3 o 4. </li></ol> 2. Set-up di Mild Traumatic Brain Injury (mTBI) Apparecchi <ol><li> Prima dell&#39;inizio della procedura, pesi mulino alla massa desiderato (ad esempio 150 g). Saldamente allegare un anello di metallo all&#39;estremità superiore del peso consente al filo da pesca di essere fisso al peso. </li><li> Punteggio stagnola con una lametta affilata. Assicurarsi che la carta stagnola segnato sostiene il peso corporeo del ratto ma non interferirà con l&#39;accelerazione del ratto seguente impatto della testa con il peso. </li><li> Nastro il stagnola ottenuto alla fase U in plastica trasparente (38 x 27 x 27 cm 3) che contiene una spugna di raccolta (38 x 25 x 15 cm 3) (Figura 1), in modo che sia teso. </li><li> Posizionare la fase di plastica a forma di U nella posizione corretta sotto il tubo di guida in plastica trasparente. </li><li> Tenere il tubo di guida di plastica (2,2 cm di diametro x 1,5 m) in posizione con uno stand morsetto e posizionare il tubo di guida in modo che è di 3,5 cm sopra la stagnola segnato. </li><li> Fissare la lenza attraverso l&#39;anello metallico al peso garantire che il fondo del peso pende liberamente 2,5 centimetri sopra la stagnola segnato. </li><li> Collegare saldamente la linea di pesca al supporto pinza. NOTA: Tethering il peso per la vongolabasamento p ad una altezza di 2,5 cm sopra la stagnola impedisce re-colpi mentre il ratto sta cadendo dall&#39;impatto alla spugna di raccolta). </li><li> Tirare il peso attraverso il tubo di guida di plastica con la lenza e tenerlo in posizione con un perno chiave esagonale a 1,0 m. </li></ol> 3. induzione di mTBI <ol><li> Quando i ratti raggiungono P30 spostamento gabbie nella stanza procedurale. </li><li> Inserire ratti in una camera isoflurano e leggermente anestetizzare il ratto finché non è sensibile ad una zampa o la coda pinch. </li><li> Introdurre rapidamente il ratto petto in giù sul stagnola segnato con la testa direttamente nel percorso del peso cadente. Vedere la Figura 2. Se il topo comincia a muoversi o wake-up prima di poter essere immesso sul stagnola segnato, tornare alla camera di isoflurano fino che non risponde a una zampa o la coda pizzico e ricominciare. </li><li> Estrarre il perno chiave a brugola, permettendo il peso cadere verticalmente attraverso il tubo di guida plastica e colpire il topo sulla testa. The ratto rapidamente subire una rotazione di 180 ° e la terra in posizione supina. </li><li> Rimuovere immediatamente il ratto dalla spugna di raccolta e applicare lidocaina topica alla testa del ratto con un applicatore con punta di cotone. </li><li> Posizionare il ratto in posizione supina in una gabbia pulita che viene riscaldata impostando su di una piastra elettrica disponibile in commercio. </li><li> Utilizzando un cronometro o timer digitale acquisire il &quot;time-to-destra&quot;. Time-to-destra è il tempo impiegato per il ratto di svegliarsi dall&#39;anestesia e capovolgere dalla posizione supina alla posizione prona o iniziare a camminare. </li><li> Ritorna il ratto della sua casa-gabbia dopo aver recuperato un comportamento normale (grooming, camminare, esplorare, etc.). </li><li> Ripetere i passaggi 3,2-3,8 per ogni ratto supplementare che richiede un mTBI. </li><li> Ripetere la procedura sulla stessa ratto a diversi intervalli di tempo per gli esperimenti mTBI ripetitive. </li></ol> 4. Induzione della Sham Injury <ol><li> Leggermente Anesthetize il ratto con isoflurano fino a quando è non risponde ad una zampa o la coda pizzico. </li><li> Introdurre rapidamente il ratto petto in giù sul stagnola segnato con la testa direttamente nel percorso del peso cadente. </li><li> Rimuovere il ratto dal stagnola senza tirare il perno brugola dal tubo di guida in plastica e applicare lidocaina topica alla testa del ratto con un applicatore con punta di cotone. </li><li> Posizionare il ratto in posizione supina in una gabbia pulita che viene riscaldata impostando su di una piastra elettrica disponibile in commercio. </li><li> Utilizzare un cronometro o timer digitale per acquisire il &quot;time-to-destra&quot;. </li><li> Ritorna il ratto della sua casa-gabbia dopo aver recuperato un comportamento normale (grooming, camminare, esplorare, etc.). </li></ol> 5. Verifica dei mTBI con il Walking Beam Test 8 <ol><li> 24 ore dopo l&#39;induzione del mTBI o animali sham ritorno pregiudizio alla camera procedurale. </li><li> Trasferire i ratti in una gabbia tenuta pulitae posizionare home-gabbia del ratto a fine stretta dei 165 centimetri rastremate raggio in modo che la porzione aperta della casa gabbia affacciantesi all&#39;estremità più stretta del fascio. NOTA: Il fascio conico è lunga 165 centimetri. La piattaforma centro del fascio ha una larghezza di 6 cm in estremità larga e 1,75 cm in estremità stretta. Il fascio di centro ha sporgenze (2 cm di larghezza e 2 cm sotto la trave centrale) che forniscono la sicurezza quando scivola il piede del ratto. Posizionare imbottitura in schiuma sotto il fascio per ridurre il rischio di lesioni ai ratti che potrebbe cadere il fascio durante la prova. </li><li> Inserire una videocamera alla estremità larga del fascio e la posizione rastremato / immagine videocamera per assicurare che il ricercatore guardando il video può chiaramente vedere i movimenti di ratto per l&#39;intera lunghezza della trave rastremata. </li><li> Posizionare il topo alla larga del fascio conico e incoraggiarla a attraversare il raggio della sua casa-gabbia. Una volta che il topo attraversa il fascio conico, lasciare il ratto nella sua casa-gabbia per almeno 60 sec a reinForce il percorso di destinazione. Questo è Trial # 1 e non inclusi nell&#39;analisi. </li><li> Accendere la videocamera e permette al topo per completare l&#39;operazione fascio-walking 4 volte supplementari (mantenendo i periodi di rinforzo 60 sec nella gabbia di casa). Una volta che il topo ha completato tutte le prove, ritorno il ratto alla sua casa-gabbia. </li><li> A segnare, registrare il numero di posteriori della gamba piede-scivola che si verificano e il tempo / tempo di attraversare il fascio, per ogni singola prova. Utilizzare questi dati per calcolare il numero medio di gambe posteriori piede scivola e tempo di attraversare il fascio per ciascun ratto. </li></ol>

<ol>
	<li>DeWitt, D., Perez-Polo, R., Hulsebosch, C., Dash, P., Robertson, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Challenges+in+the+development+of+rodent+models+of+mild+traumatic+brain+injury.">Challenges in the development of rodent models of mild traumatic brain injury.</a> Journal of Neurotrauma. 30, 688-701 (2013).</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 Reviews Neuroscience. 14, 128-142 (2013).</li><li>Zhang, Z., Lerner, S., Kobiessy, F., Hayes, R., Wang, K., Yan, Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Systems+biology+and+the+anostic+approach+to+drug+discovery+and+development+to+treat+traumatic+brain+injury.">Systems biology and the anostic approach to drug discovery and development to treat traumatic brain injury.</a> Systems Biology in Drug Discovery and Development: Methods and Protocols, Methods in Molecular Biology. , .</li><li>Viano, D., Casson, I., Pellmen, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Concussion+in+profession+football:+Biomechanics+of+the+struck+player+-+Part+14.">Concussion in profession football: Biomechanics of the struck player - Part 14.</a> Neurosurgery. 61, 313-327 (2007).</li><li>Marmarou, 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=A+new+model+of+diffuse+brain+injury+in+rats:+Part+1+-+Pathophysiology+and+biomechanics.">A new model of diffuse brain injury in rats: Part 1 - Pathophysiology and biomechanics.</a> Journal of Neurosurgery. 80, 291-300 (1994).</li><li>Mychasiuk, R., Farran, A., Esser, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessment+of+an+experimental+rodent+model+of+pediatric+mild+traumatic+brain+injury.">Assessment of an experimental rodent model of pediatric mild traumatic brain injury.</a> Journal of Neurotrauma. 31 (8), (2014).</li><li>Kane, 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=A+mouse+model+of+human+repetitive+mild+traumatic+brain+injury.">A mouse model of human repetitive mild traumatic brain injury.</a> Journal of Neuroscience Methods. 203, 41-49 (2012).</li><li>Schallert, T., Woodlee, M., Fleming, S., Krieglstein, J., Klumpp, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Disentangling+multiple+types+of+recovery+from+brain+injury.">Disentangling multiple types of recovery from brain injury.</a> Pharmacology of Cerebral Ischemia. , (2002).</li><li>Mychasiuk, R., Hehar, H., Farran, A., Esser, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mean+Girls:+Sex+differences+in+the+effects+of+mild+traumatic+brain+injury+on+the+social+dynamics+of+juvenile+rat+play+behaviour.">Mean Girls: Sex differences in the effects of mild traumatic brain injury on the social dynamics of juvenile rat play behaviour.</a> Behavioural Brain Research. 259, (2014).</li><li>Centers for Disease Control and Prevention. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Report to congress on mild traumatic brain injury in the United States: Steps to prevent a serious public health problem. , 1-47 (2003).</li></ol>

No competing financial interests exist.

Reliable modelling systems are needed to effectively cultivate basic science research that has significant translational validity. In response to rising occurrences and popular media, the investigation of mTBI and concussion has become a priority in many disciplines. However, despite increased research, there have been only incremental improvements in therapeutic strategies and treatment options 3. This lack of progress may be partially due to a discrepancy between the modeling systems employed and actual injury etiology. The majority of studies utilized rodent models that failed to reproduce the important biomechanical forces and appropriate post-injury symptomology. The current human definition of mTBI specifies that the injury results from acceleration and deceleration forces associated with a blunt trauma 10. The modified weight drop technique described here is therefore an ideal model for the study of mTBI and concussion because it uses a glancing impact to cause rapid rotational acceleration and deceleration to the head of an unrestrained animal, mimicking the biomechanical forces identified in sports-related injuries and automobile accidents. In addition, this model is easily adapted to examine repetitive mTBI, a phenomena that is emerging as a serious medical and socioeconomic issue. Studies indicate that rodents may be exposed to a series of 10 distinct mTBIs with minimal mortality 7. Finally, the method is inexpensive and can be carried out rapidly, allowing for high-throughput examination of a many therapeutic compounds and treatment regiments. 
Just as with any procedural technique, certain aspects of the protocol are particularly important to the generation of reliable results. First, the tin foil needs to be scored effectively. If the tin foil is not properly scored, the force imparted by the weight during the glancing impact will not be enough to propel the juvenile rat through the tin foil onto the collection sponge. In these situations, the rat will remain in the starting position (chest down on the tin foil) and the mTBI will result from the blunt trauma from the weight impacting the stationary head, not the rotational acceleration and deceleration desired. Second, during the induction of the mTBI and the sham injury, the level of anesthetic applied to each rat should be consistent. Owing to the fact that time-to-right is used as marker of mTBI, the researcher should try to ensure that animals receiving a mTBI and animals receiving a sham injury are exposed to similar levels of anesthetic. A major advantage to this technique over many other TBI procedures is the low level and duration of anesthesiology. However, the juvenile rat needs to be non-responsive to a toe or tail pinch to ensure they do not wake-up on the stage before the injury is induced. Finally, in order to maintain a consistent injury etiology, the positioning of the rat&#8217;s head is particularly important. Ideally the weight should impact the center of the dorsal surface of the head. Caution should be taken to avoid positioning the path of the weight too near the caudal/posterior portion of the head, as impacting the brainstem and cerebellum is associated with increased mortality and seizure activity. 
Based upon the biomechanical pathophysiology of injury induction and the behavioural outcomes examined, the modified weight-drop technique appears to be a reliable model for the investigation of paediatric mTBI and concussion. Although preliminary studies of this novel model have assessed some basic molecular and structural changes 7 future studies will be needed to ascertain how the brain responds to a mTBI with this injury etiology. An in-depth analysis of the neuroanatomical and biological changes that occur at the cellular and epigenetic level would increase model validity and translational applicability. In addition to stimulating the generation of targeted pharmacological therapies, understanding the pathophysiological changes that occur in the brain in response to mTBI and concussion would also direct the research related to clinical biomarkers that have the ability to predict outcomes following injury.

Anche se ci sono molti metodi ampiamente utilizzati per la generazione di moderata-grave trauma cranico (TBI), sono state sviluppate poche tecniche per indurre lievi, chiuso ferite alla testa nei roditori. A causa del fatto che il trauma cranico lieve (mTBI) è tre volte più comune di lesione cerebrale moderata e grave combinata 1, è necessario un modello affidabile di mTBI per facilitare la ricerca in materia di fisiopatologia, risultati neurobiologici e comportamentali, e strategie terapeutiche. Ad esempio, gli studi clinici di droga in parte a causa dei limiti di modelli animali attuali 2, negli ultimi dieci anni ci sono stati più di 200 non riusciti per il trattamento di TBI 3. Quando i sistemi di modellazione sono generati per studi di ricerca traslazionale, l&#39;applicabilità dei risultati dipendono dalla validità del modello implementato. Per lo studio della mTBI / sbattimento, un modello animale affidabile non solo imitare il forze biomeccanico responbile per lesioni eziologia, ma potrebbe anche indurre sintomi compatibili con quelli riportati dalla popolazione clinicamente rilevante. Inoltre, perché i bambini sono a rischio particolarmente elevato per mTBI, sistemi di modellazione ottimale sarebbe applicabile ai roditori giovani e giovanili, oltre ai loro equivalenti adulti. Analisi biomeccaniche di circostanze in cui gli atleti hanno sostenuto mTBIs o lesioni cerebrali concussive indicano che i fattori predittivi più critici per infortunio sono accelerazioni testa rapidi e impatti ad alta velocità 4. La maggior parte dei modelli di roditori attualmente utilizzati per l&#39;induzione di TBI permette poco o nessun movimento della testa 5 (per una rassegna vedi 2). Il modello qui delineato, fornisce un impatto ad alta velocità alla testa di un ratto giovanile fisicamente incontrollato che è accompagnata da una rotazione di 180 ° e caduta libera che applica forze di accelerazione / decelerazione di testa e corpo del soggetto. Tqui sono due vantaggi principali di questa tecnica di peso goccia modificato per l&#39;induzione di mTBI. In primo luogo, il modello produce concussive clinicamente rilevante come sintomatologia senza causare alcun danno evidente al cervello (per la descrizione completa dei risultati comportamentali vedi 6). Coerente anche con i rapporti clinici di sindrome post-concussive, questa tecnica di peso-drop modificato produce risultati eterogenei. Anche se gli effetti della mTBI sono significativi, vi è una sostanziale differenza tra i roditori che hanno subito un mTBI se esaminato su più misure di outcome. In secondo luogo, il metodo consente lo studio di mTBI ripetitivo 7. Poiché la maggior parte dei modelli TBI esistenti infliggere tali lesioni gravi, è spesso difficile indurre una seconda ferita, e quasi impossibile studiare TBI ripetitivo senza danni estesi a tutta la corteccia. Pertanto, la logica principale per utilizzare la tecnica del peso goccia modificato per l&#39;induction di mTBI è quello di produrre una ferita che rappresenta più da vicino la fisiopatologia e la sintomatologia di concussione e ripetitivo TBI nelle popolazioni giovanili. Con la crescente incidenza di mTBI legati allo sport, cadute, e incidenti automobilistici, soprattutto durante l&#39;infanzia, questo modello roditore unico di mTBI fornisce ai ricercatori uno strumento prezioso per lo studio delle lesioni cerebrali concussive-like che può essere facilmente applicato a multiple-hit paradigmi.

<table><tbody><tr><td>Brass Weights</td><td>Ginsberg Scientific</td><td>7-2500-2</td><td>Need to have metal loop attached to base</td></tr><tr><td>Alluminum Foil</td><td>Alcan</td><td></td><td>Available at most grocery stores</td></tr><tr><td>Masking Tape</td><td></td><td></td><td>Commercially available&amp;nbsp;</td></tr><tr><td>U-Shaped Plastic Stand</td><td></td><td></td><td>Constructed by Laboratory</td></tr><tr><td>Clamp Stand</td><td>Sigma-Aldrich</td><td>Z190357</td><td></td></tr><tr><td>Plastic Guide Tube</td><td></td><td></td><td>Could be constructed or purchased at a hardware store</td></tr><tr><td>Fishing Line</td><td>Angler 10lb&amp;nbsp;</td><td></td><td>Purchased from a sporting goods retailer&amp;nbsp;</td></tr><tr><td>Isoflurane</td><td>Pharmaceutical Partners of Canada</td><td>DIN 02237518</td><td>Inhalation Anesthetic</td></tr><tr><td>Topical Lidocaine (30ml)</td><td>Astra Zeneca</td><td>DIN 0001694</td><td>Xylocaine Jelly 2%&amp;nbsp;</td></tr><tr><td>Cotton Swabs</td><td></td><td></td><td>Commercially available&amp;nbsp;</td></tr><tr><td>Heating Pad - 3 heat setting</td><td></td><td></td><td>Commercially available&amp;nbsp;</td></tr><tr><td>Stop Watch</td><td>Sportline</td><td>L303</td><td>Purchased from a sporting goods retailer&amp;nbsp;</td></tr><tr><td>Video Camera</td><td>Sony</td><td>HDR-CX260V</td><td></td></tr><tr><td>Sprague Dawley Rats</td><td>Charles River Laboratories</td><td>SAS SD 40</td><td>Male and females ordered from Charles River Laboratories and pups bred in-house</td></tr><tr><td>Balance Beam</td><td></td><td></td><td>Constructed by Laboratory</td></tr></tbody></table>

a novel model of mild traumatic brain injury for juvenile rats

Despite growing evidence that childhood represents a major risk period for mild traumatic brain injury (mTBI) from sports-related concussions, motor vehicle accidents, and falls, a reliable animal model of mTBI had previously not been developed for this important aspect of development. The modified weight-drop technique employs a glancing impact to the head of a freely moving rodent transmitting acceleration, deceleration, and rotational forces upon the brain. When applied to juvenile rats, this modified weight-drop technique induced clinically relevant behavioural outcomes that were representative of post-concussion symptomology. The technique is a rapidly applied procedure with an extremely low mortality rate, rendering it ideal for high-throughput studies of therapeutics. In addition, because the procedure involves a mild injury to a closed head, it can easily be used for studies of repetitive brain injury. Owing to the simplistic nature of this technique, and the clinically relevant biomechanics of the injury pathophysiology, the modified weight-drop technique provides researchers with a reliable model of mTBI that can be used in a wide variety of behavioural, molecular, and genetic studies.

La tecnica di peso-drop modificato sopra descritto è un metodo affidabile per l&#39;induzione di lieve trauma cranico (mTBI) in ratti giovani. Utilizzando un peso di 150 g impatto, questa tecnica è stata applicata con successo per ratti giovani che vanno 50-120 g. Inoltre, la procedura può essere facilmente ripetuta negli stessi animali per lo studio di mTBI ripetitivo. Anche se gli animali che l&#39;esperienza di una singola esposizione mTBI un aumento del time-to-destra (figura 3) e sembrano storditi al risveglio, hanno rapidamente riprendere le attività normali e sono visivamente indistinguibili da animali sham-feriti. Dato che la lesione è lieve, lidocaina topica che elimina qualsiasi dolore associato con l&#39;impatto un&#39;occhiata, è l&#39;unico analgesico desiderato. Questo è importante per la ricerca come analgesici sono noti per interferire con i processi tipici infiammatori e di recupero. A causa della mancanza di sintomatologia conclamata, il compito trave mobile è un affidabileolo che può essere utilizzato per convalidare l&#39;induzione della mTBI. E &#39;importante notare che non tutti gli animali che l&#39;esperienza di un mTBI esporranno deficit sul compito fascio piedi, ma come gruppo, ratti giovani con mTBI dimostrano molto più posteriori della gamba piede-scivola rispetto ai ratti giovani con un infortunio alla farsa (Figura 4). Un&#39;altra caratteristica fondamentale di questa tecnica peso goccia modificata è la mancanza di ritenuta applicata al ratti giovani durante l&#39;induzione lesioni. Fornendo un colpo di striscio alla testa, seguito da una rapida accelerazione rotazionale e decelerazioni, questo modello rappresenta più da vicino le forze biomeccaniche attribuite a mTBI e commozione cerebrale. Quando questa procedura viene applicata a ratti giovani o topi adulti, i tassi di mortalità sono estremamente bassi (7/202 animali giovani ~ tasso di mortalità 3,4%), e la frattura del cranio e l&#39;emorragia intracranica sono eccezionalmente rare 6,7. Inoltre, il modello produce SY clinicamente rilevantimptomology. Roditori Minorenni che hanno subito un solo mTBI dimostrato deficit nei bilanci e motori comportamenti, insieme con deficit nella funzione esecutiva, un aumento dei comportamenti depressivi-like, e alterate interazioni sociali 6,9. Allo stesso modo, topi adulti mostrano anche equilibrio e coordinazione deficit lievi che recuperano con il tempo 7. Infine, induzione di mTBI utilizzando questo modello richiede anestetico minimo e non comporta la preparazione chirurgica o scavare nel cranio. I risultati non sono quindi influenzati da effetti infiammatori o immunologici confondenti innescati dalla chirurgia o anestesia. Inoltre, il tempo di recupero rapida e mancanza di ferite aperte permette l&#39;inizio di paradigmi di test aggiuntivi per attivarsi poco dopo roditori sperimentano l&#39;mTBI. <img alt="Figura 1" fo:content-width="5in" src="/files/ftp_upload/51820/51820fig1highres.jpg" width="500" /> Figura 1: </strong<html> &gt; C rappresentazione artoon della U fase plastica e raccolta spugna con tutte le dimensioni pertinenti. Una distanza di 10 cm deve essere mantenuta tra la spugna raccolta e all&#39;inizio della fase plastica per assicurare la ratti giovani ha abbastanza tempo per completare la 180 Rotazione °. <img alt="Figura 2" fo:content-width="5in" src="/files/ftp_upload/51820/51820fig2highres.jpg" width="500" /> Figura 2: (A) rappresentazione fotografica della piattaforma di induzione pregiudizio. Il ratto viene posto giovanile petto in giù sul stagnola segnato modo che la testa è direttamente sotto il peso cadente. (B) Vista laterale della piattaforma di induzione pregiudizio. (C) dimostrazione fotografica del peso utilizzato nell&#39;induzione della mTBI . caricare / 51820 51820fig3highres.jpg &quot;width =&quot; / 500 &quot;/&gt; Figura 3: Rappresentazione grafica delle differenze medie di time-to-destra tra ratti giovani che hanno sperimentato un singolo mTBI e ratti giovani che hanno subito un infortunio alla farsa (* p &lt;0,01) ratti che hanno ricevuto una mostra mTBI un significativo aumento del. durata del tempo necessario per alzarsi dalla posizione supina. <img alt="Figura 4" fo:content-width="5in" src="/files/ftp_upload/51820/51820fig4highres.jpg" width="500" /> Figura 4: Rappresentazione grafica del numero medio di posteriori della gamba piede-scivola esposti sul compito Bilanciere da ratti giovani che ha sperimentato un singolo mTBI e ratti giovani che hanno subito un infortunio alla farsa (* p &lt;0.05).

Watch this Scientific Journal Video about A Novel Model of Mild Traumatic Brain Injury for Juvenile Rats at JoVE.com

A Novel Model of Mild Traumatic Brain Injury for Juvenile Rats

The modified weight-drop technique is an easy, cost-effective procedure used for the induction of mild traumatic brain injury in juvenile rats. This novel technique produces clinically relevant symptomology that will advance the study of mild traumatic brain injury (mTBI) and concussion.

Un modello Novel di Mild Traumatic Brain Injury per ratti giovani

Despite growing evidence that childhood represents a major risk period for mild traumatic brain injury (mTBI) from sports-related concussions, motor ...

a-novel-model-of-mild-traumatic-brain-injury-for-juvenile-rats

Research

JoVE Journal

Medicine

23.5K Views.  University of Calgary. The modified weight-drop technique is an easy, cost-effective procedure used for the induction of mild traumatic brain injury in juvenile rats. This novel technique produces clinically relevant symptomology that will advance the study of mild traumatic brain injury (mTBI) and concussion. 

Video: A Novel Model of Mild Traumatic Brain Injury for Juvenile Rats

Detecting Behavioral Deficits in Rats After Traumatic Brain Injury

With the increasing incidence of traumatic brain injury (TBI) in both civilian and military populations, TBI is now considered a chronic disease; however, few studies have investigated the long-term effects of injury in rodent models of TBI. Shown here are behavioral measures that are well-established in TBI research for times early after injury, such as two weeks, until two months. Some of these methods have previously been used at later times after injury, up to one year, but by very few laboratories. The methods demonstrated here are a short neurological assessment to test reflexes, a Beam-Balance to test balance, a Beam-Walk to test balance and motor coordination, and a working memory version of the Morris water maze that can be sensitive to deficits in reference memory. Male rats were handled and pre-trained to neurological, balance, and motor coordination tests prior to receiving parasagittal fluid percussion injury (FPI) or sham injury. Rats can be tested on the short neurological assessment (neuroscore), the beam-balance, and the Beam-Walk multiple times, while testing on the water maze can only be done once. This difference is because rats can remember the task, thus confounding the results if repeated testing is attempted in the same animal. When testing from one to three days after injury, significant differences are detected in all three non-cognitive tasks. However, differences in the Beam-Walk task were not detectable at later time points (after 3 months). Deficits were detected at 3 months in the Beam-Balance and at 6 months in the neuroscore. Deficits in working memory were detected out to 12 months after injury, and a deficit in a reference memory first appeared at 12 months. Thus, standard behavioral tests can be useful measures of persistent behavioral deficits after FPI.

The goal of the behavioral tests presented here is to detect functional deficits in rats after traumatic brain injury. Four specific tests are presented that detect deficits in behaviors to reflect the damage to specific brain areas at times extending to one year after injury.

Rilevare i deficit comportamentistici in ratti dopo la ferita di cervello traumatica

With the increasing incidence of traumatic brain injury (TBI) in both civilian and military populations, TBI is now considered a chronic disease; however, ...

Ricerca

Comportamento

Assessing Dominant-Submissive Behavior in Adult Rats Following Traumatic Brain Injury

Competition over resources such as food, territory, and mates significantly influences relationships within animal species and is mediated through social hierarchies that are often based on dominant-submissive relationships. The dominant-submissive relationship is a normal behavioral pattern among the individuals of a species. Traumatic brain injury is a frequent cause of social interaction impairment and the reorganization of dominant-submissive relationships in animal pairs. This protocol describes submissive behavior in adult male Sprague-Dawley rats after the induction of traumatic brain injury using a fluid-percussion model compared to naive rats through a series of dominant-submissive tests performed between 29 days and 33 days after induction. The dominant-submissive behavior test shows how brain injury can induce submissive behavior in animals competing for food. After traumatic brain injury, the rodents were more submissive, as indicated by them spending less time at the feeder and being less likely to arrive first at the trough compared to the control animals. According to this protocol, submissive behavior develops after traumatic brain injury in adult male rats.

The present protocol describes a rat model of fluid percussion-induced traumatic brain injury followed by a series of behavioral tests to understand the development of dominant and submissive behavior. Using this model of traumatic brain injury in conjunction with specific behavioral tests enables the study of social impairments following brain injury.

Valutazione del comportamento dominante-sottomesso nei ratti adulti a seguito di trauma cranico

Competition over resources such as food, territory, and mates significantly influences relationships within animal species and is mediated through social ...

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.

Un modello di mouse del singolo e ripetitivo dolore cerebrale traumatico lieve

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 ...

Medicina

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.

Un nuovo e traslazionale modello di commozione cerebrale che combina forza e rotazione con la microdialisi cerebrale in vivo

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

Neuroscienze

Advanced Diffusion Imaging in The Hippocampus of Rats with Mild Traumatic Brain Injury

Mild traumatic brain injury (mTBI) is the most common type of acquired brain injury. Since patients with traumatic brain injury show a tremendous variability and heterogeneity (age, gender, type of trauma, other possible pathologies, etc.), animal models play a key role in unraveling factors that are limitations in clinical research. They provide a standardized and controlled setting to investigate the biological mechanisms of injury and repair following TBI. However, not all animal models mimic the diffuse and subtle nature of mTBI effectively. For example, the commonly used controlled cortical impact (CCI) and lateral fluid percussion injury (LFPI) models make use of a craniotomy to expose the brain and induce widespread focal trauma, which are not commonly seen in mTBI. Therefore, these experimental models are not valid to mimic mTBI. Thus, an appropriate model should be used to investigate mTBI. The Marmarou weight drop model for rats induces similar microstructural alterations and cognitive impairments as seen in patients who sustain mild trauma; therefore, this model was selected for this protocol. Conventional computed tomography and magnetic resonance imaging (MRI) scans commonly show no damage following a mild injury, because mTBI induces often only subtle and diffuse injuries. With diffusion weighted MRI, it is possible to investigate microstructural properties of brain tissue, which can provide more insight into the microscopic alterations following mild trauma. Therefore, the goal of this study is to obtain quantitative information of a selected region-of-interest (i.e., hippocampus) to follow up disease progression after obtaining a mild and diffuse brain injury.

The overall goal of this procedure is to obtain quantitative microstructural information of the hippocampus in a rat with mild traumatic brain injury. This is done using an advanced diffusion-weighted magnetic resonance imaging protocol and region-of-interest based analysis of parametric diffusion maps.

Advanced Diffusion Imaging nell'ippocampo di ratti con lievi lesioni cerebrali traumatiche

Mild traumatic brain injury (mTBI) is the most common type of acquired brain injury. Since patients with traumatic brain injury show a tremendous ...

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.

Modello elettromagnetico controllato a testa chiusa di lieve lesione cerebrale traumatica nei topi

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

Assessing Changes in Synaptic Plasticity Using an Awake Closed-Head Injury Model of Mild Traumatic Brain Injury

Mild traumatic brain injuries (mTBIs) are a prevalent health issue in North America. There is increasing pressure to utilize ecologically valid models of closed-head mTBI in the preclinical setting to increase translatability to the clinical population. The awake closed-headed injury (ACHI) model uses a modified controlled cortical impactor to deliver closed-headed injury, inducing clinically relevant behavioral deficits without the need for a craniotomy or the use of an anesthetic.
This technique does not normally induce fatalities, skull fractures, or brain bleeds, and is more consistent with being a mild injury. Indeed, the mild nature of the ACHI procedure makes it ideal for studies investigating repetitive mTBI (r-mTBI). Growing evidence indicates that r-mTBI can result in a cumulative injury that produces behavioral symptoms, neuropathological changes, and neurodegeneration. r-mTBI is common in youths playing sports, and these injuries occur during a period of robust synaptic reorganization and myelination, making the younger population particularly vulnerable to the long-term influences of r-mTBI.
Further, r-mTBI occurs in cases of intimate partner violence, a condition for which there are few objective screening measures. In these experiments, synaptic function was assessed in the hippocampus in juvenile rats that had experienced r-mTBI using the ACHI model. Following the injuries, a tissue slicer was utilized to make hippocampal slices to evaluate bidirectional synaptic plasticity in the hippocampus at either 1 or 7 days following the r-mTBI. Overall, the ACHI model provides researchers with an ecologically valid model to study changes in synaptic plasticity following mTBI and r-mTBI.

Here, it is demonstrated how an awake closed-head injury model can be used for examining the effects of repeated mild traumatic brain injury (r-mTBI) on synaptic plasticity in the hippocampus. The model replicates important features of r-mTBI in patients and is used in conjunction with in vitro electrophysiology.

Valutazione dei cambiamenti nella plasticità sinaptica utilizzando un modello di trauma cranico chiuso sveglio di lieve lesione cerebrale traumatica

Mild traumatic brain injuries (mTBIs) are a prevalent health issue in North America. There is increasing pressure to utilize ecologically valid models of ...

Convalida della risposta alle lesioni e delle valutazioni comportamentali in un modello di ratto mTBI

Rat Model of Closed-Head Mild Traumatic Injury and its Validation

Animal models are crucial for advancing our understanding of mild traumatic brain injury (mTBI) and guiding clinical research. To achieve meaningful insights, developing a stable and reproducible animal model is essential. In this study, we report a detailed description of a closed-head mTBI model and a representative validation method using Sprague-Dawley rats to verify the modeling effect. The model involves dropping a 550 g mass weight from a height of 100 cm directly onto the head of a rat on a destructible surface, followed by a 180-degree turn. To assess the injury, rats underwent a series of neurobehavioral assessments 10 min post-injury, including time of loss of consciousness, first seeking-behavior time, escape ability, and beam balance ability test. During the acute and subacute stages following the injury, behavioral tests were conducted to assess motor coordination ability (Beam task), anxiety (Open Field test), and learning and memory abilities (Morris Water Maze test). The closed-head mTBI model produced a consistent injury response with minimal mortality and replicated real-life situations. The validation method effectively verified the model development and ensured the stability and consistency of the model.

Autore in primo piano: Avanzamento della ricerca sulle lesioni cerebrali traumatiche - Un modello a testa chiusa per una replicazione accurata e una valutazione rapida 

Here, we present a closed-head mild traumatic brain injury (mTBI) rat model and its validation exhibiting remarkable similarity to human mTBI concerning behavioral manifestations during the acute and subacute stages.

Modello di ratto di lesione traumatica lieve a testa chiusa e sua convalida

Animal models are crucial for advancing our understanding of mild traumatic brain injury (mTBI) and guiding clinical research. To achieve meaningful ...

Un modello Novel di Mild Traumatic Brain Injury per ratti giovani

Riepilogo

Esplora Altri Video

Capitoli in questo video

Rilevare i deficit comportamentistici in ratti dopo la ferita di cervello traumatica

Valutazione del comportamento dominante-sottomesso nei ratti adulti a seguito di trauma cranico

Un modello di mouse del singolo e ripetitivo dolore cerebrale traumatico lieve

Un nuovo e traslazionale modello di commozione cerebrale che combina forza e rotazione con la microdialisi cerebrale in vivo

Advanced Diffusion Imaging nell'ippocampo di ratti con lievi lesioni cerebrali traumatiche

Modello elettromagnetico controllato a testa chiusa di lieve lesione cerebrale traumatica nei topi

Valutazione dei cambiamenti nella plasticità sinaptica utilizzando un modello di trauma cranico chiuso sveglio di lieve lesione cerebrale traumatica

Modello di ratto di lesione traumatica lieve a testa chiusa e sua convalida

Modello di ratto di lesione traumatica lieve a testa chiusa e sua convalida

Modello di ratto di lesione traumatica lieve a testa chiusa e sua convalida