The study was supported by the Swiss National Foundation [SNF 310030-149986 to MNG], the University of Fribourg, and Fribourg Hospital.

Tutti gli animali hanno ricevuto cura umana nel rispetto della Convenzione europea sulla cura degli animali. Le procedure chirurgiche sono state eseguite in conformità con la legge svizzera sulla protezione degli animali dopo aver ottenuto l&#39;autorizzazione del veterinario di Stato, Friborgo, approvato dal veterinario, la Svizzera federale. Raccolta 1. Cuore NOTA: Tutti gli interventi chirurgici sono stati eseguiti in anestesia isoflurano. Gli sforzi sono stati fatti per ridurre la sofferenza degli animali. In particolare, tutti gli animali hanno ricevuto una iniezione sottocutanea di 0,1 mg / kg buprenorfina pre-anestesia. Il protocollo chirurgico per induzione di infarto miocardico è stato precedentemente descritto altrove 13. <ol><li> Eseguire una sternotomia su un animale myocardially infartuato in anestesia (animale intubato, 2,5% isoflurano, anestesia corretta confermati dalla zampa pizzico reflex). <ol><li> Aprire l&#39;animale tagliando la pelle e poi i muscolicon le forbici chirurgiche. Tagliare le costole a sinistra ea destra, e quindi rimuovere il petto. </li><li> Rimuovere le adesioni rimanenti dopo l&#39;intervento chirurgico precedente (LAD legatura). Tagliare l&#39;aorta e rimuovere il cuore. Mettere il tessuto in 1 M KCl (in PBS), e poi lavare con PBS. </li></ol></li></ol> 2. Preparazione del tessuto <ol><li> Mettere il cuore infartuato longitudinalmente in una matrice acrilica cuore di ratto. Tenerlo a -20 ° C per 1 ora. </li><li> Tagliare cuore direttamente nella matrice con una lama di rasoio con una trasversale. Assicurarsi che ogni fetta ha uno spessore di 2 mm. Tagliare circa 5 - 7 diapositive per ogni cuore (in base al livello rimodellamento); questo è chiamato campionamento sistematico. </li><li> A questo punto, eseguire la colorazione cloruro di 2,3,5-trifeniltetrazolio (TTC) è facoltativo (mantenere l&#39;orientamento del cuore fette base-apice). <ol><li> Incubare in 1% TTC in PBS per 50 min a 37 ° C. Incubare in 4% paraformaldeide (PFA) per 20 minuti a 1 ora. Mettere le sezioni between due lastre di vetro con distanziatori 2 mm e scattare foto con un microscopio stereologica accoppiato con una macchina fotografica a 15X di ingrandimento. ATTENZIONE! Paraformaldeide è tossico. </li></ol></li><li> Far scorrere il congelamento (1 opzione st) <ol><li> Mettere ciascun vetrino in uno stampo di plastica (10 x 10 x 5 mm) con supporto per cryotomy (temperatura di taglio ottimale, OCT) di montaggio, mantenere l&#39;orientamento (posizionare il lato apice orientata della sezione giù sul fondo dello stampo). Congelare i blocchi con vapori 2-metilbutano sotto azoto liquido di raffreddamento per 10 - 15 minuti. Infine, memorizzare il tessuto a -80 ° C. </li></ol></li><li> Paraffinization (opzione 2 nd) <ol><li> Posizionare ciascuna diapositiva incorporamento cassette (mantenere l&#39;orientamento posizionando il lato apice orientata della sezione sul fondo della cassetta) e poi in 4% PFA per 24 ore. Mettere in una macchina durante la notte processatore. <ol><li> Incubare in etanolo al 70% per 2 ore. Incubare a Ethanol 95% per 2 ore. Incubare in etanolo 100% per 3 ore. Incubare in xilolo per 4 ore. Incubare in paraffina (fuso a 60 ° C in forno) per 5 ore. Infine, fare blocchi, grazie all&#39;integrazione di ogni diapositiva cuore in paraffina. </li></ol></li></ol></li></ol> 3. Masson-Goldner colorazione tricromica <ol><li> Rendere sezioni di tessuto da blocchi di paraffina con un microtomo manuale (spessore 5 um) o dai blocchi oltremare con un criostato impostato a -18 ° C (spessore 7 micron). </li><li> Macchia un vetrino da ogni parte del cuore per ogni ratto (3 - 4 sezioni trasversali per vetrino) con Masson-Goldner colorazione tricromica (vedi allegato). NOTA: Inizia da questo passaggio per le sezioni di paraffina. <ol><li> Sciogliere i vetrini a 60 ° C in un forno. Sotto una cappa aspirante, li Deparaffinare in xilolo due volte per 10 minuti ciascuno. li Reidratare in 100% di etanolo, 95% di etanolo, 70% di etanolo e acqua distillata per 3 minuti ciascuno. NOTA: Inizia da questo passaggio per il cryosectionS. </li><li> fissarli in Bouin soluzione durante la notte. Poi, sciacquarli sotto acqua corrente per 10 - 15 minuti. Sciacquare con acqua distillata. incubare in ematossilina di Mayer per 3 min. </li><li> Rimuovere le diapositive e lasciarli in acqua distillata per 5 min. Poi, incubare in acido Fuchsin-Ponceau per 5 min. Risciacquare in acido acetico 1% per 1 min. </li><li> Poi, incubare in acido fosfomolibdico Arancio G per 1 min. Risciacquare in acido acetico 1% per 1 min, incubare a colorante verde luce per 10 minuti, e sciacquare in acido acetico 1% per 1 min. </li><li> li Disidratare in etanolo al 70% (30 sec), 95% di etanolo (30 sec), e il 100% di etanolo (5 min). Mettere una goccia di un mezzo di montaggio resinoso sulle sezioni di tessuto, coprire con coprioggetto, e lasciarli asciugare. </li></ol></li></ol> 4. Infarct Size Analysis <ol><li> Acquisire una immagine da ogni diapositiva su uno stereomicroscopio (15x) accoppiato con una macchina fotografica. Fotografare un righello con la stessa impostazioneS. </li><li> Utilizzare immagine software di analisi per misurare lo spessore della cicatrice in mezzo dell&#39;infarto, lo spessore del setto, la zona della cavità ventricolo sinistro (LV), la zona dell&#39;infarto, e l&#39;area di tessuto LV utilizzando. <ol><li> Impostare la scala con l&#39;immagine righello (Figura 1A). <ol><li> Clicca su misurazioni quindi selezionare Imposta fattore di conversione. Tracciare una linea sulla barra di calibrazione. Fare clic destro sull&#39;immagine e cliccare su taratura finale. Si noti il valore bar, e quindi fare clic su OK. </li></ol></li><li> Selezionare il LV dalla foto del cuore colorato (Figura 1B). Utilizzare lo strumento segmento multiplo. Selezionare il punto per punto LV, e quindi fare clic destro Copia / incolla da nessuna parte. </li><li> Misurare lo spessore della cicatrice e membrana con lo strumento di misurazione singolo segmento (Figura 1C </strong&gt;). </li><li> Rileva automaticamente il LV cavità, infarto, e le aree LV utilizzando lo strumento di misurazione locale automatico in modalità RGB (Figura 1D). <ol><li> Fare clic sullo strumento. Attiva solo Bordi e Contigui in modalità RGB. Infine, fare clic all&#39;interno dell&#39;area di interesse per rilevarla. Se necessario, utilizzare strumenti di precisione. </li></ol></li></ol></li><li> Calcolare le dimensioni dell&#39;infarto come rapporto dell&#39;area infartuata all&#39;area LV. </li><li> Calcolare l&#39;indice di espansione come segue: [LV zona cavità / intera area LV] / [spessore infarto / spessore del setto], con l&#39;intera area LV comprendente sia la cavità LV e aree di tessuto LV. </li><li> Infine, calcolare un &quot;medio&quot; per ogni cuore come segue: [media dell&#39;indice di espansione dalle diapositive infartuati] * [numero di diapositive infartuati / numero totale di diapositive]. </li></ol>

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The authors have nothing to disclose.

I passaggi critici all&#39;interno del protocollo tessuto fibrotico può essere valutata con precisione in un modello di ratto MI cronica con campionamento sistematico del cuore e l&#39;immagine raccolta analisi di sezioni istologiche tricromatiche macchiato ottenuti dalla base all&#39;apice. Due passi sono particolarmente importanti per l&#39;attuazione del protocollo di successo. In primo luogo, l&#39;uso di KCl per la raccolta cardiaca permette il muscolo cardiaco per ess...

Infarto del miocardio (MI) è una delle principali cause di morte e disabilità in tutto il mondo. La malattia coronarica è la causa principale; MI deriva da ischemia consecutivo a eventi coronarici quali l&#39;occlusione. Quando riperfusione non viene eseguita entro le prime 6 ore, ischemia induce necrosi miocardica irreversibile. Nei pazienti, la caratterizzazione di MI si basa su diversi strumenti diagnostici, tra cui i segni clinici, elettrocardiogramma, valutazione dei livelli plasmatici di biomarcatori, l&#39;ecocardiografia, risonanza magnetica per immagini, e istologica analisi 1. Acuta e cronica MI sono classificati in due diverse fasi di pregiudizio secondo i tempi della necrosi miocardica rispetto al tempo della occlusione coronarica. La fase acuta, che si verificano durante i primi 7 giorni, è associato con la perdita di cardiomiociti, infiammazione estesa, e il reclutamento di fibroblasti. La fase sub-acuta, caratterizzata da guarigione del tessuto cardiaco e la formazione di una cicatrice, si verificatra 1 e 4 - 6 settimane. Espansione dell&#39;infarto, assottigliamento della parete del ventricolo, e il ventricolo dilatazione caratterizzano la fase cronica. Ampia rimodellamento del ventricolo sinistro si traduce progressivamente in grave insufficienza cardiaca 2. MI indotta da permanente discendente anteriore sinistra (LAD) legatura rappresenta il modello roditore livello di infarto miocardico cronico. I imita legatura coronarie l&#39;occlusione coronarica. Le dimensioni dell&#39;infarto dipende dal sito della legatura. Caratterizzazione di danno ischemico del miocardio in un modello di roditore è classicamente eseguita utilizzando i livelli plasmatici di biomarker, come la troponina I e T 3, l&#39;ecocardiografia, risonanza magnetica, e istologia 4,5. livelli di biomarker sono correlati con l&#39;entità della morte dei cardiomiociti. L&#39;ecocardiografia valuta la funzione ventricolare sinistra di valore derivante da anomalie di movimento della parete regionali. Inoltre, le tecniche di imaging non invasive, come la risonanza magnetica o ad alta risoluzioneecocardiografia, permetta la valutazione della riduzione di movimento della parete, il volume dell&#39;area cicatriziale con ridotta perfusione e miocardio vitale, e l&#39;assottigliamento della parete. dimensioni LV permettono la valutazione accurata della dimensione dell&#39;infarto. Infine, la quantificazione del miocardio vitale e morti può essere eseguita un&#39;autopsia con macchie specifiche di sezioni istologiche di cuori raccolte e consente la verifica della dimensione dell&#39;infarto (IS). Un&#39;altra caratteristica importante è la valutazione dell&#39;indice di espansione dell&#39;infarto (EI) 6. L&#39;EI è associato con l&#39;infarto transmurale e inizia entro i primi 3 giorni. L&#39;EI è caratterizzata da una progressiva riduzione di spessore della parete, un aumento delle dimensioni della cavità LV, e conseguenti cambiamenti di forma LV. Per valutare l&#39;efficacia terapeutica di nuovi trattamenti - in particolare, le strategie di rigenerazione basata su cellule, matrici, e gene valutazione delivery-accurata MI nei roditori è di fondamentale importanza.Quando misurato su una singola sezione trasversale ottenuta a livello muscolo papillare, la dimensione IS può essere polarizzato a causa della grande variabilità che esiste nello sviluppo dell&#39;infarto seguente legatura LAD; l&#39;infarto apice potrebbe essere poi occultato. È importante sottolineare che le metodologie più accurate alle dimensioni MI determinato sono stati descritti per topi o ratti 7-9 10. Tuttavia, IS è insufficiente per quantificare con precisione LV rimodellamento o riduzioni terapeuticamente indotte (o prevenzioni) del rimodellamento. Infatti, IS è comunemente espressa come percentuale del volume totale LV valutata su sezioni trasversali del cuore. Anche se questo metodo è valido per infarto miocardico acuto, l&#39;assottigliamento della parete LV si verificano durante il rimodellamento rimane sotto-valutato 11,12. Una completa quantificazione morfometrica delle dimensioni dell&#39;infarto e cambiamenti strutturali dovrebbe quantificare diversi parametri, quali la lunghezza endocardici ed epicardici e diametri, così come infarto e zone sane. Descriviamo un appr metodologicaoach per valutare con precisione MI e rimodellamento in un modello di ratto cronica.

<table><tbody><tr><td>Acrylic rat heart matrix 2 mm</td><td>72-5015</td><td>Harvard Appartus</td><td></td></tr><tr><td>Inspira advanced volume controlled ventilator</td><td>Harvard Apparatus</td><td>557058</td><td></td></tr><tr><td>Catheter Insyte 14 G</td><td>BD</td><td>381267</td><td></td></tr><tr><td>O.C.T</td><td>BDHA361603E</td><td>VWR</td><td></td></tr><tr><td>TTC</td><td>T8877-10G</td><td>Sigma Aldrich</td><td></td></tr><tr><td>Mayer hematoxylin</td><td>MHS32-1L</td><td>Sigma Aldrich</td><td></td></tr><tr><td>Acid Fuchsin&lt;br/&gt; CI 42685</td><td>F8129-50G</td><td>Sigma Aldrich</td><td></td></tr><tr><td>Ponceau Xylidin&lt;br/&gt; CI 16150</td><td>P2395-25G</td><td>Sigma Aldrich</td><td></td></tr><tr><td>Orange G&lt;br/&gt; CI 16230</td><td>O3756-100G</td><td>Sigma Aldrich</td><td></td></tr><tr><td>Light green&lt;br/&gt; CI 42095</td><td>L5382-25G</td><td>Sigma Aldrich</td><td></td></tr><tr><td>KCl</td><td>P9333-500G</td><td>Sigma Aldrich</td><td></td></tr><tr><td>Xylol</td><td>10315083</td><td>HoneyWell</td><td></td></tr><tr><td>Ethanol absolute</td><td>10303990</td><td>HoneyWell</td><td></td></tr><tr><td>2-methylbutane</td><td>M32631-1L</td><td>Sigma Aldrich</td><td></td></tr><tr><td>Stereogical microscope</td><td>SM2800</td><td>Nikon</td><td></td></tr><tr><td>Formaldehyde</td><td>99340</td><td>Reactolab</td><td></td></tr><tr><td>Embedding cassette</td><td>K113.1</td><td>Carl Roth</td><td></td></tr><tr><td>Bersoft Image measurement Software</td><td></td><td>Bersoft.com</td><td>Licensed software</td></tr></tbody></table>

histological quantification of chronic myocardial infarct in rats

Myocardial infarction is defined as cardiomyocyte death due to prolonged ischemia; an inflammatory response and scar formation (fibrosis) follow the ischemic injury. Following the initial acute phase, chronic remodeling of the left ventricle (LV) modifies the structure and function of the heart. Permanent coronary ligation in small animals has been widely used as a reference model for a chronic model of MI. Thinning of the infarcted wall progressively develops to transmural fibrosis. Histological assessment of infarct size is commonly performed; nevertheless, a standardization of the methods for quantification is missing. Indeed, important methodological aspects, such as the number of sections analyzed and the sampling and quantification methods, are usually not described and therefore preclude comparison across investigations. Too often, quantification is performed on a single section obtained at the level of the papillary muscles. Because novel strategies aimed at reducing infarct expansion and remodeling are under investigation, there is an important need for the standardization of accurate heart sampling protocols. We describe an accurate method to quantify the infarct size using a systematic sampling of harvested rat heart and image analyses of trichromatic stained histological sections obtained from base to apex. We also provide evidence that calculating the expansion index (EI) allowed for infarct size assessment, taking into account changes of the left ventricle throughout the remodeling.

Sei settimane post-LAD legatura, cuori sono state raccolte da ratti di Lewis. sezioni di tessuto 2 mm, sono state ottenute dall&#39;apice alla base. Una procedura di colorazione TTC è stata effettuata per visualizzare l&#39;area infartuale, che appare in bianco, e il miocardio sano, che appare in rosso (Figura 2). A seconda del sito di legatura LAD, le dimensioni dell&#39;infarto varia. Per le grandi MI, infarti transmurale sono stati osservati dal vertice alla base <st...

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Histological Quantification of Chronic Myocardial Infarct in Rats

The post-mortem assessment of myocardial infarction (MI) in rodents is based on quantification of the infarct on stained heart sections. We describe an accurate method to quantify the infarct size using systematic sampling of harvested rat hearts from base to apex and image analyses of trichrome-stained histological sections.

Quantificazione istologica di cronica Myocardial Infarto in Rats

Myocardial infarction is defined as cardiomyocyte death due to prolonged ischemia; an inflammatory response and scar formation (fibrosis) follow the ...

histological-quantification-of-chronic-myocardial-infarct-in-rats

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14.4K Views.  University of Fribourg. The post-mortem assessment of myocardial infarction (MI) in rodents is based on quantification of the infarct on stained heart sections. We describe an accurate method to quantify the infarct size using systematic sampling of harvested rat hearts from base to apex and image analyses of trichrome-stained histological sections. 

Video: Histological Quantification of Chronic Myocardial Infarct in Rats

Coronary Artery Ligation and Intramyocardial Injection in a Murine Model of Infarction

Mouse models are a valuable tool for studying acute injury and chronic remodeling of the myocardium in vivo. With the advent of genetic modifications to the whole organism or the myocardium and an array of biological and/or synthetic materials, there is great potential for any combination of these to assuage the extent of acute ischemic injury and impede the onset of heart failure pursuant to myocardial remodeling. 
Here we present the methods and materials used to reliably perform this microsurgery and the modifications involved for temporary (with reperfusion) or permanent coronary artery occlusion studies as well as intramyocardial injections. The effects on the heart that can be seen during the procedure and at the termination of the experiment in addition to histological evaluation will verify efficacy. 
Briefly, surgical preparation involves anesthetizing the mice, removing the fur on the chest, and then disinfecting the surgical area. Intratracheal intubation is achieved by transesophageal illumination using a fiber optic light. The tubing is then connected to a ventilator. An incision made on the chest exposes the pectoral muscles which will be cut to view the ribs. For ischemia/reperfusion studies, a 1 cm piece of PE tubing placed over the heart is used to tie the ligature to so that occlusion/reperfusion can be customized. For intramyocardial injections, a Hamilton syringe with sterile 30gauge beveled needle is used. When the myocardial manipulations are complete, the rib cage, the pectoral muscles, and the skin are closed sequentially. Line block analgesia is effected by 0.25% marcaine in sterile saline which is applied to muscle layer prior to closure of the skin. The mice are given a subcutaneous injection of saline and placed in a warming chamber until they are sternally recumbent. They are then returned to the vivarium and housed under standard conditions until the time of tissue collection. At the time of sacrifice, the mice are anesthetized, the heart is arrested in diastole with KCl or BDM, rinsed with saline, and immersed in fixative. Subsequently, routine procedures for processing, embedding, sectioning, and histological staining are performed. 
Nonsurgical intubation of a mouse and the microsurgical manipulations described make this a technically challenging model to learn and achieve reproducibility. These procedures, combined with the difficulty in performing consistent manipulations of the ligature for timed occlusion(s) and reperfusion or intramyocardial injections, can also affect the survival rate so optimization and consistency are critical.

Numerous genetic manipulations and/or intramyocardial injections of genes, proteins, cells, and/or biomaterials are superimposed upon the dimension of time in studies of acute ischemia/ reperfusion injury and chronic remodeling in mice. This video illustrates the microsurgical procedures for ischemia/reperfusion, permanent coronary artery ligation, and intramyocardial injection studies.

Legatura dell&#39;arteria coronarica e di iniezione intramiocardico in un modello murino di infarto

Mouse models are a valuable tool for studying acute injury and chronic remodeling of the myocardium in vivo.  With the advent of genetic modifications to ...

Ricerca

Medicina

In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography

The use of Micro-Computed Tomography (MicroCT) for in vivo studies of small animals as models of human disease has risen tremendously due to the fact that MicroCT provides quantitative high-resolution three-dimensional (3D) anatomical data non-destructively and longitudinally. Most importantly, with the development of a novel preclinical iodinated contrast agent called eXIA160, functional and metabolic assessment of the heart became possible. However, prior to the advent of commercial MicroCT scanners equipped with X-ray flat-panel detector technology and easy-to-use cardio-respiratory gating, preclinical studies of cardiovascular disease (CVD) in small animals required a MicroCT technologist with advanced skills, and thus were impractical for widespread implementation. The goal of this work is to provide a practical guide to the use of the high-speed Quantum FX MicroCT system for comprehensive determination of myocardial global and regional function along with assessment of myocardial perfusion, metabolism and viability in healthy mice and in a cardiac ischemia mouse model induced by permanent occlusion of the left anterior descending coronary artery (LAD).

In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography

This method outlines the use of Quantum Micro-Computed Tomography (MicroCT) to assess cardiac morphology, function, perfusion, metabolism and viability with iodinated contrast agent in mice with experimentally-induced myocardial ischemia. The technique can be applied for non-destructive high-throughput longitudinal in vivo imaging of various animal models of human heart disease.

In Vivo quantitativa valutazione della struttura del miocardio, la funzione, la perfusione e sostenibilità Utilizzando cardiaca micro-tomografia computerizzata

The use of Micro-Computed Tomography (MicroCT) for in vivo studies of small animals as models of human disease has risen tremendously due to the fact that ...

Bioingegneria

Minimal Invasive Surgical Procedure of Inducing Myocardial Infarction in Mice

Myocardial infarction still remains the main cause of death in western countries, despite considerable progress in the stent development area in the last decades. For clarification of the underlying mechanisms and the development of new therapeutic strategies, the availability of valid animal models are mandatory. Since we need new insights into pathomechanisms of cardiovascular diseases under in vivo conditions to combat myocardial infarction, the validity of the animal model is a crucial aspect. However, protection of animals are highly relevant in this context. Therefore, we establish a minimally invasive and simple model of myocardial infarction in mice, which assures a high reproducibility and survival rate of animals. Thus, this models fulfils the requirements of the 3R principle (Replacement, Refinement and Reduction) for animal experiments and assure the scientific information needed for further developing of therapeutical strategies for cardiovascular diseases.

A highly reproducible model for myocardial infarction in mice with minimal invasive manipulations is described. The model can be easily performed, resulting in a high reproducibility and survival rate. Thus, the described model will reduce the number of required animals as requested by the 3R principle (Replacement, Refinement and Reduction).

Minimal procedura chirurgica invasiva di indurre infarto miocardico nei topi

Myocardial infarction still remains the main cause of death in western countries, despite considerable progress in the stent development area in the last ...

Primary Outcome Assessment in a Pig Model of Acute Myocardial Infarction

Mortality after acute myocardial infarction remains substantial and is associated with significant morbidity, like heart failure. Novel therapeutics are therefore required to confine cardiac damage, promote survival and reduce the disease burden of heart failure. Large animal experiments are an essential part in the translational process from experimental to clinical therapies. To optimize clinical translation, robust and representative outcome measures are mandatory. The present manuscript aims to address this need by describing the assessment of three clinically relevant outcome modalities in a pig acute myocardial infarction (AMI) model: infarct size in relation to area at risk (IS/AAR) staining, 3-dimensional transesophageal echocardiography (TEE) and admittance-based pressure-volume (PV) loops. Infarct size is the main determinant driving the transition from AMI to heart failure and can be quantified by IS/AAR staining. Echocardiography is a reliable and robust tool in the assessment of global and regional cardiac function in clinical cardiology. Here, a method for three-dimensional transesophageal echocardiography (3D-TEE) in pigs is provided. Extensive insight into cardiac performance can be obtained by admittance-based pressure-volume (PV) loops, including intrinsic parameters of myocardial function that are pre- and afterload independent. Combined with a clinically feasible experimental study protocol, these outcome measures provide researchers with essential information to determine whether novel therapeutic strategies could yield promising targets for future testing in clinical studies.

Reliable and accurate outcome assessment is the key for translation of preclinical therapies into clinical treatment. The current paper describes how to assess three clinically relevant primary outcome parameters of cardiac performance and damage in a pig acute myocardial infarction model.

La valutazione dell&#39;outcome primario in un modello suino di infarto miocardico acuto

Mortality after acute myocardial infarction remains substantial and is associated with significant morbidity, like heart failure. Novel therapeutics are ...

Murine Myocardial Infarction Model using Permanent Ligation of Left Anterior Descending Coronary Artery

Myocardial infarction (MI) and acute coronary diseases are among the most prominent causes of death in population with western lifestyle. The murine models of MI with permanent ligation of left-anterior descending (LAD) coronary artery closely mimics MI in humans. Murine models benefit from the extensive genetic engineering available nowadays. Here we propose a reproducible murine surgical model of myocardial infarction by permanent LAD coronary ligation. Our technique comprises anesthesia with ketamine/xylazine that can be rapidly reversed by administration of an antagonist, intubation without tracheotomy for mechanical-assisted ventilation, ventilation with application of extrinsic positive end-expiratory pressure (PEEP) to avoid alveolar collapse, a thoracotomy method limiting to the minimum surgical lesions made to skeletal muscles, and lung inflation without thoracentesis. This method is sparsely invasive, reproducible and reduces post-surgery mortality and complications.

Herein we describe a surgical procedure showing how to achieve permanent ligation of the left-anterior descending coronary artery in mice. This model is of high relevance to investigate the pathophysiology of myocardial infarction and the concomitant biological processes.

Modello di infarto miocardico Murine utilizzando la legatura permanente dell'arteria coronaria discendente anteriore sinistra

Myocardial infarction (MI) and acute coronary diseases are among the most prominent causes of death in population with western lifestyle. The murine ...

A New Model of Heart Failure Post-Myocardial Infarction in the Rat

Ligation of the left anterior descending (LAD) coronary artery has been widely used to establish the rat model of heart failure (HF) post myocardial infarction (MI). However, the disadvantages of this model include high mortality rate after ligation and larger variations both in the infarct size and the degree of impaired cardiac function. In addition, a ventilator or exteriorization of the heart is indispensable for the previous models, which complicates the procedure during the ligation. In this study, we developed a reliable and reproducible model without the ventilator or exteriorization of the heart by ligating the LAD coronary artery. Four weeks after the procedure, we found that the serum concentrations of CK-MB, NT-proBNP, and Renin, which were used to assist diagnoses of MI and HF, were significantly higher in the MI group compared to the sham group. In contrast, the value of left ventricle ejection fraction (LVEF) in the MI group was obviously less than in the sham group. Furthermore, the infarct size and cardiac fibrosis area were individually confirmed and quantitatively analyzed by TTC staining and Masson's trichrome staining. Smaller variations were found in either infarct size or fibrosis area in the MI group, which helped to develop a reliable and reproducible model of HF post-MI. This new model of HF post-MI in the rat is vital for studying the potential mechanisms of MI and HF. This new method can be used to develop the new drug for treatment of MI and HF in rats by using pharmacological strategies.

We successfully developed a reliable and reproducible model of heart failure post-myocardial infarction in the rat without ventilation or exteriorization of the heart. This simplifies the procedure and benefits the further studies about the potential mechanisms behind the heart failure.

Ligation of the left anterior descending (LAD) coronary artery has been widely used to establish the rat model of heart failure (HF) post myocardial ...

An Intact Pericardium Ischemic Rodent Model

This protocol has shown that the pericardium and its contents play an essential anti-fibrotic role in the ischemic rodent model (coronary ligation to induce myocardial injury). The majority of pre-clinical myocardial infarction models require the disruption of pericardial integrity with loss of the homeostatic cellular milieu. However, recently a methodology has been developed by us to induce myocardial infarction, which minimizes pericardial damage and retains the heart&#39;s resident immune cell population. An improved cardiac functional recovery in mice with an intact pericardial space following coronary ligation has been observed. This method provides an opportunity to study inflammatory responses in the pericardial space following myocardial infarction. Further development of the labeling techniques can be combined with this model to understand the fate and function of pericardial immune cells in regulating the inflammatory mechanisms that drive remodeling in the heart, including fibrosis.

This protocol outlines the steps for inducing myocardial infarction in mice while preserving the pericardium and its contents.

Un modello di roditore ischemico del pericardio intatto

This protocol has shown that the pericardium and its contents play an essential anti-fibrotic role in the ischemic rodent model (coronary ligation to ...

Generation and Characterization of Right Ventricular Myocardial Infarction Induced by Permanent Ligation of the Right Coronary Artery in Mice

Right ventricular infarction (RVI) is a common presentation in clinical practice. Severe RVI can lead to fatal hemodynamic dysfunction and arrhythmia. In contrast to the extensively used mouse myocardial infarction (MI) model generated by left coronary artery ligation, the RVI mouse model is rarely employed due to the difficulty associated with model generation. Research on the mechanisms and treatment of RVI-induced RV remodeling and dysfunction requires animal models to mimic the pathophysiology of RVI in patients. This study introduces a feasible procedure for RVI model generation in C57BL/6J mice. Further, this model was characterized based on the following: infarct size evaluation at 24 h after MI, assessment of cardiac remodeling and function with echocardiography, RV hemodynamics assessment, and histology of the infarct zone at 4 weeks after RVI. In addition, a coronary vasculature cast was performed to observe the coronary arterial arrangement in RV. This mouse model of RVI would facilitate the research on mechanisms of right heart failure and seek new therapeutic targets of RV remodeling.

There are several differences between the right and left ventricles. However, the pathophysiology of right ventricular infarction (RVI) has not been clarified. In the present protocol, a reproducible method for RVI mouse model generation is introduced, which may provide a means to explain the mechanism of RVI.

Generazione e caratterizzazione dell'infarto miocardico ventricolare destro indotto dalla legatura permanente dell'arteria coronaria destra nei topi

Right ventricular infarction (RVI) is a common presentation in clinical practice. Severe RVI can lead to fatal hemodynamic dysfunction and arrhythmia. In ...

Ultrasound-Guided Induced Pluripotent Stem Cell-Derived Cardiomyocyte Implantation in Myocardial Infarcted Mice

The key objective of cell therapy after myocardial infarction (MI) is to effectively enhance the cell grafted rate, and human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are a promising cell source for cardiac repair after ischemic damage. However, a low grafted rate is a significant obstacle for effective cardiac tissue regeneration after transplantation. This protocol shows that multiple hiPSC-CM ultrasound-guided percutaneous injections into an MI area effectively increase cell transplantation rates. The study also describes the entire hiPSC-CM culture process, pretreatment, and ultrasound-guided percutaneous delivery methods. In addition, the use of human mitochondrial DNA help detect the absence of hiPSC-CMs in other mouse organs. Lastly, this paper describes the changes in cardiac function, angiogenesis, cell size, and apoptosis at the infarcted border zone in mice 4 weeks after cell delivery. It can be concluded that echocardiography-guided percutaneous injection of the left ventricular myocardium is a feasible, relatively invasive, satisfactory, repeatable, and effective cellular therapy.

Ultrasound-guided cell delivery around the site of myocardial infarction in mice is a safe, effective, and convenient way of cell transplantation.

Impianto di cardiomiociti derivati da cellule staminali pluripotenti indotte ecoguidate in topi infartuati miocardici

The key objective of cell therapy after myocardial infarction (MI) is to effectively enhance the cell grafted rate, and human induced pluripotent stem ...

An Experimental Model of Myocardial Infarction for Studying Cardiac Repair and Remodeling in Knockout Mice

Cardiovascular disease is the most prevalent cause of death in Western countries, with acute myocardial infarction (MI) being the most prevalent form. This paper describes a protocol for studying the role of galectin 3 (Gal-3) in the temporal evolution of cardiac healing and remodeling in an experimental animal model of MI. 
The procedures described include an experimental model of MI with a permanent coronary ligature in male C57BL/6J (control) and Gal-3 knockout (KO) mice, an echocardiography procedure to study cardiac remodeling and systolic function in vivo, a histological evaluation of interstitial myocardial fibrosis with picrosirius red-stained and rhodamine-conjugated lectin-stained sections for studying myocyte hypertrophy by the cross-sectional area (MCSA), and the quantification of infarct size and cardiac remodeling (scar thinning, septum thickness, and expansion index) by planimetry in slices stained with Masson's trichrome and triphenyl tetrazolium chloride. Gal-3 KO mice with MI showed disrupted cardiac remodeling and an increase in the scar thinning ratio and the expansion index. At the onset of MI, myocardial function and cardiac remodeling were also severely affected. At 4 weeks post MI, the natural evolution of fibrosis in infarcted Gal-3 KO mice was also affected. 
In summary, the experimental model of MI is a suitable model for studying the temporal evolution of cardiac repair and remodeling in mice with the genetic deletion of Gal-3 and other animal models. The lack of Gal-3 affects the dynamics of cardiac repair and disrupts the evolution of cardiac remodeling and function after MI.

Here, we describe an experimental model of myocardial infarction, an echocardiography procedure to study cardiac remodeling and function, and procedures for quantifying fibrosis and hypertrophy in picrosirius red-stained and rhodamine-stained sections, as well as the infarct size and expansion index in slices stained with Masson's trichrome.

Cardiovascular disease is the most prevalent cause of death in Western countries, with acute myocardial infarction (MI) being the most prevalent form. ...

Quantificazione istologica di cronica Myocardial Infarto in Rats

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Legatura dell'arteria coronarica e di iniezione intramiocardico in un modello murino di infarto