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 border="0" cellpadding="0" cellspacing="0" width="824">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">Brass Weights</td>
			<td style="width:155px;">Ginsberg Scientific</td>
			<td style="width:187px;">7-2500-2</td>
			<td style="width:219px;">Need to have metal loop attached to base</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">Alluminum Foil</td>
			<td style="width:155px;">Alcan</td>
			<td style="width:187px;"></td>
			<td>Available at most grocery stores</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">Masking Tape</td>
			<td style="width:155px;"></td>
			<td style="width:187px;"></td>
			<td>Commercially available&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">U-Shaped Plastic Stand</td>
			<td style="width:155px;"></td>
			<td style="width:187px;"></td>
			<td>Constructed by Laboratory</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">Clamp Stand</td>
			<td style="width:155px;">Sigma-Aldrich</td>
			<td style="width:187px;">Z190357</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">Plastic Guide Tube</td>
			<td style="width:155px;"></td>
			<td style="width:187px;"></td>
			<td>Could be constructed or purchased at a hardware store</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">Fishing Line</td>
			<td style="width:155px;">Angler 10lb&#160;</td>
			<td style="width:187px;"></td>
			<td>Purchased from a sporting goods retailer&#160;</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:264px;">Isoflurane</td>
			<td style="width:155px;">Pharmaceutical Partners of Canada</td>
			<td style="width:187px;">DIN 02237518</td>
			<td>Inhalation Anesthetic</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">Topical Lidocaine (30ml)</td>
			<td style="width:155px;">Astra Zeneca</td>
			<td style="width:187px;">DIN 0001694</td>
			<td>Xylocaine Jelly 2%&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">Cotton Swabs</td>
			<td style="width:155px;"></td>
			<td style="width:187px;"></td>
			<td>Commercially available&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">Heating Pad - 3 heat setting</td>
			<td style="width:155px;"></td>
			<td style="width:187px;"></td>
			<td>Commercially available&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">Stop Watch</td>
			<td style="width:155px;">Sportline</td>
			<td style="width:187px;">L303</td>
			<td>Purchased from a sporting goods retailer&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">Video Camera</td>
			<td style="width:155px;">Sony</td>
			<td style="width:187px;">HDR-CX260V</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:264px;">Sprague Dawley Rats</td>
			<td style="width:155px;">Charles River Laboratories</td>
			<td style="width:187px;">SAS SD 40</td>
			<td>Male and females ordered from Charles River Laboratories and pups bred in-house</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">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 ...

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23.4K 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

Acute and Chronic Tactile Sensory Testing after Spinal Cord Injury in Rats

Spinal cord injury (SCI) impairs sensory systems causing allodynia1-8. To identify cellular and molecular causes of allodynia, sensitive and valid sensory testing in rat SCI models is needed. However, until recently, no single testing approach had been validated for SCI so that standardized methods have not been implemented across labs. Additionally, available testing methods could not be implemented acutely or when severe motor impairments existed, preventing studies of the development of SCI-induced allodynia3. Here we present two validated sensory testing methods using von Frey Hair (VFH) monofilaments which quantify changes in tactile sensory thresholds after SCI4-5. One test is the well-established Up-Down test which demonstrates high sensitivity and specificity across different SCI severities when tested chronically5. The other test is a newly-developed dorsal VFH test that can be applied acutely after SCI when allodynia develops, prior to motor recovery4-5. Each VFH monofilament applies a calibrated force when touched to the skin of the hind paw until it bends. In the up-down method, alternating VFHs of higher or lower forces are used on the plantar L5 dermatome to delineate flexor withdrawal thresholds. Successively higher forces are applied until withdrawal occurs then lower force VFHs are used until withdrawal ceases. The tactile threshold reflects the force required to elicit withdrawal in 50% of the stimuli. For the new test, each VFH is applied to the dorsal L5 dermatome of the paw while the rat is supported by the examiner. The VFH stimulation occurs in ascending order of force until at least 2 of 3 applications at a given force produces paw withdrawal. Tactile sensory threshold is the lowest force to elicit withdrawal 66% of the time. Acclimation, testing and scoring procedures are described. Aberrant trials that require a retest and typical trials are defined. Animal use was approved by Ohio State University Animal Care and Use Committee.

We describe two tactile sensory testing methods for acute or chronic periods of spinal cord injury in rats. These validated procedures can detect the development and maintenance of allodynia-like sensations.

Acuta e Cronica test sensoriale tattile dopo lesione del midollo spinale in ratti

Spinal cord injury (SCI) impairs sensory systems causing allodynia1-8. To identify cellular and molecular causes of allodynia, sensitive and valid sensory ...

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Medicina

A Contusion Model of Severe Spinal Cord Injury in Rats

The translational potential of novel treatments should be investigated in severe spinal cord injury (SCI) contusion models. A detailed methodology is described to obtain a consistent model of severe SCI. Use of a stereotactic frame and computer controlled impactor allows for creation of reproducible injury. Hypothermia and urinary tract infection pose significant challenges in the post-operative period. Careful monitoring of animals with daily weight recording and bladder expression allows for early detection of post-operative complications. The functional results of this contusion model are equivalent to transection models. The contusion model can be utilized to evaluate the efficacy of both neuroprotective and neuroregenerative approaches.

A contusion model of severe spinal cord injury is described. Detailed pre-operative, operative and post-operative steps are described to obtain a consistent model.

Un modello Contusione di gravi lesioni del midollo spinale nei ratti

The translational potential of novel treatments should be investigated in severe spinal cord injury (SCI) contusion models. A detailed methodology is ...

A Novel Vertebral Stabilization Method for Producing  Contusive Spinal Cord Injury

Clinically-relevant animal cervical spinal cord injury (SCI) models are essential for developing and testing potential therapies; however, producing reliable cervical SCI is difficult due to lack of satisfactory methods of vertebral stabilization. The conventional method to stabilize the spine is to suspend the rostral and caudal cervical spine via clamps attached to cervical spinous processes. &#160;However, this method of stabilization fails to prevent tissue yielding during the contusion as the cervical spinal processes are too short to be effectively secured by the clamps (Figure 1). &#160;Here we introduce a new method to completely stabilize the cervical vertebra at the same level of the impact injury. &#160;This method effectively minimizes movement of the spinal column at the site of impact, which greatly improves the production of consistent SCIs. &#160;We provide visual description of the equipment (Figure 2-4), methods, and a step-by-step protocol for the stabilization of the cervical 5 vertebra (C5) of adult rats, to perform laminectomy (Figure 5) and produce a contusive SCI thereafter. &#160;Although we only demonstrate a cervical hemi-contusion using the NYU/MASCIS impactor device, this vertebral stabilization technique can be applied to other regions of the spinal cord, or be adapted to other SCI devices. &#160;Improving spinal cord exposure and fixation through vertebral stabilization may be valuable for producing consistent and reliable injuries to the spinal cord. &#160;This vertebral stabilization method can also be used for stereotactic injections of cells and tracers, and for imaging using two-photon microscopy in various neurobiological studies.

Vertebral stabilization is necessary for minimizing variability, and for producing consistent experimental spinal cord injuries.&#160; Using a customized stabilizing apparatus in conjunction with the NYU/MASCIS impactor device, we have demonstrated here the proper equipment and procedure for generating reproducible hemi-contusive cervical (C5) spinal cord injuries in adult rats.

A Novel vertebrale metodo di stabilizzazione per la produzione di Contusivi Cord Injury spinale

Clinically-relevant animal cervical spinal cord injury (SCI) models are essential for developing and testing potential therapies; however, producing ...

Stretch in Brain Microvascular Endothelial Cells (cEND) as an In Vitro Traumatic Brain Injury Model of the Blood Brain Barrier

Due to the high mortality incident brought about by traumatic brain injury (TBI), methods that would enable one to better understand the underlying mechanisms involved in it are useful for treatment. There are both in vivo and in vitro methods available for this purpose. In vivo models can mimic actual head injury as it occurs during TBI. However, in vivo techniques may not be exploited for studies at the cell physiology level. Hence, in vitro methods are more advantageous for this purpose since they provide easier access to the cells and the extracellular environment for manipulation.
Our protocol presents an in vitro model of TBI using stretch injury in brain microvascular endothelial cells. It utilizes pressure applied to the cells cultured in flexible-bottomed wells. The pressure applied may easily be controlled and can produce injury that ranges from low to severe. The murine brain microvascular endothelial cells (cEND) generated in our laboratory is a well-suited model for the blood brain barrier (BBB) thus providing an advantage to other systems that employ a similar technique. In addition, due to the simplicity of the method, experimental set-ups are easily duplicated. Thus, this model can be used in studying the cellular and molecular mechanisms involved in TBI at the BBB.

Stretch in Brain Microvascular Endothelial Cells cEND as an In Vitro Traumatic Brain Injury Model of the Blood Brain Barrier

In vitro traumatic brain injury models are being developed to reproduce in vivo brain deformation. Stretch-induced injury has been employed for astrocytes, neurons, glial cells, aortic, and brain endothelial cells. However, our system uses a blood brain barrier (BBB) model that possesses properties constituting a legitimate model of the BBB to establish an in vitro&#160;TBI model.

Stretch in microvascolari cerebrali cellule endoteliali (CEND) come<em&gt; In Vitro</em&gt; Trauma cranico modello della barriera ematoencefalica

Due to the high mortality incident brought about by traumatic brain injury (TBI), methods that would enable one to better understand the underlying ...

Controlled Cortical Impact Model for Traumatic Brain Injury

Every year over a million Americans suffer a traumatic brain injury (TBI). Combined with the incidence of TBIs worldwide, the physical, emotional, social, and economical effects are staggering. Therefore, further research into the effects of TBI and effective treatments is necessary. The controlled cortical impact (CCI) model induces traumatic brain injuries ranging from mild to severe. This method uses a rigid impactor to deliver mechanical energy to an intact dura exposed following a craniectomy. Impact is made under precise parameters at a set velocity to achieve a pre-determined deformation depth. Although other TBI models, such as weight drop and fluid percussion, exist, CCI is more accurate, easier to control, and most importantly, produces traumatic brain injuries similar to those seen in humans. However, no TBI model is currently able to reproduce pathological changes identical to those seen in human patients. The CCI model allows investigation into the short-term and long-term effects of TBI, such as neuronal death, memory deficits, and cerebral edema, as well as potential therapeutic treatments for TBI.

Traumatic brain injuries (TBIs) remain a serious health problem. Using the controlled cortical impact surgery model, research on the effects of TBI and possible treatment methods may be performed.

Controllata corticale modello Impact per trauma cranico

Every year over a million Americans suffer a traumatic brain injury (TBI).  Combined with the incidence of TBIs worldwide, the physical, emotional, ...

Renal Ischaemia Reperfusion Injury: A Mouse Model of Injury and Regeneration

Renal ischaemia reperfusion injury (IRI) is a common cause of acute kidney injury (AKI) in patients and occlusion of renal blood flow is unavoidable during renal transplantation. Experimental models that accurately and reproducibly recapitulate renal IRI are crucial in dissecting the pathophysiology of AKI and the development of novel therapeutic agents. Presented here is a mouse model of renal IRI that results in reproducible AKI. This is achieved by a midline laparotomy approach for the surgery with one incision allowing both a right nephrectomy that provides control tissue and clamping of the left renal pedicle to induce ischaemia of the left kidney. By careful monitoring of the clamp position and body temperature during the period of ischaemia this model achieves reproducible functional and structural injury. Mice sacrificed 24 hr&#160;following surgery demonstrate loss of renal function with elevation of the serum or plasma creatinine level as well as structural kidney damage with acute tubular necrosis evident. Renal function improves and the acute tissue injury resolves during the course of 7 days following renal IRI such that this model may be used to study renal regeneration. This model of renal IRI has been utilized to study the molecular and cellular pathophysiology of AKI as well as analysis of the subsequent renal regeneration.

The mouse model of renal ischaemia reperfusion injury described here comprises of a right nephrectomy that provides control tissue and clamping of the left renal pedicle to induce ischaemia that results in acute kidney injury. This model uses a midline laparotomy approach with all steps performed via one incision.

Renale ischemia riperfusione: un modello murino di infortuni e rigenerazione

Renal ischaemia reperfusion injury (IRI) is a common cause of acute kidney injury (AKI) in patients and occlusion of renal blood flow is unavoidable ...

A Tissue Displacement-based Contusive Spinal Cord Injury Model in Mice

Producing a consistent and reproducible contusive spinal cord injury (SCI) is critical to minimizing behavioral and histological variabilities between experimental animals. Several contusive SCI models have been developed to produce injuries using different mechanisms. The severity of the SCI is based on the height that a given weight is dropped, the injury force, or the spinal cord displacement. In the current study, we introduce a novel mouse contusive SCI device, the Louisville Injury System Apparatus (LISA) impactor, which can create a displacement-based SCI with high injury velocity and accuracy. This system utilizes laser distance sensors combined with advanced software to produce graded and highly-reproducible injuries. We performed a contusive SCI at the 10th thoracic vertebral (T10) level in mice to demonstrate the step-by-step procedure. The model can also be applied to the cervical and lumbar spinal levels.

We introduce a tissue displacement-based contusive spinal cord injury model that can produce a consistent contusive spinal cord injury in adult mice.

Un modello di lesioni del midollo spinale contusivo basato sullo spostamento tissutale nei topi

Producing a consistent and reproducible contusive spinal cord injury (SCI) is critical to minimizing behavioral and histological variabilities between ...

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 ...

Spinal Cord Lateral Hemisection and Asymmetric Behavioral Assessments in Adult Rats

Incomplete spinal cord injury (SCI) often leads to impairments of sensorimotor functions and is clinically the most frequent type of SCI. Human Brown-S&#233;quard syndrome&#160;is a common type of incomplete SCI caused by a lesion to one half of the spinal cord which results in paralysis and loss of&#160;proprioception&#160;on the same (or ipsilesional) side as the injury, and loss of pain and temperature sensation on the opposite (or contralesional) side. Adequate methodologies for producing a spinal cord lateral hemisection (HX) and assessing neurological impairments are essential to establish a reliable animal model of Brown-S&#233;quard syndrome. Although lateral hemisection model plays a pivotal role in basic and translational research, standardized protocols for creating such a hemisection and assessing unilateralized function are lacking. The goal of this study is to describe step-by-step procedures to produce a rat spinal lateral HX at the 9th thoracic (T9) vertebral level. We, then, describe a combined behavior scale for HX (CBS-HX) that provides a simple and sensitive assessment of asymmetric neurological performance for unilateral SCI. The CBS-HX, ranging from 0 to 18, is composed of 4 individual assessments which include unilateral hindlimb stepping (UHS), coupling, contact placing, and grid walking. For CBS-HX, the ipsilateral and contralateral hindlimbs are assessed separately. We found that, after a T9 HX, the ipsilateral hindlimb showed impaired behavior function whereas the contralateral hindlimb showed substantial recovery. The CBS-HX effectively discriminated behavioral functions between ipsilateral and contralateral hindlimbs and detected temporal progression of recovery of the ipsilateral hindlimb. The CBS-HX components can be analyzed separately or in combination with other measures when needed. Although we only provided visual descriptions of the surgical procedures and behavioral assessments of a thoracic HX, the principle may be applied to other incomplete SCIs and at other levels of the injury.

Here we describe surgical procedures to produce a reliable spinal cord lateral hemisection (HX) at the 9th thoracic level in adult rats and neurobehavioral assessments designed for detecting asymmetric deficits after such a unilateral injury.

Emisezione laterale del cavo spinale e valutazioni comportamentali asimmetriche nei ratti adulti

Incomplete spinal cord injury (SCI) often leads to impairments of sensorimotor functions and is clinically the most frequent type of SCI. Human ...

Semi-quantitative Assessment Using [18F]FDG Tracer in Patients with Severe Brain Injury

Patients with severe traumatic brain injury (sTBI) have difficulty knowing whether they are accurately expressing their thoughts and emotions because of disorders of consciousness, disrupted higher brain function, and verbal disturbances. As a consequence of an insufficient ability to communicate, objective evaluations are needed from family members, medical staff, and caregivers. One such evaluation is the assessment of functioning brain areas. Recently, multimodal brain imaging has been used to explore the function of damaged brain areas. [18F]-fluorodeoxyglucose positron emission tomography-computed tomography ([18F]FDG-PET/CT) is a successful tool for examining brain function. However, the assessment of brain glucose metabolism based on [18F]FDG-PET/CT is not standardized and depends on several varying parameters, as well as the patient&#39;s condition. Here, we describe a series of semiquantitative assessment protocols for a region-of-interest (ROI) image analysis using self-produced [18F]FDG tracers in patients with sTBI. The protocol focuses on screening the participants, preparing the [18F]FDG tracer in the hot lab, scheduling the acquisition of [18F]FDG-PET/CT brain images, and measuring glucose metabolism using the ROI analysis from a targeted brain area.

Semi-quantitative Assessment Using [18F]FDG Tracer in Patients with Severe Brain Injury

[18F]-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography is useful for studying glucose metabolism related to brain function. Here, we present a protocol for an [18F]FDG tracer set-up and semiquantitative assessment of the region-of-interest analysis for targeted brain areas associated with clinical manifestations in patients with severe traumatic brain injury.

Valutazione semi-quantitativa utilizzando [18F] FDG Tracer in pazienti con trauma cranico severo

Patients with severe traumatic brain injury (sTBI) have difficulty knowing whether they are accurately expressing their thoughts and emotions because of ...