Name: a model of long-term ventricular fibrillation in isolated rat hearts
Uploaded: 2023-02-17T14:15:00
Description: Watch this Scientific Journal Video about A Model of Long-Term Ventricular Fibrillation in Isolated Rat Hearts at JoVE.com

Questo lavoro è stato svolto con il supporto di Cardiovascular Surgery, First Medical Center, Chinese PLA General Hospital e Laboratory Animal Center, Chinese PLA General Hospital.

Tutte le procedure sperimentali e i protocolli utilizzati in questa indagine sono stati esaminati e approvati dal Comitato per la cura e l'uso degli animali dell'ospedale generale del PLA.
1. Preparazione dell'apparecchio di Langendorff
<ol><li>Preparare il buffer Krebs-Henseleit (K-H). Per preparare il tampone K-H, aggiungere quanto segue all'acqua distillata: 118,0 mM NaCl, 4,7 mM KCl, 1,2 mM MgSO 4, 1,2 mM NaH 2 PO4, 1,8 mM CaCl2, 25,0 mM ...

<ol>
	<li>Kilic, 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=Clinical+outcomes+of+mitral+valve+reoperations+in+the+United+States:+An+analysis+of+the+society+of+thoracic+surgeons+national+database.">Clinical outcomes of mitral valve reoperations in the United States: An analysis of the society of thoracic surgeons national database.</a> The Annals of Thoracic Surgery. 107 (3), 754-759 (2019).</li><li>Akins, C. W., 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=Risk+of+reoperative+valve+replacement+for+failed+mitral+and+aortic+bioprostheses.">Risk of reoperative valve replacement for failed mitral and aortic bioprostheses.</a> The Annals of Thoracic Surgery. 65 (6), 1551-1542 (1998).</li><li>Jamieson, W. R., 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=Reoperation+for+bioprosthetic+mitral+structural+failure:+risk+assessment.">Reoperation for bioprosthetic mitral structural failure: risk assessment.</a> Circulation. 108 (Suppl 1), 98 (2003).</li><li>Seeburger, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Minimally+invasive+mitral+valve+surgery+after+previous+sternotomy:+Experience+in+181+patients.">Minimally invasive mitral valve surgery after previous sternotomy: Experience in 181 patients.</a> The Annals of Thoracic Surgery. 87 (3), 709-714 (2009).</li><li>Arcidi, J. 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=Fifteen-year+experience+with+minimally+invasive+approach+for+reoperations+involving+the+mitral+valve.">Fifteen-year experience with minimally invasive approach for reoperations involving the mitral valve.</a> The Journal of Thoracic and Cardiovascular Surgery. 143 (5), 1062-1068 (2012).</li><li>Cox, J. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+safety+of+induced+ventricular+fibrillation+during+cardiopulmonary+bypass+in+nonhypertrophied+hearts.">The safety of induced ventricular fibrillation during cardiopulmonary bypass in nonhypertrophied hearts.</a> The Journal of Thoracic and Cardiovascular Surgery. 74 (3), 423-432 (1977).</li><li>Schraut, W., Lamberti, J. J., Kampman, K., Glagov, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ventricular+fibrillation+during+cardiopulmonary+bypass:+Long-term+effects+on+myocardial+morphology+and+function.">Ventricular fibrillation during cardiopulmonary bypass: Long-term effects on myocardial morphology and function.</a> The Annals of Thoracic Surgery. 27 (3), 230-234 (1979).</li><li>Li, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pravastatin+attenuates+cardiac+dysfunction+induced+by+lysophosphatidylcholine+in+isolated+rat+hearts.">Pravastatin attenuates cardiac dysfunction induced by lysophosphatidylcholine in isolated rat hearts.</a> European Journal of Pharmacology. 640 (1-3), 139-142 (2010).</li><li>Lang, S., 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=CXCL10/IP-10+neutralization+can+ameliorate+lipopolysaccharide-induced+acute+respiratory+distress+syndrome+in+rats.">CXCL10/IP-10 neutralization can ameliorate lipopolysaccharide-induced acute respiratory distress syndrome in rats.</a> PLoS One. 12 (1), e0169100 (2017).</li><li>Lubbe, W. F., Bricknell, O. L., Marzagao, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ventricular+fibrillation+threshold+and+vulnerable+period+in+the+isolated+perfused+rat+heart.">Ventricular fibrillation threshold and vulnerable period in the isolated perfused rat heart.</a> Cardiovascular Research. 9 (5), 613-620 (1975).</li><li>Hottentrott, C. E., Towers, B., Kurkji, H. J., Maloney, J. V., Buckberg, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+hazard+of+ventricular+fibrillation+in+hypertrophied+ventricles+during+cardiopulmonary+bypass.">The hazard of ventricular fibrillation in hypertrophied ventricles during cardiopulmonary bypass.</a> The Journal of Thoracic and Cardiovascular Surgery. 66 (5), 742-753 (1973).</li><li>Hottenrott, C., Maloney, J. V., Buckberg, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Studies+of+the+effects+of+ventricular+fibrillation+on+the+adequacy+of+regional+myocardial+flow.+I.+Electrical+vs.+spontaneous+fibrillation.">Studies of the effects of ventricular fibrillation on the adequacy of regional myocardial flow. I. Electrical vs. spontaneous fibrillation.</a> The Journal of Thoracic and Cardiovascular Surgery. 68 (4), 615-625 (1974).</li><li>Buckberg, G. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Studies+of+the+effects+of+hypothermia+on+regional+myocardial+blood+flow+and+metabolism+during+cardiopulmonary+bypass.+I.+The+adequately+perfused+beating,+fibrillating,+and+arrested+heart.">Studies of the effects of hypothermia on regional myocardial blood flow and metabolism during cardiopulmonary bypass. I. The adequately perfused beating, fibrillating, and arrested heart.</a> The Journal of Thoracic and Cardiovascular Surgery. 73 (1), 87-94 (1977).</li><li>Gazmuri, R. J., Berkowitz, M., Cajigas, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Myocardial+effects+of+ventricular+fibrillation+in+the+isolated+rat+heart.">Myocardial effects of ventricular fibrillation in the isolated rat heart.</a> Critical Care Medicine. 27 (8), 1542-1550 (1999).</li><li>Clasen, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+modified+approach+for+programmed+electrical+stimulation+in+mice:+Inducibility+of+ventricular+arrhythmias.">A modified approach for programmed electrical stimulation in mice: Inducibility of ventricular arrhythmias.</a> PLoS One. 13 (8), e0201910 (2018).</li><li>Diaz-Maue, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Advanced+cardiac+rhythm+management+by+applying+optogenetic+multi-site+photostimulation+in+murine+hearts.">Advanced cardiac rhythm management by applying optogenetic multi-site photostimulation in murine hearts.</a> Journal of Visualized Experiments. (174), e62335 (2021).</li><li>Jungen, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impact+of+intracardiac+neurons+on+cardiac+electrophysiology+and+arrhythmogenesis+in+an+ex+vivo+Langendorff+system.">Impact of intracardiac neurons on cardiac electrophysiology and arrhythmogenesis in an ex vivo Langendorff system.</a> Journal of Visualized Experiments. 135, e57617 (2018).</li><li>Koretsune, Y., Marban, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+calcium+in+the+pathophysiology+of+ventricular+fibrillation+and+in+the+pathogenesis+of+postarrhythmic+contractile+dysfunction.">Cell calcium in the pathophysiology of ventricular fibrillation and in the pathogenesis of postarrhythmic contractile dysfunction.</a> Circulation. 80 (2), 369-379 (1989).</li><li>Brazier, J. R., Cooper, N., McConnell, D. H., Buckberg, G. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Studies+of+the+effects+of+hypothermia+on+regional+myocardial+blood+flow+and+metabolism+during+cardiopulmonary+bypass.+III.+Effects+of+temperature,+time,+and+perfusion+pressure+in+fibrillating+hearts.">Studies of the effects of hypothermia on regional myocardial blood flow and metabolism during cardiopulmonary bypass. III. Effects of temperature, time, and perfusion pressure in fibrillating hearts.</a> The Journal of Thoracic and Cardiovascular Surgery. 73 (1), 102-109 (1977).</li><li>von Planta, I., 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=Cardiopulmonary+resuscitation+in+the+rat.">Cardiopulmonary resuscitation in the rat.</a> Journal of Applied Physiology. 65 (6), 2641-2647 (1988).</li><li>Luo, X., 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=Ageing+increases+cardiac+electrical+remodelling+in+rats+and+mice+via+NOX4/ROS/CaMKII-mediated+calcium+signalling.">Ageing increases cardiac electrical remodelling in rats and mice via NOX4/ROS/CaMKII-mediated calcium signalling.</a> Oxidative Medicine and Cellular Longevity. 2022, 8538296 (2022).</li><li>Hohnloser, S., Weirich, J., Antoni, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+direct+current+on+the+electrical+activity+of+the+heart+and+on+its+susceptibility+to+ventricular+fibrillation.">Influence of direct current on the electrical activity of the heart and on its susceptibility to ventricular fibrillation.</a> Basic Research in Cardiology. 77 (3), 237-249 (1982).</li><li>Xie, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-energy+defibrillation+increases+the+severity+of+postresuscitation+myocardial+dysfunction.">High-energy defibrillation increases the severity of postresuscitation myocardial dysfunction.</a> Circulation. 96 (2), 683-688 (1997).</li><li>Manoach, M., Netz, H., Erez, M., Weinstock, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ventricular+self-defibrillation+in+mammals:+Age+and+drug+dependence.">Ventricular self-defibrillation in mammals: Age and drug dependence.</a> Age and Ageing. 9 (2), 112-116 (1980).</li><li>Filippi, S., Gizzi, A., Cherubini, C., Luther, S., Fenton, F. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanistic+insights+into+hypothermic+ventricular+fibrillation:+The+role+of+temperature+and+tissue+size.">Mechanistic insights into hypothermic ventricular fibrillation: The role of temperature and tissue size.</a> Europace. 16 (3), 424-434 (2014).</li></ol>

Questo protocollo stabilisce un modello animale di VF a lungo termine in cuori di ratto isolati che non è stato precedentemente segnalato. Inoltre, in questo studio sono state confrontate diverse condizioni di stimolazione elettrica. Questo studio fornisce un modello per gli studi relativi all'arresto della fibrillazione ventricolare durante la cardiochirurgia.
Il tasso di successo del modello è un indicatore molto importante correlato al personale, al tempo e ai costi economici. Nei modelli...

La cardiochirurgia viene solitamente eseguita tramite toracotomia, con blocco dell'aorta e perfusione con una soluzione cardioplegica per arrestare il cuore. La chirurgia cardiaca ripetuta può essere più impegnativa dell'intervento chirurgico iniziale, con complicanze e tassi di mortalità più elevati 1,2,3. Inoltre, l'approccio convenzionale della sternotomia mediana può causare danni ai vasi ponte dietro lo sterno, all'aorta ascendente, al ventricolo destro e ad altre strutture importanti. Sanguinamento esteso dovuto alla separazione del tessuto connettivo, infezione della ferita sternale e osteomielite sternale dovuta a sternotomia sono tutte possibili complicanze. La dissezione estesa aumenta il rischio di lesioni ed emorragie nelle strutture cardiache vitali.
Con lo sviluppo della cardiochirurgia minimamente invasiva, le incisioni sono diventate più piccole e l'arresto cardiaco è talvolta difficile da raggiungere. La chirurgia cardiaca ripetuta sotto fibrillazione ventricolare (VF)4,5 è sicura, fattibile e può fornire una migliore protezione miocardica. Pertanto, questo protocollo introduce il metodo di arresto cardiaco VF in chirurgia con circolazione extracorporea minimamente invasiva. Il cuore perde una contrazione efficace durante la VF e, quindi, non è necessario suturare e bloccare l'aorta ascendente durante l'intervento chirurgico, il che semplifica la procedura. Tuttavia, anche se il cuore è continuamente perfuso, VF a lungo termine può ancora essere dannoso per il cuore.
Man mano che questo metodo diventa più ampiamente utilizzato, la questione di come proteggere il cuore durante la VF diventa sempre più rilevante. Ciò richiederà studi approfonditi e approfonditi utilizzando modelli animali di VF a lungo termine. In passato, la ricerca in questo campo ha utilizzato principalmente animali di grossa taglia6,7 e ha richiesto la cooperazione tra chirurghi, anestesisti, perfusionisti e altri ricercatori. Questi studi hanno richiesto troppo tempo, le dimensioni del campione erano spesso piccole e gli studi si sono generalmente concentrati sulla funzione cardiaca e meno sulle valutazioni meccanicistiche e molecolari. Ad oggi, nessuno studio ha riportato un protocollo dettagliato per stabilire un modello VF a lungo termine.
Questo protocollo, quindi, fornisce i dettagli necessari per sviluppare un modello di ratto VF a lungo termine utilizzando l'apparato di Langendorff. Il protocollo è semplice, economico, ripetibile e stabile.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>0 Non-absorbable suture</td>
			<td>Ethicon, Inc.</td>
			<td></td>
			<td>Preparation of the isolated heart</td>
		</tr>
		<tr>
			<td>95% O2 + 5% CO2</td>
			<td>Beijing BeiYang United Gas Co., Ltd.&#160;</td>
			<td></td>
			<td>K-H buffer</td>
		</tr>
		<tr>
			<td>AcqKnowledge software</td>
			<td>BIOPAC Systems Inc.</td>
			<td>Version 4.2.1</td>
			<td>Software</td>
		</tr>
		<tr>
			<td>Automatic biochemistry analyzer</td>
			<td>Rayto Life and Analytical Sciences Co., Ltd.</td>
			<td>Chemray 800</td>
			<td>CK-MB assay</td>
		</tr>
		<tr>
			<td>BIOPAC research systems</td>
			<td>BIOPAC Systems Inc.</td>
			<td>MP150</td>
			<td>Hardware</td>
		</tr>
		<tr>
			<td>Blunt needle (20 G, TWLB)</td>
			<td>Tianjin Hanaco MEDICAL Co., Ltd.</td>
			<td>H-113AP-S</td>
			<td>Modified Langendorff perfusion system</td>
		</tr>
		<tr>
			<td>Calcium chloride</td>
			<td>Sinopharm Chemical Reagent Co.,Ltd</td>
			<td>10005861</td>
			<td>K-H buffer</td>
		</tr>
		<tr>
			<td>CK-MB assay kits&#160;</td>
			<td>Changchun Huili Biotech Co., Ltd.</td>
			<td>C060</td>
			<td>CK-MB assay</td>
		</tr>
		<tr>
			<td>Curved forcep</td>
			<td>Shanghai Medical Instrument (Group) Co., Ltd.</td>
			<td></td>
			<td>Preparation of the isolated heart</td>
		</tr>
		<tr>
			<td>EDTA</td>
			<td>Sinopharm Chemical Reagent Co.,Ltd</td>
			<td>10009717</td>
			<td>K-H buffer</td>
		</tr>
		<tr>
			<td>Electrical stimulator</td>
			<td>BIOPAC Systems Inc.</td>
			<td>STEMISOC</td>
			<td>Hardware</td>
		</tr>
		<tr>
			<td>Filter</td>
			<td>Tianjin Hanaco MEDICAL Co., Ltd.</td>
			<td>H-113AP-S</td>
			<td></td>
		</tr>
		<tr>
			<td>Glucose</td>
			<td>Sinopharm Chemical Reagent Co.,Ltd</td>
			<td>63005518</td>
			<td>K-H buffer</td>
		</tr>
		<tr>
			<td>Heparin sodium</td>
			<td>Tianjin Biochem Pharmaceutical Co., Ltd.</td>
			<td>H120200505</td>
			<td>Preparation of the isolated heart</td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>RWD Life Science Co.,LTD</td>
			<td>21082201</td>
			<td>Preparation of the isolated heart</td>
		</tr>
		<tr>
			<td>Magnesium sulfate</td>
			<td>Sinopharm Chemical Reagent Co.,Ltd</td>
			<td>20025118</td>
			<td>K-H buffer</td>
		</tr>
		<tr>
			<td>Needle electrodes</td>
			<td>BIOPAC Systems Inc.</td>
			<td>EL452</td>
			<td>Hardware</td>
		</tr>
		<tr>
			<td>Ophthalmic clamp</td>
			<td>Shanghai Medical Instrument (Group) Co., Ltd.</td>
			<td></td>
			<td>Preparation of the isolated heart</td>
		</tr>
		<tr>
			<td>Ophthalmic forceps</td>
			<td>Shanghai Medical Instrument (Group) Co., Ltd.</td>
			<td></td>
			<td>Preparation of the isolated heart</td>
		</tr>
		<tr>
			<td>Ophthalmic scissors</td>
			<td>Shanghai Medical Instrument (Group) Co., Ltd.</td>
			<td></td>
			<td>Preparation of the isolated heart</td>
		</tr>
		<tr>
			<td>Perfusion tube</td>
			<td>Tianjin Hanaco MEDICAL Co., Ltd.</td>
			<td>H-113AP-S</td>
			<td>Modified Langendorff perfusion system</td>
		</tr>
		<tr>
			<td>Potassium chloride</td>
			<td>Sinopharm Chemical Reagent Co.,Ltd</td>
			<td>10016318</td>
			<td>K-H buffer</td>
		</tr>
		<tr>
			<td>Sodium bicarbonate</td>
			<td>Sinopharm Chemical Reagent Co.,Ltd</td>
			<td>10018960</td>
			<td>K-H buffer</td>
		</tr>
		<tr>
			<td>Sodium chloride</td>
			<td>Sinopharm Chemical Reagent Co.,Ltd</td>
			<td>10019318</td>
			<td>K-H buffer</td>
		</tr>
		<tr>
			<td>Sodium dihydrogen phosphate dihydrate</td>
			<td>Sinopharm Chemical Reagent Co.,Ltd</td>
			<td>20040718</td>
			<td>K-H buffer</td>
		</tr>
		<tr>
			<td>Sprague-Dawley (SD) rats</td>
			<td>SPF (Beijing) biotechnology Co., Ltd.</td>
			<td>Male, 300-350g</td>
			<td>Preparation of the isolated heart</td>
		</tr>
		<tr>
			<td>Thermometer</td>
			<td>Jiangsu Jingchuang Electronics Co., Ltd.</td>
			<td>GSP-6</td>
			<td>Modified Langendorff perfusion system</td>
		</tr>
		<tr>
			<td>Tissueforceps</td>
			<td>Shanghai Medical Instrument (Group) Co., Ltd.</td>
			<td></td>
			<td>Preparation of the isolated heart</td>
		</tr>
		<tr>
			<td>Tissue scissors</td>
			<td>Shanghai Medical Instrument (Group) Co., Ltd.</td>
			<td></td>
			<td>Preparation of the isolated heart</td>
		</tr>
		<tr>
			<td>Toothed forceps</td>
			<td>Shanghai Medical Instrument (Group) Co., Ltd.</td>
			<td></td>
			<td>Preparation of the isolated heart</td>
		</tr>
		<tr>
			<td>Ventilator</td>
			<td>Chengdu Instrument Factory</td>
			<td>DKX-150</td>
			<td>Preparation of the isolated heart</td>
		</tr>
		<tr>
			<td>Water bath1</td>
			<td>Ningbo Scientz Biotechnology Co.,Ltd.</td>
			<td>SC-15</td>
			<td>Modified Langendorff perfusion system</td>
		</tr>
		<tr>
			<td>Water bath2</td>
			<td>Shanghai Yiheng Technology Instrument Co., Ltd.</td>
			<td>DK-8D</td>
			<td>Modified Langendorff perfusion system</td>
		</tr>
	</tbody>
</table>

a model of long-term ventricular fibrillation in isolated rat hearts

La fibrillazione ventricolare (VF) è un'aritmia fatale con un'alta incidenza nei pazienti cardiaci, ma l'arresto VF sotto perfusione è un metodo trascurato di arresto intraoperatorio nel campo della cardiochirurgia. Con i recenti progressi nella cardiochirurgia, la domanda di studi VF prolungati sotto perfusione è aumentata. Tuttavia, il campo manca di modelli animali semplici, affidabili e riproducibili di fibrillazione ventricolare cronica. Questo protocollo induce VF a lungo termine attraverso la stimolazione elettrica a corrente alternata (AC) dell'epicardio. Diverse condizioni sono state utilizzate per indurre VF, tra cui la stimolazione continua con una bassa o alta tensione per indurre VF a lungo termine e la stimolazione per 5 minuti con una bassa o alta tensione per indurre VF spontanea a lungo termine. Sono stati confrontati i tassi di successo delle diverse condizioni, nonché i tassi di lesioni miocardiche e recupero della funzione cardiaca. I risultati hanno mostrato che la stimolazione continua a bassa tensione ha indotto VF a lungo termine e che 5 minuti di stimolazione a bassa tensione hanno indotto VF spontanea a lungo termine con lieve danno miocardico e un alto tasso di recupero della funzione cardiaca. Tuttavia, il modello VF a bassa tensione, continuamente stimolato a lungo termine, ha avuto un tasso di successo più elevato. La stimolazione ad alta tensione ha fornito un più alto tasso di induzione VF, ma ha mostrato un basso tasso di successo della defibrillazione, scarso recupero della funzione cardiaca e gravi lesioni del miocardio. Sulla base di questi risultati, la stimolazione epicardica AC continua a bassa tensione è raccomandata per il suo alto tasso di successo, stabilità, affidabilità, riproducibilità, basso impatto sulla funzione cardiaca e lieve danno miocardico.

Un totale di 57 ratti sono stati utilizzati negli esperimenti, di cui 30 hanno soddisfatto i criteri di inclusione. Gli animali inclusi sono stati divisi in cinque gruppi, con sei animali in ciascun gruppo: il gruppo di controllo (Gruppo C), il gruppo VF a lungo termine continuamente stimolato a bassa tensione (Gruppo LC), il gruppo VF a lungo termine stimolato continuamente ad alta tensione (Gruppo HC), il gruppo VF spontaneo a lungo termine indotto da bassa tensione (Gruppo LI) e il gruppo VF spontaneo a lungo termine ...

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A Model of Long-Term Ventricular Fibrillation in Isolated Rat Hearts

Questo protocollo presenta un modello di fibrillazione ventricolare a lungo termine nei cuori di ratto indotta dalla stimolazione continua con corrente alternata a bassa tensione. Questo modello ha un alto tasso di successo, è stabile, affidabile e riproducibile, ha un basso impatto sulla funzione cardiaca e causa solo lievi lesioni miocardiche.

Un modello di fibrillazione ventricolare a lungo termine in cuori di ratto isolati

Ventricular fibrillation (VF) is a fatal arrhythmia with a high incidence in cardiac patients, but VF arrest under perfusion is a neglected method of ...

Questo protocollo fornisce una necessità dettagliata di sviluppare un modello di ratto di fibrillazione ventricolare a lungo termine utilizzando l'apparato di Langendorff. Riempie il divario della fibrillazione ventricolare a lungo termine nel modello di piccolo animale. Il tecnico è semplice, economico, ripetibile e stabile.Questa tecnica può essere utilizzata nello studio dell'arresto della fibrillazione ventricolare sotto perfusione che viene eseguito in determinate situazioni cliniche nel campo delle sessioni e delle operazioni di cardiochirurgia. Per iniziare, preparare il tampone Krebs-Henseleit o KH aggiungendo 118 millimolari di cloruro di sodio, 4,7 millimolari di cloruro di potassio, 1,2 millimolare di cloruro di magnesio, 1,2 millimolare di sodio diidrogeno fosfato, 1,8 millimolare di cloruro di calcio, 25 millimolare di bicarbonato di sodio, 11,1 millimolare di glucosio e 0,5 millimolare EDTA in acqua distillata. Quindi preparare il sistema di perfusione Langendorff modificato.Gassare continuamente il pallone contenente tampone KH con il 95% di ossigeno e il 5% di anidride carbonica ad una pressione di circa 80 millimetri di mercurio. Posizionare un'estremità del tubo di perfusione nel tampone KH, far passare il centro del tubo di perfusione attraverso il bagno d'acqua e collegare un ago smussato da 20 gauge all'altra estremità del tubo di perfusione. Dopo aver sospeso l'ago su un supporto di filo, regolare la temperatura del bagno d'acqua in modo che la temperatura del tampone KH dall'estremità del sistema di perfusione sia di 37 gradi Celsius.Utilizzare un registratore di segnali fisiologico per digitalizzare e registrare tutti i segnali analogici. Utilizzare due elettrodi ad ago in acciaio inossidabile per registrare un elettrocardiogramma bipolare o ECG e due elettrodi ad ago in acciaio inossidabile per la stimolazione elettrica. Collegare un'estremità dei quattro elettrodi al registratore di segnali fisiologici e l'altra estremità vicino all'area in cui verrà posizionato il cuore dopo il collegamento all'apparecchio.Quindi, utilizzare il software del laptop per riconoscere, regolare e registrare automaticamente i parametri ECG ed emodinamici bipolari. Impostare i parametri dello stimolatore elettrico su corrente alternata a 30 hertz con il gruppo di bassa tensione che riceve 2 volt e il gruppo ad alta tensione che riceve 6 volt. Con il ratto anestetizzato collegato a un ventilatore dopo la dissezione cervicale e l'intubazione tracheale, sollevare la pelle dal processo xifoideo con una pinza dentata e fare un'incisione trasversale di tre centimetri nella pelle con forbici di tessuto.Estendi la pelle e le incisioni costali alle ascelle su entrambi i lati a forma di V. Utilizzare la dissezione smussata per separare il tronco brachiocefalico dal tessuto circostante. Quindi bloccare il tronco brachiocefalo con una pinza curva per facilitare la rimozione del cuore.Immergere immediatamente il cuore in una capsula di Petri con tampone KH da 0 a 4 gradi Celsius per lavare e pompare fuori il sangue residuo. Trasferire il cuore in una seconda capsula di Petri. Tagliare il tessuto ridondante e identificare l'aorta.Utilizzare due pinze oftalmiche per sollevare l'aorta e inserire l'aorta nell'ago smussato dell'apparato di Langendorff. Quindi, con l'aiuto di un assistente, legare un nodo con un filo di sutura 0. Accendere il regolatore di flusso di perfusione.Spingere il palloncino attraverso la valvola mitrale nel ventricolo sinistro. Riempire il palloncino con acqua distillata per ottenere una pressione diastolica finale da 5 a 10 millimetri di mercurio. Collegare l'ECG e gli elettrodi di stimolazione elettrica al cuore.Posizionare il cuore al centro della camera di vetro incamiciata mantenuta a 37 gradi Celsius. Lasciare che il cuore si equilibri per 20 minuti all'interno della camera. Quindi regolare la temperatura del bagno d'acqua per mantenere la temperatura all'interno della camera di vetro incamiciata a 30 gradi Celsius.Dopo che la temperatura ha raggiunto il livello desiderato, attivare l'interruttore di stimolazione elettrica sul software del laptop. Se l'animale fa parte della fibrillazione ventricolare a lungo termine continuamente stimolata o del gruppo VF, consentire 90 minuti di stimolazione elettrica. Dopo 90 minuti di VF, utilizzare elettrodi per fornire 0,1 joule di defibrillazione a corrente continua.Contemporaneamente, regolare la temperatura del bagno d'acqua per consentire alla temperatura di salire lentamente all'interno della camera di vetro incamiciata a 37 gradi Celsius per 10 minuti. Dopo la defibrillazione, lasciare battere il cuore per 60 minuti e poi interrompere il battito mediante perfusione lenta con cloruro di potassio al 10% a circa 37 gradi Celsius. Rimuovere il cuore per la creatina chinasi o il test CK-MB e l'analisi istologica.I tassi di VF, il tasso di successo della defibrillazione e il tasso di successo del modello VF sono mostrati qui. Il Gruppo LC e il Gruppo HC hanno ricevuto una stimolazione elettrica continua e quindi la VF si è verificata con un tasso di successo del 100%. Ma il gruppo HC ha dimostrato tassi di successo più bassi per la defibrillazione.Il gruppo LI e il gruppo HI in cui la stimolazione elettrica è stata disattivata dopo cinque minuti avevano tassi diversi di VF, ma il tasso di VF era più lento in entrambi i gruppi rispetto al gruppo LC e al gruppo HC. Sia il Gruppo LC che il Gruppo LI hanno avuto migliori tassi di successo della defibrillazione. Ma nel complesso, il Gruppo LC ha avuto il più alto tasso di successo del modello, mentre il Gruppo LI ha avuto un tasso di successo del modello inferiore. La frequenza cardiaca o FC, il flusso coronarico o FC e la differenza di pressione ventricolare sinistra o i tassi di recupero LVPD sono mostrati qui.L'emodinamica del gruppo C è rimasta stabile durante l'esperimento e ha mostrato una leggera diminuzione di HR, FC e LVPD. I due gruppi con VF indotta a bassa tensione avevano prestazioni simili e un buon tasso di recupero. L'HR e LVPD non erano significativamente diversi in quei gruppi rispetto al Gruppo C.Ma il tasso di recupero della FC era significativamente migliore rispetto al Gruppo C.In al contrario, il tasso di recupero emodinamico dei due gruppi con alta tensione indotta a VF a lungo termine era scarso e il gruppo VF a lungo termine continuamente stimolato ad alta tensione mostrava il peggior tasso di recupero.L'analisi dei fluidi di versamento coronarico ha mostrato che i livelli di CK-MB erano più alti in entrambi i gruppi ad alta tensione. Non sono state riscontrate differenze tra i due gruppi a bassa tensione e la colorazione del gruppo C.La colorazione con ematossilina ed eosina ha mostrato una regione di bruciatura dell'elettrodo nel gruppo HC. Questo protocollo è adatto per lo studio relativo all'arresto della fibrillazione ventricolare e alla perfusione in chirurgia cardiovascolare.

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Research

JoVE Journal

Medicine

Assessment of Cardiac Function and Energetics in Isolated Mouse Hearts Using 31P NMR Spectroscopy

Bioengineered mouse models have become powerful research tools in determining causal relationships between molecular alterations and models of cardiovascular disease. Although molecular biology is necessary in identifying key changes in the signaling pathway, it is not a surrogate for functional significance. While physiology can provide answers to the question of function, combining physiology with biochemical assessment of metabolites in the intact, beating heart allows for a complete picture of cardiac function and energetics. For years, our laboratory has utilized isolated heart perfusions combined with nuclear magnetic resonance (NMR) spectroscopy to accomplish this task. Left ventricular function is assessed by Langendorff-mode isolated heart perfusions while cardiac energetics is measured by performing 31P magnetic resonance spectroscopy of the perfused hearts. With these techniques, indices of cardiac function in combination with levels of phosphocreatine and ATP can be measured simultaneously in beating hearts. Furthermore, these parameters can be monitored while physiologic or pathologic stressors are instituted. For example, ischemia/reperfusion or high workload challenge protocols can be adopted. The use of aortic banding or other models of cardiac pathology are apt as well. Regardless of the variants within the protocol, the functional and energetic significance of molecular modifications of transgenic mouse models can be adequately described, leading to new insights into the associated enzymatic and metabolic pathways. Therefore, 31P NMR spectroscopy in the isolated perfused heart is a valuable research technique in animal models of cardiovascular disease.

Assessment of Cardiac Function and Energetics in Isolated Mouse Hearts Using 31P NMR Spectroscopy

Langendorff-mode isolated heart perfusion, in conjunction with 31P NMR spectroscopy, combines the fields of biochemistry and physiology into one experiment. The protocol allows for the dynamic measurement of high energy phosphate content and turnover in the heart while concurrently monitoring physiologic function. When performed correctly, this is a valuable technique in the assessment of cardiac energetics.

Valutazione della funzione cardiaca e Energetica nel Cuori mouse isolato mediante 31 P spettroscopia NMR

Bioengineered mouse models have become powerful research tools in determining causal relationships between molecular alterations and models of ...

Ricerca

Medicina

NADH Fluorescence Imaging of Isolated Biventricular Working Rabbit Hearts

Since its inception by Langendorff1, the isolated perfused heart remains a prominent tool for studying cardiac physiology2. However, it is not well-suited for studies of cardiac metabolism, which require the heart to perform work within the context of physiologic preload and afterload pressures. Neely introduced modifications to the Langendorff technique to establish appropriate left ventricular (LV) preload and afterload pressures3. The model is known as the isolated LV working heart model and has been used extensively to study LV performance and metabolism4-6. This model, however, does not provide a properly loaded right ventricle (RV). Demmy et al. first reported a biventricular model as a modification of the LV working heart model7, 8. They found that stroke volume, cardiac output, and pressure development improved in hearts converted from working LV mode to biventricular working mode8. A properly loaded RV also diminishes abnormal pressure gradients across the septum to improve septal function. Biventricular working hearts have been shown to maintain aortic output, pulmonary flow, mean aortic pressure, heart rate, and myocardial ATP levels for up to 3 hours8.
When studying the metabolic effects of myocardial injury, such as ischemia, it is often necessary to identify the location of the affected tissue. This can be done by imaging the fluorescence of NADH (the reduced form of nicotinamide adenine dinucleotide)9-11, a coenzyme found in large quantities in the mitochondria. NADH fluorescence (fNADH) displays a near linearly inverse relationship with local oxygen concentration12 and provides a measure of mitochondrial redox state13. fNADH imaging during hypoxic and ischemic conditions has been used as a dye-free method to identify hypoxic regions14, 15 and to monitor the progression of hypoxic conditions over time10.
The objective of the method is to monitor the mitochondrial redox state of biventricular working hearts during protocols that alter the rate of myocyte metabolism or induce hypoxia or create a combination of the two. Hearts from New Zealand white rabbits were connected to a biventricular working heart system (Hugo Sachs Elektronik) and perfused with modified Krebs-Henseleit solution16 at 37 &deg;C. Aortic, LV, pulmonary artery, and left &amp; right atrial pressures were recorded. Electrical activity was measured using a monophasic action potential electrode. To image fNADH, light from a mercury lamp was filtered (350&plusmn;25 nm) and used to illuminate the epicardium. Emitted light was filtered (460&plusmn;20 nm) and imaged using a CCD camera. Changes in the epicardial fNADH of biventricular working hearts during different pacing rates are presented. The combination of the heart model and fNADH imaging provides a new and valuable experimental tool for studying acute cardiac pathologies within the context of realistic physiological conditions.

The objective is to monitor the mitochondrial redox state of isolated hearts within the context of physiologic preload and afterload pressures. A biventricular working rabbit heart model is presented. High spatiotemporal resolution fluorescence imaging of NADH is used to monitor the mitochondrial redox state of epicardial tissue.

NADH Imaging di fluorescenza biventricolare isolato lavoro Hearts Coniglio

Since its inception by Langendorff1, the isolated perfused heart remains a prominent tool for studying cardiac physiology2. However, it is not well-suited ...

Reduction in Left Ventricular Wall Stress and Improvement in Function in Failing Hearts using Algisyl-LVR

Injection of Algisyl-LVR, a treatment under clinical development, is intended to treat patients with dilated cardiomyopathy. This treatment was recently used for the first time in patients who had symptomatic heart failure. In all patients, cardiac function of the left ventricle (LV) improved significantly, as manifested by consistent reduction of the LV volume and wall stress. Here we describe this novel treatment procedure and the methods used to quantify its effects on LV wall stress and function.
Algisyl-LVR is a biopolymer gel consisting of Na+-Alginate and Ca2+-Alginate. The treatment procedure was carried out by mixing these two components and then combining them into one syringe for intramyocardial injections. This mixture was injected at 10 to 19 locations mid-way between the base and apex of the LV free wall in patients.
Magnetic resonance imaging (MRI), together with mathematical modeling, was used to quantify the effects of this treatment in patients before treatment and at various time points during recovery. The epicardial and endocardial surfaces were first digitized from the MR images to reconstruct the LV geometry at end-systole and at end-diastole. Left ventricular cavity volumes were then measured from these reconstructed surfaces.
Mathematical models of the LV were created from these MRI-reconstructed surfaces to calculate regional myofiber stress. Each LV model was constructed so that 1) it deforms according to a previously validated stress-strain relationship of the myocardium, and 2) the predicted LV cavity volume from these models matches the corresponding MRI-measured volume at end-diastole and end-systole. Diastolic filling was simulated by loading the LV endocardial surface with a prescribed end-diastolic pressure. Systolic contraction was simulated by concurrently loading the endocardial surface with a prescribed end-systolic pressure and adding active contraction in the myofiber direction. Regional myofiber stress at end-diastole and end-systole was computed from the deformed LV based on the stress-strain relationship.

This article describes procedures for implanting a novel hydrogel in failing hearts and quantifying its effect on left ventricular wall stress and function. These procedures have been successfully applied in dogs and humans.

Riduzione del ventricolo sinistro stress di parete e di miglioramento della funzione in mancanza di Cuori con Algisyl-LVR

Injection of  Algisyl-LVR, a treatment under clinical development, is intended to treat  patients with dilated cardiomyopathy. This treatment was recently ...

Method of Isolated Ex Vivo Lung Perfusion in a Rat Model: Lessons Learned from Developing a Rat EVLP Program

The number of acceptable donor lungs available for lung transplantation is severely limited due to poor quality. Ex-Vivo Lung Perfusion (EVLP) has allowed lung transplantation in humans to become more readily available by enabling the ability to assess organs and expand the donor pool. As this technology expands and improves, the ability to potentially evaluate and improve the quality of substandard lungs prior to transplant is a critical need. In order to more rigorously evaluate these approaches, a reproducible animal model needs to be established that would allow for testing of improved techniques and management of the donated lungs as well as to the lung-transplant recipient. In addition, an EVLP animal model of associated pathologies, e.g., ventilation induced lung injury (VILI), would provide a novel method to evaluate treatments for these pathologies. Here, we describe the development of a rat EVLP lung program and refinements to this method that allow for a reproducible model for future expansion. We also describe the application of this EVLP system to model VILI in rat lungs. The goal is to provide the research community with key information and &#8220;pearls of wisdom&#8221;/techniques that arose from trial and error and are critical to establishing an EVLP system that is robust and reproducible.

Method of Isolated Ex Vivo Lung Perfusion in a Rat Model: Lessons Learned from Developing a Rat EVLP Program

Ex-Vivo Lung Perfusion (EVLP) has allowed lung transplantation in humans to become more readily available by enabling the ability to assess organs and expand the donor pool. Here, we describe the development of a rat EVLP program and refinements that allow for a reproducible model for future expansion.

Metodo di isolato<em&gt; Ex Vivo</em&gt; Lung Perfusion in un modello di ratto: Lezioni apprese da Sviluppo di un programma EVLP Rat

The number of acceptable donor lungs available for lung transplantation is severely limited due to poor quality. Ex-Vivo Lung Perfusion (EVLP) has allowed ...

A Rat Model of Ventricular Fibrillation and Resuscitation by Conventional Closed-chest Technique

A rat model of electrically-induced ventricular fibrillation followed by cardiac resuscitation using a closed chest technique that incorporates the basic components of cardiopulmonary resuscitation in humans is herein described. The model was developed in 1988 and has been used in approximately 70 peer-reviewed publications examining a myriad of resuscitation aspects including its physiology and pathophysiology, determinants of resuscitability, pharmacologic interventions, and even the effects of cell therapies. The model featured in this presentation includes: (1) vascular catheterization to measure aortic and right atrial pressures, to measure cardiac output by thermodilution, and to electrically induce ventricular fibrillation; and (2) tracheal intubation for positive pressure ventilation with oxygen enriched gas and assessment of the end-tidal CO2. A typical sequence of intervention entails: (1) electrical induction of ventricular fibrillation, (2) chest compression using a mechanical piston device concomitantly with positive pressure ventilation delivering oxygen-enriched gas, (3) electrical shocks to terminate ventricular fibrillation and reestablish cardiac activity, (4) assessment of post-resuscitation hemodynamic and metabolic function, and (5) assessment of survival and recovery of organ function. A robust inventory of measurements is available that includes &#8211; but is not limited to &#8211; hemodynamic, metabolic, and tissue measurements. The model has been highly effective in developing new resuscitation concepts and examining novel therapeutic interventions before their testing in larger and translationally more relevant animal models of cardiac arrest and resuscitation.

This article describes a rat model of electrically-induced ventricular fibrillation and resuscitation by chest compression, ventilation, and delivery of electrical shocks that simulates an episode of sudden cardiac arrest and conventional cardiopulmonary resuscitation. The model enables gathering insights on the pathophysiology of cardiac arrest and exploration of new resuscitation strategies.

Un modello di ratto di fibrillazione ventricolare e Rianimazione dal convenzionale chiuso petto Tecnica

A rat model of electrically-induced ventricular fibrillation followed by cardiac resuscitation using a closed chest technique that incorporates the basic ...

Induction and Assessment of Ischemia-reperfusion Injury in Langendorff-perfused Rat Hearts

The biochemical events surrounding ischemia reperfusion injury in the acute setting are of great importance to furthering novel treatment options for myocardial infarction and cardiac complications of thoracic surgery. The ability of certain drugs to precondition the myocardium against ischemia reperfusion injury has led to multiple clinical trials, with little success. The isolated heart model allows acute observation of the functional effects of ischemia reperfusion injury in real time, including the effects of various pharmacological interventions administered at any time-point before or within the ischemia-reperfusion injury window. Since brief periods of ischemia can precondition the heart against ischemic injury, in situ aortic cannulation is performed to allow for functional assessment of non-preconditioned myocardium. A saline filled balloon is placed into the left ventricle to allow for real-time measurement of pressure generation. Ischemic injury is simulated by the cessation of perfusion buffer flow, followed by reperfusion. The duration of both ischemia and reperfusion can be modulated to examine biochemical events at any given time-point. Although the Langendorff isolated heart model does not allow for the consideration of systemic events affecting ischemia and reperfusion, it is an excellent model for the examination of acute functional and biochemical events within the window of ischemia reperfusion injury as well as the effect of pharmacological intervention on cardiac pre- and postconditioning. The goal of this protocol is to demonstrate how to perform in situ aortic cannulation and heart excision followed by ischemia/reperfusion injury in the Langendorff model.

The isolated rat heart is an enduring model for ischemia reperfusion injury. Here, we describe the process of harvesting the beating heart from a rat via in situ aortic cannulation, Langendorff perfusion of the heart, simulated ischemia-reperfusion injury, and infarct staining to confirm the extent of ischemic insult.

Induzione e valutazione di ischemia-riperfusione Injury in Langendorff-perfusi Hearts Rat

The biochemical events surrounding ischemia reperfusion injury in the acute setting are of great importance to furthering novel treatment options for ...

Surgical Placement of Catheters for Long-term Cardiovascular Exercise Testing in Swine

This protocol describes the surgical procedure to chronically instrument swine and the procedure to exercise swine on a motor-driven treadmill. Early cardiopulmonary dysfunction is difficult to diagnose, particularly in animal models, as cardiopulmonary function is often measured invasively, requiring anesthesia. As many anesthetic agents are cardiodepressive, subtle changes in cardiovascular function may be masked. In contrast, chronic instrumentation allows for measurement of cardiopulmonary function in the awake state, so that measurements can be obtained under quiet resting conditions, without the effects of anesthesia and acute surgical trauma. Furthermore, when animals are properly trained, measurements can also be obtained during graded treadmill exercise.
Flow probes are placed around the aorta or pulmonary artery for measurement of cardiac output and around the left anterior descending coronary artery for measurement of coronary blood flow. Fluid-filled catheters are implanted in the aorta, pulmonary artery, left atrium, left ventricle and right ventricle for pressure measurement and blood sampling. In addition, a 20 G&#160;catheter is positioned in the anterior interventricular vein to allow coronary venous blood sampling.
After a week of recovery, swine are placed on a motor-driven treadmill, the catheters are connected to pressure and flow meters, and swine are subjected to a five-stage progressive exercise protocol, with each stage lasting 3 min. Hemodynamic signals are continuously recorded and blood samples are taken during the last 30 sec of each exercise stage.
The major advantage of studying chronically instrumented animals is that it allows serial assessment of cardiopulmonary function, not only at rest but also during physical stress such as exercise. Moreover, cardiopulmonary function can be assessed repeatedly during disease development and during chronic treatment, thereby increasing statistical power and hence limiting the number of animals required for a study.

Here we present a protocol to assess cardiopulmonary function in awake swine, at rest and during graded treadmill exercise. Chronic instrumentation allows for repeated hemodynamic measurements uninfluenced by cardiodepressive anesthetic agents.

Posizionamento chirurgico di cateteri per durata Esercizio cardiovascolare test in Swine

This protocol describes the surgical procedure to chronically instrument swine and the procedure to exercise swine on a motor-driven treadmill. Early ...

Long-term Blood Pressure Measurement in Freely Moving Mice Using Telemetry

During the development of new vasoactive agents, arterial blood pressure monitoring is crucial for evaluating the efficacy of the new proposed drugs. Indeed, research focusing on the discovery of new potential therapeutic targets using genetically altered mice requires a reliable, long-term assessment of the systemic arterial pressure variation. Currently, the gold standard for obtaining long-term measurements of blood pressure in ambulatory mice uses implantable radio-transmitters, which require&#160;artery cannulation. This technique eliminates the need for tethering, restraining, or anesthetizing the animals which introduce stress and artifacts during data sampling. However, arterial blood pressure monitoring in mice via catheterization can be rather challenging due to the small size of the arteries. Here we present a step-by-step guide to illustrate the crucial key passages for a successful subcutaneous implantation of radio-transmitters and carotid artery cannulation in mice. We also include examples of long-term blood pressure activity taken from freely moving mice after a period of post-surgery recovery. Following this procedure will allow reliable direct blood pressure recordings from multiple animals simultaneously.

The goal of this protocol is to assess systemic blood pressure in conscious freely moving mice using implantable radio-telemetry devices.

Misurazione della pressione sanguigna a lungo termine in topi liberi di muoversi utilizzando la telemetria

During the development of new vasoactive agents, arterial blood pressure monitoring is crucial for evaluating the efficacy of the new proposed drugs. ...

The Inverted Heart Model for Interstitial Transudate Collection from the Isolated Rat Heart

The present protocol describes a unique approach that enables the collection of cardiac transudate (CT) from the isolated, saline-perfused rat heart. After isolation and retrograde perfusion of the heart according to the Langendorff technique, the heart is inverted into an upside-down position and is mechanically stabilized by a balloon catheter inserted into the left ventricle. Then, a thin latex cap &#8211; previously cast to match the average size of the rat heart &#8211; is placed over the epicardial surface. The outlet of the latex cap is connected to silicon tubing, with the distal opening 10 cm below the base level of the heart, creating slight suction. CT continuously produced on the epicardial surface is collected in ice-cooled vials for further analysis. The rate of CT formation ranged from 17 to 147 &#181;L/min (n = 14) in control and infarcted hearts, which represents 0.1-1% of the coronary venous effluent perfusate. Proteomic analysis and high performance liquid chromatography (HPLC) revealed that the collected CT contains a wide spectrum of proteins and purinergic metabolites.

This protocol describes a method to collect cardiac interstitial fluid from the isolated, perfused rat heart. To physically separate interstitial transudate from coronary venous effluent perfusate, the Langendorff perfused heart is inverted, and the transudate (interstitial fluid) formed on the cardiac surface is collected using a soft latex cap.

Il modello invertito del cuore per la raccolta di transudati interstiziali dal cuore isolato del ratto

The present protocol describes a unique approach that enables the collection of cardiac transudate (CT) from the isolated, saline-perfused rat heart. ...

Standardized Model of Ventricular Fibrillation and Advanced Cardiac Life Support in Swine

Cardiopulmonary resuscitation after cardiac arrest, independent of its origin, is a regularly encountered medical emergency in hospitals as well as preclinical settings. Prospective randomized trials in human subjects are difficult to design and ethically ambiguous, which results in a lack of evidence-based therapies. The model presented in this report represents one of the most common causes of cardiac arrests, ventricular fibrillation, in a standardized setting in a large animal model. This allows for reproducible observations and various therapeutic interventions under clinically accurate conditions, hence facilitating the generation of better evidence and eventually the potential for improved medical treatment.

Cardiopulmonary resuscitation and defibrillation are the only effective therapeutic options during cardiac arrest caused by ventricular fibrillation. This model presents a standardized regimen to induce, assess, and treat this physiological state in a porcine model, thus providing a clinical approach with various opportunities for data collection and analysis.

Modello standardizzato di fibrillazione ventricolare e supporto avanzato per la vita cardiaca in suina

Cardiopulmonary resuscitation after cardiac arrest, independent of its origin, is a regularly encountered medical emergency in hospitals as well as ...