Los autores agradecen a Christiane Pahrmann por su asistencia técnica y la histología de realizar.

<html> Ratones Balb / c con un peso mínimo de 20g a la edad de 8 a 12 semanas son adquiridos de Charles River (Sandhofer Weg 7, D-97633 Sulzfeld). Los ratones se encuentran en condiciones convencionales, alimentados pellets ratón estándar y agua ad libitum. Anestesiar a ratones con isoflurano (2%) con una cámara de inducción. <ol><li> Afeitarse el área del cuello y la parte izquierda de la caja torácica y desinfectar con etanol al 80%. </li><li> Coloque el ratón sobre la espalda y colocar una máscara sobre su nariz y la boca para mantener la anestesia. </li><li> Comprobar los reflejos pellizcar la cola y las patas traseras para asegurarse de que el ratón es suficiente anestesiado. </li><li> Bajo visión microscópica realizar una incisión cervical que separa la piel, músculo y tejido que cubre la tráquea. </li><li> Cuando la tráquea se expone un agujero pequeño en el tejido entre los dos anillos de cartucho debajo de la glotis para insertar el tubo endotraqueal (Figura 1). Inserte el tubo endotraqueal la celebración de la parte craneal de la tráquea utilizando micro forecepts quirúrgica. Comprobar el movimiento torácico para asegurarse de que ambos pulmones están bien ventiladas. </li><li> La frecuencia respiratoria (RR) debe ser de aproximadamente 110 por minuto, con una presión inspiratoria de 17 a 18 cm H 2 O. Ponga el ratón con cuidado, sobre su lado derecho, frente a su lado izquierdo. Realizar una toracotomía leftsided entre la 3 ª y la 4 ª costilla, y disecar el tejido y el músculo con cuidado, usando una Cauter para prevenir el sangrado. </li><li> Abrir el tórax con cuidado, una vez que el tórax se abre, busca el corazón, sin tocar el pulmón con un objeto afilado. Ahora quite la parte del saco pericárdico, que cubre el corazón. </li><li> La DA se encuentra entre la arteria pulmonar y la aurícula izquierda. Utilice una sutura de prolene 8-0 (Ethicon, Norderstedt, Alemania) para ligar la DA proximal con una sutura simple (Figura 2). </li><li> Colocar un tubo torácico (catéter 28G, venal), entre los días 4 y 5 de la costilla. </li><li> Cerrar la incisión torácica en capas, con 6-0 suturas de Prolene en ejecución (Ethicon, Norderstedt, Alemania) para adaptar las costillas y las suturas de Prolene 4-0 en ejecución (Ethicon, Norderstedt, Alemania) para cerrar la piel. </li><li> De drenaje en el tórax con la ayuda de una jeringa de 2 ml con cuidado (Figura 3). Coloque el ratón sobre la espalda. Ahora toma el tubo endotraqueal y adaptar los anillos traqueales cartucho con un solo punto con 7-0 suturas de prolene (Ethicon, Norderstedt, Alemania). </li><li> Coloque la mascarilla sobre el ratón y cerca de la piel con Prolene 4-0 sutura continua (Ethicon, Norderstedt, Alemania). </li></ol> Validación Existen diferentes posibilidades para confirmar el éxito de la DA-ligadura. La prueba de troponina se puede realizar 6 a 18 horas después de la cirugía, con sólo 150 litros de sangre sin necesidad de sacrificar al animal. La sangre se aplica a un kit de prueba de troponina personalizado (TROP T sensibles, Roche, Mannheim) (Figura 4). La troponina es una proteína reguladora de los filamentos de actina de las células musculares, hay diferentes isotipos de los tres tipos de músculos. La cTnI y cTnT isotipos se encuentran en el corazón y se liberan en la lesión tisular. La prueba estándar para la troponina T (cTnT) se basa en dos el corazón de anticuerpos monoclonales específicos, una trampa de la troponina en la muestra de sangre, el segundo es un marcador. El área infartada se pueden identificar macroscópicamente después de 3 días (Figura 5). TTC (2,3,5-trifenil tetrazolio cloruro) tinción de la viabilidad del tejido medidas utilizadas para evaluar el tamaño del infarto. Colorante azul de Evans (1,5%, 1,0 ml) en tampón fosfato salino (PBS) se inyecta en la cavidad del ventrículo izquierdo para medir el área de isquemia miocárdica. El ratón es la eutanasia y el corazón se cosecha y se seccionaron en rodajas. Los cortes de tejido se incuban en el TTC 1% solución de PBS, pH 7,4 a 37 ° C durante 20 minutos. Los tejidos se fijan en el 10% PBS-formalina tamponada noche a la mañana a 2-8 º C. TTC se administra ex vivo para teñir de azul de Evans-negativos áreas (Figura 6). Para el estudio histológico del ratón tiene que ser sacrificado, y el corazón tiene que ser incorporados para su posterior procesamiento. Después de realizar los cortes de parafina, los portaobjetos se tiñeron con H &amp; E (hematoxilina y eosina) o tricrómica para visualizar el tejido fibroso (Figura 7). <img src="/files/ftp_upload/1438/1438fig1.jpg" alt="Figura 1" /> Figura 1: tubo traqueal. 1A: Expuesta la traquea, después de la incisión cervical ventral. 1B: tráquea se abre dos anillos cartilaginosos caudal de la laringe. 1C: tubo traqueal se inserta en la tráquea. <img src="/files/ftp_upload/1438/1438fig2.jpg" alt="Figura 2" /> Figura 2: El corazón se expone a través de una toracotomía izquierda lado, la DA se liga. t &quot;&gt; <img src="/files/ftp_upload/1438/1438fig3.jpg" alt="Figura 3" /> Figura 3: Después de que el tórax se cierra, un drenaje pleural se realiza. El ratón está todavía bajo la anestesia. <img src="/files/ftp_upload/1438/1438fig4.jpg" alt="Figura 4" /> Figura 4: Aparecen dos líneas después de unos minutos cuando el test de troponina es positiva. <img src="/files/ftp_upload/1438/1438fig5.jpg" alt="Figura 5" /> Figura 5: Muestra el corazón explantado. 5A: Vista macroscópica del corazón con la zona isquémica con un color más pálido blanquecino. 5B: La sección transversal del corazón infartado, el área isquémica se muestra en la esquina superior derecha.

<ol>
	<li>Atkins, B. Z., Hueman, M. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cellular+cardiomyoplasty+improves+diastolic+properties+of+injured+Heart.">Cellular cardiomyoplasty improves diastolic properties of injured Heart.</a> J Surg Res. 85 (2), 234-242 (1999).</li><li>Jaquet, K., KT, K. r. a. u. s. e. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reduction+of+myocardial+scar+size+after+implantation+of+mesenchymal+stem+cells+in+rats:+what+is+the+mechanism.">Reduction of myocardial scar size after implantation of mesenchymal stem cells in rats: what is the mechanism.</a> Stem Cells Dev. 14 (3), 299-309 (2005).</li><li>Joung, B., Kim, I. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bone+marrow+mononuclear+stem+cells+transplanted+in+rat+infarct+myocardium+improved+the+electrical+conduction+without+evidence+of+proarrhythmic+effects.">Bone marrow mononuclear stem cells transplanted in rat infarct myocardium improved the electrical conduction without evidence of proarrhythmic effects.</a> Yonsei Med J. 48 (5), 754-764 (2007).</li></ol>

Financiamiento El presente estudio fue apoyado por la Universidad de Hamburgo Hospital (MK, Mujer habilitación de subvención), DFG (SS, SCHR992/3-1), ISHLT (TD, Premio de Investigación 2009). Declaración Todos los animales recibieron cuidados humanos de conformidad con los Principios de Cuidado de Animales de laboratorio, los experimentos con animales se realizaron de acuerdo con las directrices y normas establecidas por la Sociedad Nacional de Investigaciones Médicas y la Guía para el Cuidado y Uso de Animales de Laboratorio publicado por la Institutos Nacionales de Salud (National Institutes of Health publicación 85-23, revisado 1985). Todos los animales se obtuvieron de Charles River Laboratories (Sulzfeld, Alemania) y se mantuvieron en las instalaciones de cuidado de los animales del Hospital Universitario de Eppendorf en Hamburgo. Los animales recibieron comida estándar y agua ad libitum.

En resumen, este video visualiza el modelo LAD-ligadura de paso a paso e identifica LAD-ligaduras en los ratones como los procedimientos quirúrgicos fácilmente factible.

lad-ligation: a murine model of myocardial infarction

Modelos de investigación de infarto e isquemia miocárdica son esenciales para investigar los procesos agudos y crónicos patobiológicas y fisiopatológicas de la isquemia miocárdica y para desarrollar y optimizar el tratamiento futuro. Dos métodos diferentes de la creación de la isquemia miocárdica se llevan a cabo en roedores de laboratorio. El primer método es la creación de crio infarto, una técnica rápida pero inexacta, y un crio-pluma se aplica en la superficie del corazón (1-3). Usando este método, el científico no puede garantizar que la crio-cicatriz lleva a la isquemia, también un gran daño miocárdico se crea que muestra los efectos fisiopatológicos secundarios que no están relacionadas con el infarto de miocardio. El segundo método es la ligadura permanente de la arteria descendente anterior izquierda (LAD). Aquí la DA se liga con un solo punto, formando una isquemia que se puede ver casi de inmediato. Al cierre de la DA, no hay flujo de sangre adicional es permitida en esa zona, mientras que el tejido circundante de miocardio no es casi afectada. Este procedimiento quirúrgico imita los aspectos fisiopatológicos y patobiológicas ocurre en el infarto relacionado con la isquemia miocárdica. El método presentado en este vídeo se muestra el procedimiento quirúrgico de un modelo de infarto de ratón por la ligadura de la DA. Este modelo es conveniente para los estudios de patobiológicas y fisiopatológicos, así como inmunobiológicos en el infarto de miocardio. La técnica que se muestra ofrece una alta precisión y se correlaciona bien con los cortes histológicos.

Watch this Scientific Journal Video about LAD-Ligation: A Murine Model of Myocardial Infarction at JoVE.com

LAD-Ligation: A Murine Model of Myocardial Infarction

Este video muestra cómo utilizar un modelo rápido y fiable para estudiar los procesos patobiológicas y fisiopatológicos de la isquemia miocárdica.

LAD-Ligadura: un modelo murino de infarto de miocardio

Research models of infarction and myocardial ischemia are essential to investigate the acute and chronic pathobiological and pathophysiological processes ...

lad-ligation-a-murine-model-of-myocardial-infarction

Research

JoVE Journal

Biology

44.4K vistas.  University Heart Center Hamburg. Este video muestra cómo utilizar un modelo rápido y fiable para estudiar los procesos patobiológicas y fisiopatológicos de la isquemia miocárdica.

Video: LAD-Ligation: A Murine Model of Myocardial Infarction

Murine Pancreatic Islet Isolation

Páncreas murino aislamiento Islet

Investigación

Biología

Murine Model of Hindlimb Ischemia 

In the United States, peripheral arterial disease (PAD) affects about 10 million individuals, and is also prevalent worldwide. Medical therapies for symptomatic relief are limited. Surgical or endovascular interventions are useful for some individuals, but long-term results are often disappointing. As a result, there is a need for developing new therapies to treat PAD. The murine hindlimb ischemia preparation is a model of PAD, and is useful for testing new therapies. When compared to other models of tissue ischemia such as coronary or cerebral artery ligation, femoral artery ligation provides for a simpler model of ischemic tissue. Other advantages of this model are the ease of access to the femoral artery and low mortality rate. 
In this video, we demonstrate the methodology for the murine model of unilateral hindimb ischemia. The specific materials and procedures for creating and evaluating the model will be described, including the assessment of limb perfusion by laser Doppler imaging. This protocol can also be utilized for the transplantation and non-invasive tracking of cells, which is demonstrated by Huang et al.1.

Murine Model of Hindlimb Ischemia

The surgical procedure for induction of unilateral hindlimb ischemia is demonstrated, with confirmation of ischemia by laser Doppler perfusion imaging.

Modelo murino de isquemia Miembro Posterior

In the United States, peripheral arterial disease (PAD) affects about 10 million individuals, and is also prevalent worldwide.  Medical therapies for ...

Murine Renal Transplantation Procedure

Renal orthotopic transplantation in mice is a technically challenging procedure. Although the first kidney transplants in mice were performed by Russell et al over 30 years ago (1) and refined by Zhang et al years later (2), few people in the world have mastered this procedure. In our laboratory we have successfully performed 1200 orthotopic kidney transplantations with &gt; 90% survival rate. The key points for success include stringent control of reperfusion injury, bleeding and thrombosis, both during the procedure and post-transplantation, and use of 10-0 instead of 11-0 suture for anastomoses.
Post-operative care and treatment of the recipient is extremely important to transplant success and evaluation. All renal graft recipients receive antibiotics in the form of an injection of penicillin immediately post-transplant and sulfatrim in the drinking water continually. Overall animal health is evaluated daily and whole blood creatinine analyses are performed routinely with a portable I-STAT machine to assess graft function.

Renal transplantation in mice is a technically challenging procedure that requires careful post-operative care and treatment for success.

Procedimiento murino Trasplante Renal

Renal orthotopic transplantation in mice is a technically challenging procedure. Although the first kidney transplants in mice were performed by Russell ...

Rodent Working Heart Model for the Study of Myocardial Performance and Oxygen Consumption

Isolated working heart models have been used to understand the effects of loading conditions, heart rate and medications on myocardial performance in ways that cannot be accomplished in vivo. For example, inotropic medications commonly also affect preload and afterload, precluding load-independent assessments of their myocardial effects in vivo. Additionally, this model allows for sampling of coronary sinus effluent without contamination from systemic venous return, permitting assessment of myocardial oxygen consumption. Further, the advent of miniaturized pressure-volume catheters has allowed for the precise quantification of markers of both systolic and diastolic performance. We describe a model in which the left ventricle can be studied while performing both volume and pressure work under controlled conditions. 
In this technique, the heart and lungs of a Sprague-Dawley rat (weight 300-500 g) are removed en bloc under general anesthesia. The aorta is dissected free and cannulated for retrograde perfusion with oxygenated Krebs buffer. The pulmonary arteries and veins are ligated and the lungs removed from the preparation. The left atrium is then incised and cannulated using a separate venous cannula, attached to a preload block. Once this is determined to be leak-free, the left heart is loaded and retrograde perfusion stopped, creating the working heart model. The pulmonary artery is incised and cannulated for collection of coronary effluent and determination of myocardial oxygen consumption. A pressure-volume catheter is placed into the left ventricle either retrograde or through apical puncture. If desired, atrial pacing wires can be placed for more precise control of heart rate. This model allows for precise control of preload (using a left atrial pressure block), afterload (using an afterload block), heart rate (using pacing wires) and oxygen tension (using oxygen mixtures within the perfusate).

Isolated working heart models can be used to measure the effect of loading conditions, heart rate, and medications on myocardial performance and oxygen consumption. We describe methods for preparation of a rodent left heart working model that permits study of systolic and diastolic performance and oxygen consumption under various conditions.

Roedor de Trabajo Modelo del corazón para el estudio sobre los resultados de miocardio y el consumo de oxígeno

Isolated working heart models have been used to understand the effects of loading conditions, heart rate and medications on myocardial performance in ways ...

The Murine Choline-Deficient, Ethionine-Supplemented (CDE) Diet Model of Chronic Liver Injury

Chronic liver diseases, such as viral hepatitis, alcoholic liver disease, or non-alcoholic fatty liver disease, are characterized by continual inflammation, progressive destruction and regeneration of the hepatic parenchyma, liver progenitor cell proliferation, and fibrosis. The end-stage of every chronic liver disease is cirrhosis, a major risk factor for the development of hepatocellular carcinoma. To study processes regulating disease initiation, establishment, and progression, several animal models are used in laboratories. Here we describe a six-week time course of the choline-deficient and ethionine-supplemented (CDE) mouse model, which involves feeding six-week old male C57BL/6J mice with choline-deficient chow and 0.15% DL-ethionine-supplemented drinking water. Monitoring of animal health and a typical body weight loss curve are explained. The protocol demonstrates the gross examination of a CDE-treated liver and blood collection by cardiac puncture for subsequent serum analyses. Next, the liver perfusion technique and collection of different hepatic lobes for standard evaluations are shown, including liver histology assessments by hematoxylin and eosin or Sirius Red stainings, immunofluorescent detection of hepatic cell populations as well as transcriptome profiling of the liver microenvironment. This mouse model is suitable for studying inflammatory, fibrogenic, and liver progenitor cell dynamics induced through chronic liver disease and can be used to test potential therapeutic agents that may modulate these processes.

The Murine Choline-Deficient, Ethionine-Supplemented CDE Diet Model of Chronic Liver Injury

Here we describe a common method to induce chronic liver injury in mice by feeding of a choline-deficient and ethionine-supplemented (CDE) diet. We demonstrate health monitoring, liver perfusion, isolation, and preservation. A time course of six weeks can inform about liver injury, pathohistology, fibrosis, inflammatory, and liver progenitor cell responses.

El murino colina deficientes, suplementada con Ethionine (CDE) dieta de modelo de la lesión hepática crónica

Chronic liver diseases, such as viral hepatitis, alcoholic liver disease, or non-alcoholic fatty liver disease, are characterized by continual ...

A Murine Model of Vertical Sleeve Gastrectomy

Bariatric surgery, such as vertical sleeve gastrectomy (VSG), is a surgery of the gastrointestinal tract that is performed for the purpose of weight loss. Bariatric surgery is currently the most effective long-term treatment for obesity. In addition to weight loss, bariatric surgery produces additional health benefits such as remission of type 2 diabetes, remission of hypertension, and decreased risk of developing certain types of cancer. The mechanisms beyond weight loss for these benefits remain incompletely defined. Therefore, animal models of bariatric surgery are being developed and validated to identify the mechanisms leading to these benefits, with the goal of improving understanding of gastrointestinal physiology and identifying new therapeutic targets. VSG has become the most commonly performed bariatric procedure in the clinic in the United States because it is highly effective at producing weight loss and metabolic improvement, and is simpler to perform than other bariatric procedures. Therefore, we have developed and validated a murine model of VSG. This murine VSG model recapitulates many of the effects of VSG seen in humans, including improved glucose and blood pressure regulation. The method is based on isolation of the stomach, ligation of gastric vessels, and removal of 70% of the stomach by transecting along the greater curvature of the stomach. We have successfully applied this surgical protocol to various genetically modified mouse lines to define the mechanistic contributors to the benefits of VSG. Furthermore, this murine VSG model has been combined with other surgical techniques, to achieve deeper mechanistic insight. Therefore, this is a simple and versatile model for studying gastrointestinal physiology and the health benefits of bariatric surgery.

The following describes the performance of vertical sleeve gastrectomy in mice. This is a type of weight-loss surgery that involves removal of approximately 70% of the stomach.

Un modelo murino de gastrectomía en manga Vertical

Bariatric surgery, such as vertical sleeve gastrectomy (VSG), is a surgery of the gastrointestinal tract that is performed for the purpose of weight loss. ...

Mass Spectrometry Analysis to Identify Ubiquitylation of EYFP-tagged CENP-A (EYFP-CENP-A)

Studying the structure and the dynamics of kinetochores and centromeres is important in understanding chromosomal instability (CIN) and cancer progression. How the chromosomal location and function of a centromere (i.e., centromere identity) are determined and participate in accurate chromosome segregation is a fundamental question. CENP-A is proposed to be the non-DNA indicator (epigenetic mark) of centromere identity, and CENP-A ubiquitylation is required for CENP-A deposition at the centromere, inherited through dimerization between cell division, and indispensable to cell viability.
Here we describe mass spectrometry analysis to identify ubiquitylation of EYFP-CENP-A K124R mutant suggesting that ubiquitylation at a different lysine is induced because of the EYFP tagging in the CENP-A K124R mutant protein. Lysine 306 (K306) ubiquitylation in EYFP-CENP-A K124R was successfully identified, which corresponds to lysine 56 (K56) in CENP-A through mass spectrometry analysis. A caveat is discussed in the use of GFP/EYFP or the tagging of high molecular weight protein as a tool to analyze the function of a protein. Current technical limit is also discussed for the detection of ubiquitylated bands, identification of site-specific ubiquitylation(s), and visualization of ubiquitylation in living cells or a specific single cell during the whole cell cycle.
The method of mass spectrometry analysis presented here can be applied to human CENP-A protein with different tags and other centromere-kinetochore proteins. These combinatory methods consisting of several assays/analyses could be recommended for researchers who are interested in identifying functional roles of ubiquitylation.

Mass Spectrometry Analysis to Identify Ubiquitylation of EYFP-tagged CENP-A EYFP-CENP-A

CENP-A ubiquitylation is an important requirement for CENP-A deposition at the centromere, inherited through dimerization between cell division, and indispensable to cell viability. Here we describe mass spectrometry analysis to identify ubiquitylation of EYFP-tagged CENP-A (EYFP-CENP-A) protein.

Análisis de espectrometría de masas para identificar la ubiquitylación de CENP-A con etiqueta EYFP (EYFP-CENP-A)

Studying the structure and the dynamics of kinetochores and centromeres is important in understanding chromosomal instability (CIN) and cancer ...

A Murine Model of a Burn Wound Reconstructed with an Allogeneic Skin Graft

Trivial superficial wounds heal without complications by primary intention. Deep wounds, such as full thickness burns, heal by secondary intention and require surgical debridement and skin grafting. Successful integration of the donor graft into a recipient wound bed depends on timely recruitment of immune cells, robust angiogenic response and new extracellular matrix formation. The development of novel therapeutic agents, which target some key processes involved in wound healing, are hindered by the lack of reliable preclinical models with optimized objective assessment of wound closure. Here, we describe an inexpensive and reproducible model of experimental full thickness burn wound reconstructed with an allogeneic skin graft. The wound is induced on the dorsum surface of anaesthetized inbred wild type mice from the BALB/C and SKH1-Hrhr backgrounds. The burn is produced using a brass template measuring 10 mm in diameter, which is preheated to 80 &#176;C and delivered at a constant pressure for 20 s. Burn eschar is excised 24 hours after the injury and replaced with a full thickness graft harvested from the tail of a genetically similar donor mouse. No specialized equipment is required for the procedure and surgical techniques are straightforward to follow. The method may be effortlessly implemented and reproduced in most research settings. Certain limitations are associated with the model. Due to technical difficulties, the harvest of thinner split thickness skin grafts is not possible. The surgical method we describe here allows for the reconstruction of burn wounds using full thickness skin grafts. It may be used to carry out preclinical therapeutic testing.

The aim of this study was to develop a murine model of burn wound healing. A thermal burn was induced on the dorsal skin of mice using a preheated brass template. Burned tissue was debrided and overlaid with a skin graft harvested from the tail of a genetically similar donor mouse.

Un modelo murino de una herida de quemadura reconstruida con un injerto de piel alogénico

Trivial superficial wounds heal without complications by primary intention. Deep wounds, such as full thickness burns, heal by secondary intention and ...

The Establishment of a Murine Mandibular Molar Extraction Socket Healing Model

This study introduces the development of a molar extraction model in the murine mandible to provide a practicable model for studying alveolar bone regeneration and intramembranous ossification. C57/J6 mice were used to extract the mandibular first molar to establish this model. They were euthanized, and the bilateral mandibles harvested, at 1 week and 4 weeks post-surgery, respectively. Subsequent serial stereoscopic harvest, histological assessment, and immunofluorescence staining were performed to demonstrate successful surgery. Immediately after surgery, the stereoscopic images displayed an empty extraction socket. The hematoxylin and eosin (H&#38;E) at 1 week and Masson staining at 4 weeks post-surgery showed that the area of the original root was partially and fully filled with bone trabeculae, respectively. The immunofluorescence staining showed that, compared with the homeostasis side, the Sp7 expression increased at 1 week post-surgery, suggesting vigorous osteogenesis in the alveolar fossa. All these results demonstrated a practicable murine tooth extraction socket healing model. Upcoming studies revealing the mechanisms of jawbone defect healing or socket healing could adopt this method.

This protocol demonstrates step-by-step details of how to extract the mandibular first molar in the mouse. It provides an alternative method for researchers focusing on jawbone healing and regeneration.

El establecimiento de un modelo de curación del alvéolo de extracción molar mandibular murina

This study introduces the development of a molar extraction model in the murine mandible to provide a practicable model for studying alveolar bone ...

Exploración del rendimiento cardíaco dependiente de la FC mediante un protocolo de estimulación auricular

A Pacing-Controlled Procedure for the Assessment of Heart Rate-Dependent Diastolic Functions in Murine Heart Failure Models

Heart failure with preserved ejection fraction (HFpEF) is a condition characterized by diastolic dysfunction and exercise intolerance. While exercise-stressed hemodynamic tests or MRI can be used to detect diastolic dysfunction and diagnose HFpEF in humans, such modalities are limited in basic research using mouse models. A treadmill exercise test is commonly used for this purpose in mice, but its results can be influenced by body weight, skeletal muscle strength, and mental state. Here, we describe an atrial-pacing protocol to detect heart rate (HR)-dependent changes in diastolic performance and validate its usefulness in a mouse model of HFpEF. The method involves anesthetizing, intubating, and performing pressure-volume (PV) loop analysis concomitant with atrial pacing. In this work, a conductance catheter was inserted via a left ventricular apical approach, and an atrial pacing catheter was placed in the esophagus. Baseline PV loops were collected before the HR was slowed with ivabradine. PV loops were collected and analyzed at HR increments ranging from 400 bpm to 700 bpm via atrial pacing. Using this protocol, we clearly demonstrated HR-dependent diastolic impairment in a metabolically induced HFpEF model. Both the relaxation time constant (Tau) and the end-diastolic pressure-volume relationship (EDPVR) worsened as the HR increased compared to control mice. In conclusion, this atrial pacing-controlled protocol is useful for detecting HR-dependent cardiac dysfunctions. It provides a new way to study the underlying mechanisms of diastolic dysfunction in HFpEF mouse models and may help develop new treatments for this condition.

Autor destacado: Investigación de la función cardíaca dependiente de la FC en modelos de ratón a través de un nuevo enfoque de estimulación auricular 

The present protocol describes obtaining the pressure-volume relationship through transesophageal pacing, which serves as a valuable tool in evaluating diastolic function&#160;in mouse models of heart failure.

Un procedimiento controlado por estimulación para la evaluación de las funciones diastólicas dependientes de la frecuencia cardíaca en modelos murinos de insuficiencia cardíaca