Name: long-term blood pressure measurement in freely moving mice using telemetry
Uploaded: 2016-05-17T14:00:00.000+00:00
Duration: 7 min 54 s
Description: Watch this Scientific Journal Video about Long-term Blood Pressure Measurement in Freely Moving Mice Using Telemetry at JoVE.com

This work was supported by the National Institutes of Health (NIH/NHLBI) [Grant no. HL114869] and the support from UTHSC to SM.

Etica dichiarazione: Tutte le procedure origine animale di cui in questo video-articolo è stato esaminato e approvato dal Comitato di cura e l&#39;uso di animali (IACUC) presso l&#39;Università del Tennessee Health Science Center. Nota: utilizzare gli strumenti di microchirurgia sterili durante tutta la procedura chirurgica. Gli strumenti chirurgici possono essere sterilizzati utilizzando uno sterilizzatore infrarossa ad una temperatura ottimale di sterilizzazione 1.500 ° F (815,6 ° C). Telemetri possono essere riutilizzati, tuttavia, prima di inserirla nell&#39;animale assicurarsi di sterilizzare l&#39;intero trasmettitore secondo le istruzioni del produttore e che la punta del catetere è stata riempita con un gel speciale fornito dal produttore. 1. Gli animali sperimentali <ol><li> Ottenere l&#39;approvazione IACUC per tutti gli esperimenti che verranno eseguite. La consultazione con IACUC istituzionale è altamente raccomandato per quanto riguarda i requisiti per l&#39;uso di analgesici post-operatorio dopo questa procedura. </li><li> Tenere gli animali in ccamere limate controllata aventi una temperatura ambiente di 21 ° C, 60% umidità relativa, e un ciclo luce-buio di 12 ore con libero accesso a cibo e acqua. Nota: Perché il corpo del mouse deve accogliere la sonda telemetria (approssimativamente 1 cm di diametro x 2 cm di lunghezza), è preferibile utilizzare i topi che pesano 20 grammi. </li></ol> 2. Anestesia e preparazione Operativo <ol><li> Pesare il mouse usando una bilancia di precisione e registrare il suo peso. Assicurati di gestire l&#39;animale dolcemente e silenziosamente. </li><li> Posto l&#39;animale nella camera di induzione e chiuderlo. Impostare la velocità del flusso di ossigeno a 0,5 L / min e impostare la concentrazione isoflurano al 4-5%. </li><li> Quando il mouse perde conoscenza, metterlo su un piatto corpo riscaldamento mantenuto a 36-37 ° C. Mantenere l&#39;anestesia tramite nosecone con set isoflurano al 2% (tenere a portata di 0,5 l / min). </li><li> Preparare le regioni di funzionamento rimuovendo i capelli dalla parte posteriore del collo e tegli faccia ventrale del collo mediante l&#39;applicazione di crema depilatoria. </li><li> Trattare il sito di incisione con 3 applicazioni di lavaggio chirurgico (soluzione betadine) in alternanza con il 70% di alcol isopropilico. </li></ol> 3. Chirurgia <ol><li> Posizionare il mouse in posizione supina. Verificare la presenza di riflessi pizzicare il piede, e regolare l&#39;anestesia fino a quando non vi è alcuna risposta. Effettuare un approssimativamente 1 cm incisione mediana sotto il collo del mouse con un bisturi. Nel lato sinistro del taglio creare uno spazio sottocutaneo separando accuratamente la pelle dal tessuto connettivo sottostante. </li><li> Capovolgere il mouse, e utilizzare un bisturi per fare una incisione cutanea di circa 1,5 cm di lato dorsale sinistro dietro la scapola. Creare una tasca sottocutanea lungo il fianco dell&#39;animale sufficientemente grande per il dispositivo. Inserire il trasmettitore nella tasca. </li><li> Inserire un piccolo pinza emostatica nell&#39;incisione posteriore e manovrarlo sottocutanea verso la parte anterioreapertura del collo. Utilizzando la fascetta inserita-emostatico, prenda delicatamente un tubo in polietilene atossico (4 cm Lunghezza x 1 mm ID). <ol><li> Tirare il hemostat indietro attraverso il tunnel l&#39;incisione laterale nella parte posteriore finché il tubo sporge da entrambi addominale e dorsale incisione, rilasciare il tubo dal emostatico. Dalla parte posteriore, inserire il sensore catetere nel tubo per tunnel la punta del catetere di rilevamento della pressione attraverso il collo. Dalla anteriore del collo, tirare e rimuovere il tubo in polietilene e chiudere l&#39;incisione dorsale mediante clip metalliche. </li></ol></li><li> separare con cura le ghiandole mandibolari utilizzando applicatori di punta di cotone sterile e ritrarre la ghiandola mandibolare sinistra utilizzando un gancio elastico soggiorno. Utilizzando pinze curve punta fine, individuare la carotide lungo il lato sinistro della trachea. Mantenere il sito chirurgico sterile, mettendo e garantire un telino sterile. <ol><li> isolare con cura il recipiente dal tessuto circostante e delicatamente separare lanervo vago (colore biancastro) che si trova lungo l&#39;arteria carotide lontano dalla arteria. Fare attenzione a non tagliare o danneggiare il nervo o l&#39;arteria. </li></ol></li><li> Passare tre pezzi di non assorbibile 7-0 sutura sotto la sezione carotide isolato. Legare la sutura cranica per chiudere il flusso di sangue. Estrarre la sutura che è più vicino allo sterno per occludere temporaneamente il flusso di sangue dall&#39;aorta. </li><li> Fare un nodo sciolto utilizzando la sutura centrale. Questo verrà utilizzato per fissare il catetere nel vaso. Tagliare una piccola incisione nell&#39;arteria tra il cranio e le suture sternale con micro-forbici. </li><li> Afferra il catetere con una pinza speciale nave incannulamento, facendo attenzione a non comprimere il catetere per prevenire la perdita di gel dalla sonda. Delicatamente, afferrare l&#39;arteria con una pinzetta punta fine curvo pinze, recuperare il catetere, e inserirla nel vaso attraverso la piccola incisione. </li><li> Stringere il nodo di sutura intorno all&#39;arteria centrale e far avanzare con delicatezza il gattoheter. rilasciare delicatamente la sutura che è prossimale allo sterno e continuare ad avanzare il catetere verso l&#39;aorta trasversale. <ol><li> Osservare il contrassegno sul catetere che fornisce un indice approssimativa di quanto il catetere deve essere inserito. Una volta che il punto è raggiunto, delicatamente stringere sia inferiore e la sutura superiore intorno al catetere. Il catetere è fissato alla carotide dai nodi di sutura. </li></ol></li><li> Chiudere l&#39;incisione cutanea con non assorbibile 5-0 di sutura. Una volta chiusa, sigillare l&#39;incisione con tessuto adesivo. </li></ol> 4. chirurgico di recupero e BP Misure <ol><li> Monitorare animali da vicino per il ritorno di posture normali e comportamenti. Durante il periodo post-operatorio amministrare analgesia 24 ore come indicato da un veterinario del personale. </li><li> Una volta che gli animali hanno recuperato (5 - 7 giorni dopo l&#39;intervento), li alloggiare individualmente in una gabbia regolare del mouse posizionato sulla parte superiore della piastra ricevitore di telemetria. </li><li> Ruotare il TR impiantatoansmitters &quot;on&quot; e &quot;off&quot; utilizzando un dispositivo magnetico posizionati brevemente vicino all&#39;animale dall&#39;esterno della gabbia. </li></ol>

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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=Chronic+tempol+prevents+hypertension,+proteinuria,+and+poor+feto-placental+outcomes+in+BPH/5+mouse+model+of+preeclampsia.">Chronic tempol prevents hypertension, proteinuria, and poor feto-placental outcomes in BPH/5 mouse model of preeclampsia.</a> Hypertension. 51 (4), 1058-1065 (2008).</li><li>Lerman, L. O., Chade, A. R., Sica, V., Napoli, C. <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+hypertension:+an+overview.">Animal models of hypertension: an overview.</a> J Lab Clin Med. 146 (3), 160-173 (2005).</li><li>Johns, C., Gavras, I., Handy, D. E., Salomao, A., Gavras, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Models+of+experimental+hypertension+in+mice.">Models of experimental hypertension in mice.</a> Hypertension. 28 (6), 1064-1069 (1996).</li><li>Vatner, S. F., Braunwald, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiovascular+control+mechanisms+in+the+conscious+state.">Cardiovascular control mechanisms in the conscious state.</a> N Engl J Med. 293 (19), 970-976 (1975).</li><li>Zhao, 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=Arterial+Pressure+Monitoring+in+Mice.">Arterial Pressure Monitoring in Mice.</a> Curr Protoc Mouse Biol. 1, 105-122 (2011).</li><li>Whitesall, S. E., Hoff, J. B., Vollmer, A. P., D'Alecy, L. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+simultaneous+measurement+of+mouse+systolic+arterial+blood+pressure+by+radiotelemetry+and+tail-cuff+methods.">Comparison of simultaneous measurement of mouse systolic arterial blood pressure by radiotelemetry and tail-cuff methods.</a> Am J Physiol Heart Circ Physiol. 286 (6), H2408-H2415 (2004).</li><li>Kurtz, T. 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=Recommendations+for+blood+pressure+measurement+in+humans+and+experimental+animals.+Part+2:+Blood+pressure+measurement+in+experimental+animals:+a+statement+for+professionals+from+the+subcommittee+of+professional+and+public+education+of+the+American+Heart+Association+council+on+high+blood+pressure+research.">Recommendations for blood pressure measurement in humans and experimental animals. Part 2: Blood pressure measurement in experimental animals: a statement for professionals from the subcommittee of professional and public education of the American Heart Association council on high blood pressure research.</a> Hypertension. 45 (2), 299-310 (2005).</li><li>Kurtz, T. 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The authors have nothing to disclose.

Impiantabile radio-telemetria è migliorata significativamente negli ultimi dieci anni; dimensioni più piccole della sonda rende l&#39;impianto meno traumatica per l&#39;animale, la durata della batteria prolungata aiuta a ridurre i costi, e le frequenze telemetro indipendenti eliminare le interferenze tra i ricevitori. Telemetria è considerato il metodo allo stato dell&#39;arte per la raccolta di una vasta gamma di parametri fisiologici da animali liberi di muoversi senza artefatti dovuti all&#39;uso di contenzione, interazione umana, o anestesia che sono richiesti da altre tecniche di 8,9. Tuttavia, alcuni degli svantaggi della sua tecnica sono associati con costi iniziali di strumento e software. I trasmettitori sono fragili e suscettibili di danni, e la batteria non alla fine a corto di energia e devono essere sostituite. Anche se l&#39;azienda offre per ristrutturare quelle sonde danneggiate ad un costo inferiore, il costo può essere ancora proibitivo per alcuni laboratori.Inoltre, questa procedura può essere tecnicamente impegnativo e la pratica è necessaria per ottenere una misura affidabile BP. Infine, vi è una certa postoperatorio mortalità associate, che nelle nostre mani è di circa 5%. Questo può aumentare notevolmente se un trattamento specifico deve essere testato o se una manipolazione genetica compromette la salute mouse. I seguenti fattori critici sono essenziali per il buon esito della procedura: mantenere l&#39;idratazione dei tessuti con soluzione salina sterile durante tutta la procedura. Maneggiare sempre il trasmettitore con grande cura; evitare tenendolo per il sensore di pressione in quanto ciò potrebbe causare il gel di fuoriuscire o danneggiare il trasmettitore. Quando si inserisce il catetere, legare la sutura centrale con un doppio nodo, come in caso contrario si comporterà il catetere esce dalla nave. La lunghezza del catetere richiesta che deve essere inserito nella carotide può variare a seconda del ceppo mouse e peso utilizzato in tale particostudio lar. Pertanto, si raccomanda vivamente di eseguire qualche esperimento preliminare per determinare quanto in profondità il catetere deve essere inserita per evitare l&#39;occlusione dell&#39;aorta. Infine, monitorare l&#39;animale quotidiana e assicurarsi che la pelle sopra il trasmettitore non è allungata o necrotico. Se si verifica necrosi estese o infezione, eutanasia gli animali in base alla politica istituzionale.

L&#39;ipertensione è uno dei principali fattori di rischio per le malattie cardiovascolari, senza dubbio si tratta di un grave problema di salute pubblica sia nei paesi sviluppati e in via di sviluppo 1. Diversi modelli animali di ipertensione sperimentale sono stati sviluppati per imitare risposte ipertensive come quelle osservate nell&#39;uomo 2. Tra gli altri, il mouse ambulatoriale rappresenta un ottimo modello per studiare la genesi e la progressione dell&#39;ipertensione permettendo nell&#39;analisi vivo delle conseguenze dell&#39;esposizione cronica a ipertensione. La pressione sanguigna (BP) monitoraggio nei topi ha aiutato i ricercatori a svelare diversi meccanismi coinvolti nella fisiologia e fisiopatologia delle malattie come l&#39;ipertensione e insufficienza cardiaca 3, 4. Infatti, la manipolazione del genoma del topo permesso generazione di transgenici o modelli gene targeting adatto per studiare l&#39;ipertensione 5, 6. Tuttavia, anche la manipolazione delicatadi topi consapevole induce emozioni che possono potenzialmente introdurre artefatti durante l&#39;acquisizione dei dati, mentre l&#39;uso di sedazione o tranquillanti profondamente influenzare la pressione sanguigna 7. Questi aspetti sono particolarmente importanti e devono essere presi in considerazione quando si tenta di monitoraggio a lungo termine BP. Ci sono diversi modi per registrare BP nei topi, e un confronto tra le tecniche più comuni attualmente disponibili sono stati discussi altrove 8, 9. Tuttavia, le raccomandazioni AHA per la misurazione BP concluso che la misurazione endoarteriosa di BP sono generalmente preferiti per la loro capacità di misurare direttamente BP per un periodo prolungato di tempo 10. Radio-telemetria accoppiato con la misura diretta della pressione arteriosa è il metodo di state-of-the-art per il monitoraggio delle funzioni fisiologiche in sveglio e liberi di muoversi animali da laboratorio, riducendo al minimo lo stress e manufatti per l&#39;ambiente associati 9, 11.Radio-telemetria offre la possibilità di raccogliere automaticamente la pressione arteriosa, frequenza cardiaca, la temperatura corporea e l&#39;attività degli animali provenienti da animali coscienti multipli. Anche se questa metodologia sta diventando molto popolare in molti laboratori, radio-telemetria impianto in topi può essere tecnicamente impegnativo. Qui mostriamo un protocollo passo-passo che illustra come impiantare un trasduttore di pressione nei topi. La tecnica prevede l&#39;inserimento sottocutaneo della sonda nel corpo del mouse, incanalare il catetere al collo e in avanti vicino all&#39;arco aortico attraverso l&#39;arteria carotide sinistra. dati in remoto catturati vengono trasmesse in diretta sul monitor del computer. I dati sono memorizzati anche per l&#39;analisi &quot;off-line&quot;.

<table><tbody><tr><td>Small animal anesthesia system</td><td>Kent Scientific Corp, Torrington, Connecticut, USA</td><td></td><td>low-flow small animal anesthesia system</td></tr><tr><td>Pad warmer and mouse termometer</td><td>Kent Scientific Corp, Torrington, Connecticut, USA</td><td></td><td>allows monitoring body temperature, and homeothermic control in small animals</td></tr><tr><td>Binocular Microscope</td><td>Kent Scientific Corp, Torrington, Connecticut, USA</td><td>KSCXTS-1121</td><td>binocular body with boom stand pole and top LED</td></tr><tr><td>Hemostat Forceps</td><td>Kent Scientific Corp, Torrington, Connecticut, USA</td><td>INS750451</td><td>used to clamp blood vessels or tag sutures</td></tr><tr><td>Small metal Clips, 7 mm, Stainless Steel</td><td>Kent Scientific Corp, Torrington, Connecticut, USA</td><td>INS750344</td><td>used for skin closure</td></tr><tr><td>Betadine solution</td><td>Purdue Products L.P., Stamford, CT, USA</td><td>NDC-67618-150-01</td><td>10% povidone iodine topical solution</td></tr><tr><td>Normal saline solution</td><td>Abott Laboratories</td><td>04930-04-10</td><td>needed for preventing tissue from drying.</td></tr><tr><td>Nair (Hair remover lotion)</td><td></td><td></td><td>needed for fur removal from the site of incision/surgery</td></tr><tr><td>Braide silk suture</td><td>Teleflex Medical OEM, Coventry, Connecticut, USA</td><td></td><td>Size 5.0, 6.0, 7.0</td></tr><tr><td>Ethanol</td><td></td><td>2716</td><td>70% ethanol for disinfection</td></tr><tr><td>Spring scissors&amp;nbsp;</td><td>Fine Science Tool</td><td>15000-10</td><td>for minor dissection</td></tr><tr><td>Scissors (angled to side)</td><td>Fine Science Tool</td><td>14063-011</td><td>No. 3 handle</td></tr><tr><td>Scalpel blade</td><td></td><td>2976-0</td><td>No. 10</td></tr><tr><td>Forceps (curved)</td><td>Fine Science Tool</td><td>11150-10</td><td>for holding tissue</td></tr><tr><td>Forceps (straight)</td><td>Fine Science Tool</td><td>11151-10</td><td>for holding tissue</td></tr><tr><td>Needle holder&amp;nbsp;</td><td>Fine Science Tool</td><td>12002-12</td><td>for suturing</td></tr><tr><td>Fine needle nose Forceps</td><td>Fine Science Tool</td><td></td><td></td></tr><tr><td>Isoflurane</td><td>Henry Schein&amp;nbsp;Animal Health, Melville, New York, USA</td><td></td><td>a general inhalation anesthetic agent</td></tr><tr><td>Sterilizer</td><td>Benchmark Scientific, 116 Corporate Blvd, South Plainfield, NJ, USA</td><td>B1000</td><td>sterilize surgical tools&amp;nbsp;in 5-10 seconds using infrared heating</td></tr><tr><td>Gauze Pads</td><td>Johnson &amp;amp; Johnson, New Brunswick, NJ, USA</td><td>JJ8513</td><td>to use for wound cleaning, prepping, scrubbing or dressing</td></tr><tr><td>Telemetry Device</td><td>Data Sciences International, St. Paul, MN, USA</td><td>DSI-PA-C10</td><td>to record blood pressure in freely moving mice</td></tr><tr><td>Telemetry receiver system&amp;nbsp; coumpled with a PC</td><td>Data Sciences International, St. Paul, MN, USA</td><td></td><td></td></tr><tr><td>Tubing</td><td>Instech Laboratories, Plymouth Meeting, PA USA</td><td>BTPE-90</td><td></td></tr><tr><td>Vessel Cannulation Forceps, 13 cm, 0.5 mm OD</td><td>World Precision Instruments</td><td>503374</td><td>special vessel cannulation forceps</td></tr><tr><td>Tissue adhesive</td><td>3M Animal Care Products, St. Paul, MN, USA</td><td>NAC No.:&amp;nbsp;11380041</td><td>use to close minor wounds, often eliminating the need for sutures and/or bandages</td></tr><tr><td>Weighing scale&amp;nbsp;</td><td></td><td>BB300</td><td>precision analytical laboratory balance</td></tr></tbody></table>

long-term blood pressure measurement in freely moving mice using telemetry

Durante lo sviluppo di nuovi agenti vasoattivi, monitoraggio della pressione arteriosa è cruciale per valutare l&#39;efficacia di nuovi farmaci proposti. In effetti, la ricerca incentrata sulla scoperta di nuovi potenziali bersagli terapeutici utilizzando topi geneticamente modificati richiede un giudizio affidabile a lungo termine della variazione di pressione arteriosa sistemica. Attualmente, il gold standard per l&#39;ottenimento di misure a lungo termine della pressione sanguigna nei topi ambulatoriali utilizza impiantabili di radio-trasmettitori, che richiedono incannulamento arteria. Questa tecnica elimina la necessità di legare, immobilizzare o anestetizzare gli animali che introducono stress e manufatti durante il campionamento dei dati. Tuttavia, il monitoraggio della pressione arteriosa nei topi tramite cateterizzazione può essere piuttosto difficile a causa delle ridotte dimensioni delle arterie. Qui vi presentiamo una guida passo-passo per illustrare i passaggi chiave cruciali per un impianto sottocutaneo di successo di radio-trasmettitori e carotide cannulation nei topi. Abbiamo anche esempi di attività di pressione sanguigna a lungo termine presi dai topi liberi di muoversi dopo un periodo di recupero post-operatorio. A seguito di questa procedura consentirà registrazioni della pressione sanguigna diretta affidabili da più animali contemporaneamente.

I dati possono essere acquisiti in remoto da un ricevitore; tracce vengono visualizzate su uno schermo di computer per il controllo di qualità (Figura 1a). Dettagli come ID animale, pressione diastolica e pressione arteriosa sistolica sono indicate anche (Figura 1b). Arteriosa BP può essere registrata in continuo (24/7), o per brevi intervalli programmati (ad esempio, 60 sec acquisizione ogni ora). I dati possono essere memorizzati automaticamente in un disco rigido per una successiva analisi. Mediati dati BP da una registrazione continua di 3 giorni sono mostrati (figura 2), è possibile apprezzare la variazione del ritmo circadiano tra il ciclo di luce e buio. Media della frequenza variazione di pressione e il cuore sono stati calcolati e rilevata in tempo. <img alt="Figura 1" src="/files/ftp_upload/53991/53991fig1.jpg" /> Figura 1. Tracciati pressione sanguigna tipici </strong&gt; di 4 topi diversi impiantati con telemetrica dispositivo. Tracciati (A) che mostrano in tempo reale i cambiamenti della pressione arteriosa (mmHg) nel corso di un intervallo di 5 min. I dati sono acquisiti contemporaneamente da quattro topi adulti 5 giorni dopo l&#39;impianto. (B) Tracciare a più alta risoluzione temporale estratto da A, è possibile apprezzare diastolica pressione e valori sistolici, BP durata del ciclo, e la frequenza cardiaca. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/53991/53991fig1large.jpg" target="_blank">Si prega di cliccare qui per vedere una versione più grande di questa figura.</a> <img alt="figura 2" src="/files/ftp_upload/53991/53991fig2.jpg" /> Pressione Figura 2. A lungo termine arteriosa del sangue mostra ritmo circadiano Variation. Dati relativi alla pressione mediate che illustrano i valori di (A) pressione sistolica (SP), (B) pressione diastolica (DP), (C) della pressione arteriosa media (MAP), e (D) RA cuoreTE espresso in battiti / min. I dati sono stati estratti da registrazioni continue prese durante il giorno (ciclo luce, L) o di notte (buio ciclo, D). Registrazione iniziato 7 giorni dopo l&#39;intervento chirurgico. Tutti i dati sono espressi come media ± SEM (n = 4 topi). <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/53991/53991fig2large.jpg" target="_blank">Clicca qui per vedere una versione più grande di questa figura.</a>

Watch this Scientific Journal Video about Long-term Blood Pressure Measurement in Freely Moving Mice Using Telemetry at JoVE.com

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

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

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

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

long-term-blood-pressure-measurement-freely-moving-mice-using

Nanyang Technological University

Research

JoVE Journal

Medicine

18.6K Views.  University of Tennessee Health Sciences Center. The goal of this protocol is to assess systemic blood pressure in conscious freely moving mice using implantable radio-telemetry devices.

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

Implantation of Radiotelemetry Transmitters Yielding Data on ECG, Heart Rate, Core Body Temperature and Activity in Free-moving Laboratory Mice

The laboratory mouse is the animal species of choice for most biomedical research, in both the academic sphere and the pharmaceutical industry. Mice are a manageable size and relatively easy to house. These factors, together with the availability of a wealth of spontaneous and experimentally induced mutants, make laboratory mice ideally suited to a wide variety of research areas.
In cardiovascular, pharmacological and toxicological research, accurate measurement of parameters relating to the circulatory system of laboratory animals is often required. Determination of heart rate, heart rate variability, and duration of PQ and QT intervals are based on electrocardiogram (ECG) recordings. However, obtaining reliable ECG curves as well as physiological data such as core body temperature in mice can be difficult using conventional measurement techniques, which require connecting sensors and lead wires to a restrained, tethered, or even anaesthetized animal. Data obtained in this fashion must be interpreted with caution, as it is well known that restraining and anesthesia can have a major artifactual influence on physiological parameters1, 2.
Radiotelemetry enables data to be collected from conscious and untethered animals. Measurements can be conducted even in freely moving animals, and without requiring the investigator to be in the proximity of the animal. Thus, known sources of artifacts are avoided, and accurate and reliable measurements are assured. This methodology also reduces interanimal variability, thus reducing the number of animals used, rendering this technology the most humane method of monitoring physiological parameters in laboratory animals3, 4. Constant advancements in data acquisition technology and implant miniaturization mean that it is now possible to record physiological parameters and locomotor activity continuously and in realtime over longer periods such as hours, days or even weeks3, 5.
Here, we describe a surgical technique for implantation of a commercially available telemetry transmitter used for continuous measurements of core body temperature, locomotor activity and biopotential (i.e. onelead ECG), from which heart rate, heart rate variability, and PQ and QT intervals can be established in freeroaming, untethered mice. We also present pre-operative procedures and protocols for post-operative intensive care and pain treatment that improve recovery, well-being and survival rates in implanted mice5, 6.

A surgical technique for implantation of commercially available telemetry transmitters used for continuous measurement of biopotential (one-lead ECG), heart rate, core body temperature and locomotor activity in freely moving mice is shown. Recommendations and protocols for post-operative care and pain relief, improving recovery, well being and survival rate are also presented.

L&#39;impianto di trasmettitori Radiotelemetry Cedendo dati su ECG, frequenza cardiaca, temperatura corporea e attività di movimento libero topi di laboratorio

The laboratory mouse is the animal species of choice for most biomedical research, in both the academic sphere and the pharmaceutical industry. Mice are a ...

Ricerca

Medicina

Measuring Blood Pressure in Mice using Volume Pressure Recording, a Tail-cuff Method

The CODA 8-Channel High Throughput Non-Invasive Blood Pressure system measures the blood pressure in up to 8 mice or rats simultaneously. The CODA tail-cuff system uses Volume Pressure Recording (VPR) to measure the blood pressure by determining the tail blood volume. A specially designed differential pressure transducer and an occlusion tail-cuff measure the total blood volume in the tail without the need to obtain the individual pulse signal. Special attention is afforded to the length of the occlusion cuff in order to derive the most accurate blood pressure readings. VPR can easily obtain readings on dark-skinned rodents, such as C57BL6 mice and is MRI compatible. The CODA system provides you with measurements of six (6) different blood pressure parameters; systolic and diastolic blood pressure, heart rate, mean blood pressure, tail blood flow, and tail blood volume. Measurements can be made on either awake or anesthetized mice or rats. The CODA system includes a controller, laptop computer, software, cuffs, animal holders, infrared warming pads, and an infrared thermometer. There are seven different holder sizes for mice as small as 8 grams to rats as large as 900 grams.

The CODA 8-Channel High Throughput Non-Invasive Blood Pressure system measures the blood pressure in up to 8 mice or rats simultaneously. This tail-cuff system uses Volume Pressure Recording (VPR) to measure the blood pressure by determining the tail blood volume.

Misurazione della pressione sanguigna nei topi mediante pressione del volume di registrazione, una coda-bracciale Metodo

The CODA 8-Channel High Throughput Non-Invasive Blood Pressure system measures the blood pressure in up to 8 mice or rats simultaneously. The CODA ...

Biologia

Monitoring of Systemic and Hepatic Hemodynamic Parameters in Mice

The use of mouse models in experimental research is of enormous importance for the study of hepatic physiology and pathophysiological disturbances. However, due to the small size of the mouse, technical details of the intraoperative monitoring procedure suitable for the mouse were rarely described. Previously we have reported a monitoring procedure to obtain hemodynamic parameters for rats. Now, we adapted the procedure to acquire systemic and hepatic hemodynamic parameters in mice, a species ten-fold smaller than rats. This film demonstrates the instrumentation of the animals as well as the data acquisition process needed to assess systemic and hepatic hemodynamics in mice. Vital parameters, including body temperature, respiratory&#160;rate&#160;and heart&#160;rate were recorded throughout the whole procedure. Systemic hemodynamic parameters consist of carotid artery pressure (CAP) and central venous pressure (CVP). Hepatic perfusion parameters include portal vein pressure (PVP), portal flow rate as well as the flow rate of the common hepatic artery (table 1). Instrumentation and data acquisition to record the normal values was completed within 1.5 h. Systemic and hepatic hemodynamic parameters remained within normal ranges during this procedure.
This procedure is challenging but feasible. We have already applied this procedure to assess hepatic hemodynamics in normal mice as well as during 70% partial hepatectomy and in liver lobe clamping experiments. Mean PVP after resection (n= 20), was 11.41&#177;2.94 cmH2O which was significantly higher (P&#60;0.05) than before resection (6.87&#177;2.39 cmH2O). The results of liver lobe clamping experiment indicated that this monitoring procedure is sensitive and suitable for detecting small changes in portal pressure and portal flow rate. In conclusion, this procedure is reliable in the hands of an experienced micro-surgeon but should be limited to experiments where mice are absolutely needed.

This film demonstrates how to acquire systemic and hepatic hemodynamics in mice. The whole monitoring includes acquisition of vital parameters, systemic blood pressure, central venous pressure, common hepatic artery flow rate, and portal vein pressure as well as the portal flow rate in mice.

Monitoraggio della sistemici e epatica parametri emodinamici nei topi

The use of mouse models in experimental research is of enormous importance for the study of hepatic physiology and pathophysiological disturbances. ...

Intrauterine Telemetry to Measure Mouse Contractile Pressure In Vivo

A complex integration of molecular and electrical signals is needed to transform a quiescent uterus into a contractile organ at the end of pregnancy. Despite the discovery of key regulators of uterine contractility, this process is still not fully understood. Transgenic mice provide an ideal model in which to study parturition. Previously, the only method to study uterine contractility in the mouse was ex vivo isometric tension recordings, which are suboptimal for several reasons. The uterus must be removed from its physiological environment, a limited time course of investigation is possible, and the mice must be sacrificed. The recent development of radiometric telemetry has allowed for longitudinal, real-time measurements of in vivo intrauterine pressure in mice. Here, the implantation of an intrauterine telemeter to measure pressure changes in the mouse uterus from mid-pregnancy until delivery is described. By comparing differences in pressures between wild type and transgenic mice, the physiological impact of a gene of interest can be elucidated. This technique should expedite the development of therapeutics used to treat myometrial disorders during pregnancy, including preterm labor.

Intrauterine Telemetry to Measure Mouse Contractile Pressure In Vivo

This manuscript provides a protocol for implanting telemeters in the mouse for the purpose of measuring intrauterine pressures during pregnancy.

Telemetria intrauterina misurare mouse contrattile Pressione<em&gt; In Vivo</em

A complex integration of molecular and electrical signals is needed to transform a quiescent uterus into a contractile organ at the end of pregnancy. ...

Novel Approach for Simultaneous Recording of Renal Sympathetic Nerve Activity and Blood Pressure with Intravenous Infusion in Conscious, Unrestrained Mice.

Renal sympathetic nerves contribute significantly to both physiological and pathophysiological phenomena. Evaluating renal sympathetic nerve activity (RSNA) is of great interest in many areas of research such as chronic kidney disease, hypertension, heart failure, diabetes and obesity. Unequivocal assessment of the role of the sympathetic nervous system is thus imperative for proper interpretation of experimental results and understanding of disease processes. RSNA has been traditionally measured in anesthetized rodents, including mice. However, mice usually exhibit very low systemic blood pressure and hemodynamic instability for several hours during anesthesia and surgery. Meaningful interpretation of RSNA is confounded by this non-physiological state, given the intimate relationship between sympathetic nervous tone and cardiovascular status. To address this limitation of traditional approaches, we developed a new method for measuring RSNA in conscious, freely-moving mice. Mice were chronically instrumented with radio-telemeters for continuous monitoring of blood pressure as well as a jugular venous infusion catheter and custom-designed bipolar electrode for direct recording of RSNA. Following a 48-72 hour recovery period, survival rate was 100% and all mice behaved normally. At this time-point, RSNA was successfully recorded in 80% of mice, with viable signals acquired up to 4 and 5 days post-surgery in 70% and 50% of mice, respectively. Physiological blood pressures were recorded in all mice (116&plusmn;2 mmHg; n=10). Recorded RSNA increased with eating and grooming, as well-established in the literature. Furthermore, RSNA was validated by ganglionic blockade and modulation of blood pressure with pharmacological agents. Herein, an effective and manageable method for clear recording of RSNA in conscious, freely-moving mice is described.

Anesthetized mice exhibit non-physiological systemic blood pressure, which precludes meaningful assessment of autonomic tone given the intimate relationship between blood pressure and the autonomic nervous system. Thus, a novel method to simultaneously record renal sympathetic nerve activity and blood pressure with intravenous infusion in conscious mice is outlined.

Nuovo approccio per la registrazione simultanea di attività simpatica renale del nervo e pressione del sangue con l'infusione endovenosa in consapevole, topi sfrenati.

Renal sympathetic nerves contribute significantly to both physiological and pathophysiological phenomena. Evaluating renal sympathetic nerve activity ...

Simultaneous Electrocardiography Recording and Invasive Blood Pressure Measurement in Rats

For studies related to cardiovascular physiology or pathophysiology, blood pressure (BP) and electrocardiography are basic observational parameters. Research focusing on cardiovascular disease models, potential cardiovascular therapeutic targets or pharmaceutical agents requires assessment of systemic arterial pressure and heart rhythm changes. In situations where radio telemetry systems are not available or affordable, the technique of femoral artery cannulation is an alternative way to obtain intra-arterial pressure waveform recordings and systemic BP measurements. This technique is economical and can be performed with standard equipment in animal facilities. However, invasive arterial pressure recording requires cannulation of small arteries, which can be a challenging surgical skill. Here, we present step-by-step protocols for femoral artery cannulation procedures. Key procedures include the calibration of the data acquisition system, tissue dissection and femoral artery cannulation, and setup of the arterial cannulation system for pressure recording. Surface electrocardiography recording procedures are also included. We also present examples of BP recordings from normotensive and hypertensive rats. This protocol allows reliable direct recordings of systemic BP with simultaneous electrocardiography.

Here, we describe a setup for simultaneous recording of electrocardiography and intra-arterial blood pressure (BP) in experimental rats, which can be done with standard equipment in animal facilities and can be applied to physiological or pharmacological studies to investigate pathogenic or therapeutic mechanisms in cardiovascular medicine.

Elettrocardiografia simultanea registrazione e invasiva sangue pressione misura in ratti

For studies related to cardiovascular physiology or pathophysiology, blood pressure (BP) and electrocardiography are basic observational parameters. ...

Implantation of Combined Telemetric ECG and Blood Pressure Transmitters to Determine Spontaneous Baroreflex Sensitivity in Conscious Mice

Blood pressure (BP) and heart rate (HR) are both controlled by the autonomic nervous system (ANS) and are closely intertwined due to reflex mechanisms. The baroreflex is a key homeostatic mechanism to counteract acute, short-term changes in arterial BP and to maintain BP in a relatively narrow physiological range. BP is sensed by baroreceptors located in the aortic arch and carotid sinus. When BP changes, signals are transmitted to the central nervous system and are then communicated to the parasympathetic and sympathetic branches of the autonomic nervous system to adjust HR. A rise in BP causes a reflex decrease in HR, a drop in BP causes a reflex increase in HR.
Baroreflex sensitivity (BRS) is the quantitative relationship between changes in arterial BP and corresponding changes in HR. Cardiovascular diseases are often associated with impaired baroreflex function. In various studies reduced BRS has been reported in e.g., heart failure, myocardial infarction, or coronary artery disease. 
Determination of BRS requires information from both BP and HR, which can be recorded simultaneously using telemetric devices. The surgical procedure is described beginning with the insertion of the pressure sensor into the left carotid artery and positioning of its tip in the aortic arch to monitor arterial pressure followed by the subcutaneous placement of the transmitter and ECG electrodes. We also describe postoperative intensive care and analgesic management. After a two-week period of post-surgery recovery long-term ECG and BP recordings are performed in conscious and unrestrained mice. Finally, we include examples of high-quality recordings and the analysis of spontaneous baroreceptor sensitivity using the sequence method.

The baroreflex is a heart-rate regulation mechanism by the autonomic nervous system in response to blood-pressure changes. We describe a surgical technique to implant telemetry transmitters for continuous and simultaneous measurement of electrocardiogram and blood pressure in mice. This can determine spontaneous baroreflex sensitivity, an important prognostic marker for cardiovascular disease.

Impianto combinato di ECG telemetrico e trasmettitori di pressione sanguigna per determinare la sensibilità baroriflessa spontanea in topi coscienti

Blood pressure (BP) and heart rate (HR) are both controlled by the autonomic nervous system (ANS) and are closely intertwined due to reflex mechanisms. ...

Long-Term Continuous Measurement of Renal Blood Flow in Conscious Rats

The kidneys play a crucial role in maintaining the homeostasis of body fluids. The regulation of renal blood flow (RBF) is essential to the vital functions of filtration and metabolism in kidney function. Many acute studies have been carried out in anesthetized animals to measure RBF under various conditions to determine mechanisms responsible for the regulation of kidney perfusion. However, for technical reasons, it has not been possible to measure RBF continuously (24 h/day) in unrestrained unanesthetized rats over prolonged periods. These methods allow the continuous determination of RBF over many weeks while also simultaneously recording blood pressure (BP) with implanted catheters (fluid-filled or by telemetry). RBF monitoring is carried out with rats placed in a circular servo-controlled rat cage that enables the unrestrained movement of the rat throughout the study. At the same time, the tangling of cables from the flow probe and arterial catheters is prevented. Rats are first instrumented with an ultrasonic flow probe placement on the left renal artery and an arterial catheter implanted in the right femoral artery. These are routed subcutaneously to the nape of the neck, and connected to the flowmeter and pressure transducer, respectively, to measure RBF and BP. Following surgical implantation, rats are immediately placed in the cage to recover for at least one week and stabilize the ultrasonic probe recordings. Urine collection is also feasible in this system. The surgical and post-surgical procedures for continuous monitoring are demonstrated in this protocol.

The present protocol describes a long-term continuous measurement of renal blood flow in conscious rats and simultaneously recording blood pressure with implanted catheters (fluid-filled or by telemetry).

Misurazione continua a lungo termine del flusso sanguigno renale nei ratti coscienti

The kidneys play a crucial role in maintaining the homeostasis of body fluids. The regulation of renal blood flow (RBF) is essential to the vital ...

Multiple Intravenous Bolus Dosing and Invasive Hemodynamic Assessment in a Hypoxia-Induced Mouse Pulmonary Artery Hypertension Model

Pulmonary arterial hypertension (PAH) is a progressive life-threatening disease, primarily affecting small pulmonary arterioles of the lung. Currently, there is no cure for PAH. It is important to discover new compounds that can be used to treat PAH. The mouse hypoxia-induced PAH model is a widely used model for PAH research. This model recapitulates human clinical manifestations of PAH Group 3 disease and is an important research tool to evaluate the effectiveness of new experimental therapies for PAH. Research using this model often requires the administration of compounds in mice. For a compound that needs to be given directly into the bloodstream, optimizing intravenous (IV) administration is a key part of the experimental procedures. Ideally, the IV injection system should permit multiple injections over a set time course. Although the mouse hypoxia-induced PAH model is very popular in many laboratories, it is technically challenging to perform multiple IV bolus dosing and invasive hemodynamic assessment in this model. In this protocol, we present step-by-step instructions on how to carry out multiple IV bolus dosing via mouse jugular vein and perform arterial and right ventricle catheterization for hemodynamic assessment in mouse hypoxia-induced PAH model.

This protocol provides a step-by-step procedure for executing multiple intravenous bolus dose administration and invasive hemodynamic monitoring in mice. Investigators can use this protocol for future therapeutic compound screening for pulmonary artery hypertension.

Dosaggio multiplo in bolo endovenoso e valutazione emodinamica invasiva in un modello murino di ipertensione arteriosa polmonare indotta da ipossia

Pulmonary arterial hypertension (PAH) is a progressive life-threatening disease, primarily affecting small pulmonary arterioles of the lung. Currently, ...

Simple Continuous Glucose Monitoring in Freely Moving Mice

Mice are a common model organism used to study metabolic diseases such as diabetes mellitus. Glucose levels are typically measured by tail-bleeding, which requires handling the mice, causes stress, and does not provide data on freely behaving mice during the dark cycle. State-of-the-art continuous glucose measurement in mice requires inserting a probe into the aortic arch of the mouse, as well as a specialized telemetry system. This challenging and expensive method has not been adopted by most labs. Here, we present a simple protocol involving the utilization of commercially available continuous glucose monitors used by millions of patients to measure glucose continuously in mice as a part of basic research. The glucose-sensing probe is inserted into the subcutaneous space in the back of the mouse through a small incision to the skin and is held in place tightly using a couple of sutures. The device is sutured to the mouse skin to ensure it remains in place. The device can measure glucose levels for up to 2 weeks and sends the data to a nearby receiver without any need to handle the mice. Scripts for the basic data analysis of glucose levels recorded are provided. This method, from surgery to computational analysis, is cost-effective and potentially very useful in metabolic research.

Here, we describe a simple method to implant a commercial continuous glucose monitor designed for patients onto mice and provide the scripts to analyze the results.

Semplice monitoraggio continuo del glucosio in topi che si muovono liberamente

Mice are a common model organism used to study metabolic diseases such as diabetes mellitus. Glucose levels are typically measured by tail-bleeding, which ...

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

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L'impianto di trasmettitori Radiotelemetry Cedendo dati su ECG, frequenza cardiaca, temperatura corporea e attività di movimento libero topi di laboratorio