This work was supported by the Deutsche Forschungsgemeinschaft (DU 1190/3-1).

Todos los experimentos con animales se realizaron de conformidad con la ley de protección animal Alemán (TierSchG). Los ratones fueron alojados y manipulen de conformidad con las buenas prácticas de los animales según la definición de FELASA (www.felasa.eu/guidelines.php) y el cuerpo nacional de bienestar animal de GV-SOLAS (www.gv-solas.de/index.html). El comité de bienestar de los animales de la Universidad de Friburgo, así como las autoridades locales (Regierungspräsidium Freiburg) aprobaron todos los experimentos con animales. 1. Manejo de Animales, Preparación e inducción de la inflamación <ol><li> Utilice 4-6 semanas de edad ratones machos con un rango de peso de 16 a 20 g. Nota: Si los ratones son más viejos o más pesado que presentan exceso de grasa que rodea el vaso, lo que limita la observación microscópica. </li><li> Esterilizar todas las herramientas y mesa microscopio antes de la cirugía. </li><li> Inyectar 20 mg / kg de LPS (lipopolisacárido) por vía intraperitoneal 4 horas antes de la microscopía en el ratón vivo para inducir una inflamm bacterianaación. </li><li> Precalentar una solución salina al 0,9% en un baño de agua a 37 ° C para humidificar la cámara de plástico y el tejido mesenterio. </li><li> Anestesiar al ratón con inyección intraperitoneal de ketamina (100 mg / kg) y xilazina (5 mg / kg) justo antes de que el procedimiento de microscopía. Anestesia alternativos se pueden utilizar, por ejemplo, 2% de inhalación de isoflurano. Confirmar anestesia adecuada por la pérdida de la respuesta a la estimulación refleja (dedo del pie o de la cola pellizco con una presión firme). </li><li> Depilar el abdomen usando una máquina de afeitar y quitar el pelo suelto con una gasa saturada con etanol al 70%. </li><li> Aplique un ungüento veterinario en los ojos del ratón para evitar la sequedad, mientras que bajo anestesia. </li></ol> 2. Cirugía <ol><li> Esterilizar el abdomen utilizando etanol al 70%. Este método no es un método estéril y podría ser letal al final del experimento. </li><li> Realice una laparotomía media: Abra la piel del abdomen usando pequeñas, pinzas curvas y pequeñas tijeras. Identificar el epivasos gastrical y abrir el peritoneo en la región de la línea alba, para proteger a los vasos. </li><li> Aplicar unas pocas gotas de solución salina precalentada en la cavidad abdominal para mantener el tejido húmedo. </li><li> Leucocitos y plaquetas de la etiqueta fluorescente mediante la inyección de 50 l rodamina 6G (1 mg / ml) retro-orbital tal como se describe antes 9,10. </li><li> Exteriorizar un bucle de lugar ileumand en una placa de Petri con un diámetro de 10 cm y asegúrese de mantener el tejido húmedo aplicando la 37 ° C precalentado solución salina (0,9%) cada dos minutos. </li></ol> 3. Microscopia intravital <ol><li> Coloque el ratón debajo del microscopio y traer la vena mesenterio con un diámetro de 200 a 300 micras en el centro de la vista. Elija un recipiente sin entorno de grasa visible. </li><li> No toque los recipientes mesenterio evitando así la estimulación del endotelio. Maneje el bucle íleon cautela. </li><li> Visualizar las interacciones célula endotelial de sangrecon un microscopio invertido o en posición vertical y una cámara usando un software de microscopio. Record sangre interacciones célula-endotelial de 1 min en 4 venas diferentes por ratón. </li><li> La eutanasia el ratón por dislocación cervical después de la finalización de los experimentos de imagen. </li></ol> 4. Análisis <ol><li> Llevar a cabo el análisis fuera de línea y cegado para todos los parámetros. Llevar a cabo análisis utilizando cualquier programa de software adecuado. </li><li> Confirme condiciones estables y interindividually comparables flujo sanguíneo en alta resolución de tiempo de cine-clips (velocidad de fotogramas máxima) se centraron en el flujo de glóbulos intraluminal. </li><li> Cuantificar el número de leucocitos de rodadura. Para ello trazar una línea vertical a través de la vena y contar todos los leucocitos que cruzan esta línea en 1 min. </li><li> Determinar la velocidad de laminación midiendo el tiempo una sola leucocitos necesita pasar una distancia de 50 m, mientras que de forma estable a rodar sobre el endotelio. Para ello, dibuja dos líneas verticales en una distancia de 50 m tediante la vena. <ol><li> Mida el tiempo de un leucocito representante deberá obtener de una línea a la other.Calculate la velocidad de los leucocitos al dividir 50 micras a través del tiempo necesario (m / s). </li></ol></li><li> Medir la adhesión de leucocitos en un campo de 0,04 mm 2. Para ello, dibuja un cuadrado con la longitud lateral de 200 micras en la vena. <ol><li> Cuente los leucocitos adherentes firmes, definidos como ningún movimiento visible durante 30 segundos, dentro de este cuadrado. </li></ol></li><li> Cuente el número de plaquetas con destino a uno de los leucocitos de cuantificar las interacciones de las plaquetas de leucocitos. </li></ol>

<ol>
	<li>Lehr, H. A., Vollmar, B., Vajkoczy, P., Menger, M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intravital+fluorescence+microscopy+for+the+study+of+leukocyte+interaction+with+platelets+and+endothelial+cells.">Intravital fluorescence microscopy for the study of leukocyte interaction with platelets and endothelial cells.</a> Methods in enzymology. 300, 462-481 (1999).</li><li>Atherton, A., Born, G. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+investigations+of+the+adhesiveness+of+circulating+polymorphonuclear+leucocytes+to+blood+vessel+walls.">Quantitative investigations of the adhesiveness of circulating polymorphonuclear leucocytes to blood vessel walls.</a> The Journal of physiology. 222, 447-474 (1972).</li><li>Duerschmied, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Serotonin+stimulates+platelet+receptor+shedding+by+tumor+necrosis+factor-alpha-converting+enzyme+(ADAM17).">Serotonin stimulates platelet receptor shedding by tumor necrosis factor-alpha-converting enzyme (ADAM17).</a> Journal of thrombosis and haemostasis : JTH. 7, 1163-1171 (2009).</li><li>Chauhan, A. K., 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=ADAMTS13:+a+new+link+between+thrombosis+and+inflammation.">ADAMTS13: a new link between thrombosis and inflammation.</a> The Journal of experimental medicine. 205, 2065-2074 (1084).</li><li>Baez, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+open+cremaster+muscle+preparation+for+the+study+of+blood+vessels+by+in+vivo+microscopy.">An open cremaster muscle preparation for the study of blood vessels by in vivo microscopy.</a> Microvascular research. 5, 384-394 (1973).</li><li>Leister, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+peritoneal+cavity+chamber+for+intravital+microscopy+of+the+liver+under+conditions+of+pneumoperitoneum.">A peritoneal cavity chamber for intravital microscopy of the liver under conditions of pneumoperitoneum.</a> Surgical endoscopy. 17, 939-942 (2003).</li><li>Duerschmied, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Platelet+serotonin+promotes+the+recruitment+of+neutrophils+to+sites+of+acute+inflammation+in+mice.">Platelet serotonin promotes the recruitment of neutrophils to sites of acute inflammation in mice.</a> Blood. 121, 1008-1015 (2013).</li><li>Herr, N., 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=Acute+fluoxetine+treatment+induces+slow+rolling+of+leukocytes+on+endothelium+in+mice.">Acute fluoxetine treatment induces slow rolling of leukocytes on endothelium in mice.</a> PloS one. 9, e88316 (2014).</li><li>Yardeni, T., Eckhaus, M., Morris, H. D., Huizing, M., Hoogstraten-Miller, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Retro-orbital+injections+in+mice.">Retro-orbital injections in mice.</a> Lab animal. 40, 155-160 (2011).</li><li>Steel, C. D., Stephens, A. L., Hahto, S. M., Singletary, S. J., Ciavarra, R. P. <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+the+lateral+tail+vein+and+the+retro-orbital+venous+sinus+as+routes+of+intravenous+drug+delivery+in+a+transgenic+mouse+model.">Comparison of the lateral tail vein and the retro-orbital venous sinus as routes of intravenous drug delivery in a transgenic mouse model.</a> Lab animal. 37, 26-32 (2008).</li><li>Duerschmied, D., Bode, C., Ahrens, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immune+functions+of+platelets.">Immune functions of platelets.</a> Thrombosis and haemostasis. 112, 678-691 (2014).</li><li>Wagner, D. D., Frenette, P. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+vessel+wall+and+its+interactions.">The vessel wall and its interactions.</a> Blood. 111, 5271-5281 (2008).</li><li>Gawaz, M., Fateh-Moghadam, S., Pilz, G., Gurland, H. J., Werdan, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Platelet+activation+and+interaction+with+leucocytes+in+patients+with+sepsis+or+multiple+organ+failure.">Platelet activation and interaction with leucocytes in patients with sepsis or multiple organ failure.</a> European journal of clinical investigation. 25, 843-851 (1995).</li><li>Sarma, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Increased+platelet+binding+to+circulating+monocytes+in+acute+coronary+syndromes.">Increased platelet binding to circulating monocytes in acute coronary syndromes.</a> Circulation. 105, 2166-2171 (2002).</li><li>Sumagin, R., Sarelius, I. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=TNF-alpha+activation+of+arterioles+and+venules+alters+distribution+and+levels+of+ICAM-1+and+affects+leukocyte-endothelial+cell+interactions.">TNF-alpha activation of arterioles and venules alters distribution and levels of ICAM-1 and affects leukocyte-endothelial cell interactions.</a> American journal of physiology. Heart and circulatory physiology. 291, H2116-H2125 (2006).</li></ol>

The authors have nothing to disclose.

Aquí se describe la preparación y el rendimiento de la microscopía intravital de las venas mesenterio de ratones in vivo. Este método nos da la oportunidad de observar las interacciones leucocito-endotelial y plaquetarios endotelial 11 directamente en el organismo vivo. Como una respuesta temprana a la inflamación del endotelio se activa e interactúa con los leucocitos y las plaquetas que resulta en la rodadura, la adherencia y la transmigración 12. Pero...

El propósito de este protocolo es para describir una técnica simplificada de la microscopía intravital de las venas mesenterio en ratones vivos para la observación directa de las interacciones leucocito-endotelial y de leucocitos de plaquetas bajo condiciones inflamatorias. Microscopía intravital fue desarrollado para estudiar las interacciones leucocito-endotelial in vivo en condiciones inflamatorias 1,2, que no es trivial pero importante para la comprensión de reclutamiento de leucocitos inflamatoria y función. El método se describe en este protocolo fue desarrollado en base a las publicaciones previamente publicados. Similar a la visualización de la incorporación de plaquetas en un trombo crece 3 y en paralelo a lo que se ha publicado a principios 4, una vena mesenterio exteriorizada es examinado por microscopía de luz transmitida. Hay varios otros modelos de la microscopía intra vitales tales como el músculo cremáster de ratas 5 o el hígado del ratón y ratas 6. Microscopía intravital de vena mesenterio se ha desarrollado y aplicado en los estudios previos por varios grupos. Hemos utilizado esta técnica para observar las diferencias en el reclutamiento de leucocitos entre los ratones de tipo salvaje y hydroxylase1 triptófano (TPH1) - / - ratones, que son deficientes de la serotonina no neuronal y comparado los resultados a ratones cuyos serotonina plaquetaria se farmacológicamente empobrecido por largo plazo aplicación de la recaptación de serotonina un inhibidor de la fluoxetina 7. También hemos examinado las interacciones leucocito-endotelial después del tratamiento con fluoxetina aguda 8. En este protocolo nos centramos en la microscopía intravital de venas mesenterio, ya que este modelo se puede realizar de forma rápida, y permite mediciones válidas de las interacciones leucocito-endotelio y plaquetas de leucocitos. Esto es mucho más difícil y lleva mucho tiempo en la microscopía intravital de otros órganos, como los huesos, el hígado, la piel o músculo cremáster. El modol se describe aquí es ideal para la evaluación reproducible de la interacción célula-célula inflamatoria después de challengeing con un estímulo inflamatorio, como la inyección intraperitoneal de lipopolisacárido.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Rhodamine 6G</td>
			<td>Sigma-Aldrich</td>
			<td>&#160;989-38-8</td>
			<td></td>
		</tr>
		<tr>
			<td>Lipopolysaccharides from Escherichia coli 055:B5</td>
			<td>Sigma-Aldrich</td>
			<td>L2637&#160;</td>
			<td></td>
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intravital microscopy of leukocyte-endothelial and platelet-leukocyte interactions in mesenterial veins in mice

Microscopía intravital es un método que se puede utilizar para investigar diferentes procesos en diferentes regiones y vasos en los animales vivos. En este protocolo, se describe la microscopía intravital de venas mesenterio. Esto se puede realizar en un corto período de tiempo con resultados reproducibles que muestran interacciones leucocito-endotelial in vivo. Se describe un entorno inflamatoria después del desafío LPS del endotelio. Sin embargo, en este modelo se puede aplicar diferentes tipos de afecciones inflamatorias, como la bacteriana, química o biológica e investigar la administración de fármacos y sus efectos directos sobre el animal vivo y su impacto en el reclutamiento de leucocitos. Este protocolo se ha aplicado con éxito a un número de diferentes tratamientos de ratones y sus efectos sobre la respuesta inflamatoria en los vasos. En este documento, se describe la visualización de los leucocitos y plaquetas mediante el etiquetado con fluorescencia éstos con rodamina 6G. Además, cualquier formación de imágenes específico puede ser performed usando dirigidos moléculas marcadas con fluorescencia.

Una visión general de la configuración experimental descrito en este protocolo se muestra en la Figura 1. Se muestra un ratón con un íleon de bucle exteriorizada y sus vasos, que se puede observar en la microscopía intravital. La Figura 2 muestra cierto grado de activación en los animales no tratados debido a el procedimiento en sí. Pero no hay casi ninguna de rodadura lenta o la adhesión firme de los leucocitos en comparación con los ratones tratados con LPS. Figura 2<...

Watch this Scientific Journal Video about Intravital Microscopy of Leukocyte-endothelial and Platelet-leukocyte Interactions in Mesenterial Veins in Mice at JoVE.com

Intravital Microscopy of Leukocyte-endothelial and Platelet-leukocyte Interactions in Mesenterial Veins in Mice

This simplified application of intravital microscopy of mesentery veins in mice can be used in different models of inflammation to observe leukocyte-endothelial and platelet-leukocyte interactions.

Interacciones intravital microscopía de leucocitos endoteliales y plaquetas de leucocitos en mesenterial venas en ratones

Intravital microscopy is a method that can be used to investigate different processes in different regions and vessels in living animals. In this ...

intravital-microscopy-leukocyte-endothelial-platelet-leukocyte

Research

JoVE Journal

Immunology and Infection

12.0K vistas.  Heart Center, University of Freiburg. This simplified application of intravital microscopy of mesentery veins in mice can be used in different models of inflammation to observe leukocyte-endothelial and platelet-leukocyte interactions.

Video: Intravital Microscopy of Leukocyte-endothelial and Platelet-leukocyte Interactions in Mesenterial Veins in Mice

Intravital Microscopy of the Inguinal Lymph Node

Lymph nodes (LN's), located throughout the body, are an integral component of the immune system. They serve as a site for induction of adaptive immune response and therefore, the development of effector cells. As such, LNs are key to fighting invading pathogens and maintaining health. The choice of LN to study is dictated by accessibility and the desired model; the inguinal lymph node is well situated and easily supports studies of biologically relevant models of skin and genital mucosal infection.
The inguinal LN, like all LNs, has an extensive microvascular network supplying it with blood. In general, this microvascular network includes the main feed arteriole of the LN that subsequently branches and feeds high endothelial venules (HEVs). HEVs are specialized for facilitating the trafficking of immune cells into the LN during both homeostasis and infection. How HEVs regulate trafficking into the LN under both of these circumstances is an area of intense exploration. The LN feed arteriole, has direct upstream influence on the HEVs and is the main supply of nutrients and cell rich blood into the LN. Furthermore, changes in the feed arteriole are implicated in facilitating induction of adaptive immune response. The LN microvasculature has obvious importance in maintaining an optimal blood supply to the LN and regulating immune cell influx into the LN, which are crucial elements in proper LN function and subsequently immune response. 
The ability to study the LN microvasculature in vivo is key to elucidating how the immune system and the microvasculature interact and influence one another within the LN. Here, we present a method for in vivo imaging of the inguinal lymph node. We focus on imaging of the microvasculature of the LN, paying particular attention to methods that ensure the study of healthy vessels, the ability to maintain imaging of viable vessels over a number of hours, and quantification of vessel magnitude. Methods for perfusion of the microvasculature with vasoactive drugs as well as the potential to trace and quantify cellular traffic are also presented. 
Intravital microscopy of the inguinal LN allows direct evaluation of microvascular functionality and real-time interface of the direct interface between immune cells, the LN, and the microcirculation. This technique potential to be combined with many immunological techniques and fluorescent cell labelling as well as manipulated to study vasculature of other LNs.

A technique for performing intravital microscopy of the inguinal lymph node (LN) is outlined. Such technique allows for real-time, in vivo study of the lymph node microvasculature and structure both during homeostasis and infection. This technique can be adapted to cell trafficking studies and to other lymph node sites.

Microscopia intravital de los ganglios linfáticos inguinales

Lymph nodes (LN's), located throughout the body, are an integral component of the immune system. They serve as a site for induction of adaptive immune ...

Investigación

Inmunología e Infección

Tracking Neutrophil Intraluminal Crawling, Transendothelial Migration and Chemotaxis in Tissue by Intravital Video Microscopy

The recruitment of circulating leukocytes from blood stream to the inflamed tissue is a crucial and complex process of inflammation1,2. In the postcapillary venules of inflamed tissue, leukocytes initially tether and roll on the luminal surface of venular wall. Rolling leukocytes arrest on endothelium and undergo firm adhesion in response to chemokine or other chemoattractants on the venular surface. Many adherent leukocytes relocate from the initial site of adhesion to the junctional extravasation site in endothelium, a process termed intraluminal crawling3. Following crawling, leukocytes move across endothelium (transmigration) and migrate in extravascular tissue toward the source of chemoattractant (chemotaxis)4. Intravital microscopy is a powerful tool for visualizing leukocyte-endothelial cell interactions in vivo and revealing cellular and molecular mechanisms of leukocyte recruitment2,5. In this report, we provide a comprehensive description of using brightfield intravital microscopy to visualize and determine the detailed processes of neutrophil recruitment in mouse cremaster muscle in response to the gradient of a neutrophil chemoattractant. To induce neutrophil recruitment, a small piece of agarose gel (~1-mm3 size) containing neutrophil chemoattractant MIP-2 (CXCL2, a CXC chemokine) or WKYMVm (Trp-Lys-Tyr-Val-D-Met, a synthetic analog of bacterial peptide) is placed on the muscle tissue adjacent to the observed postcapillary venule. With time-lapsed video photography and computer software ImageJ, neutrophil intraluminal crawling on endothelium, neutrophil transendothelial migration and the migration and chemotaxis in tissue are visualized and tracked. This protocol allows reliable and quantitative analysis of many neutrophil recruitment parameters such as intraluminal crawling velocity, transmigration time, detachment time, migration velocity, chemotaxis velocity and chemotaxis index in tissue. We demonstrate that using this protocol, these neutrophil recruitment parameters can be stably determined and the single cell locomotion conveniently tracked in vivo.

We describe a protocol of brightfield intravital microscopy for measuring dynamic neutrophil-endothelial cell interactions during neutrophil recruitment in response to the source of a neutrophil chemoattractant in vivo. Neutrophil intraluminal crawling, transendothelial migration and chemotaxis in mouse cremaster muscle tissue are visualized with time-lapsed video photography and tracked with ImageJ.

Seguimiento de Rastreo de neutrófilos intraluminal, la migración transendotelial y la quimiotaxis de los tejidos por microscopía de vídeo intravital

The recruitment of circulating leukocytes from blood stream to the inflamed tissue is a crucial and complex process of inflammation1,2. In the ...

Intravital Imaging of the Mouse Thymus using 2-Photon Microscopy

Two-photon Microscopy (TPM) provides image acquisition in deep areas inside tissues and organs. In combination with the development of new stereotactic tools and surgical procedures, TPM becomes a powerful technique to identify "niches" inside organs and to document cellular "behaviors" in live animals. While intravital imaging provides information that best resembles the real cellular behavior inside the organ, it is both more laborious and technically demanding in terms of required equipment/procedures than alternative ex vivo imaging acquisition. Thus, we describe a surgical procedure and novel "stereotactic" organ holder that allows us to follow the movements of Foxp3+ cells within the thymus.
Foxp3 is the master regulator for the generation of regulatory T cells (Tregs). Moreover, these cells can be classified according to their origin: ie. thymus-differentiated Tregs are called "naturally-occurring Tregs" (nTregs), as opposed to peripherally-converted Tregs (pTregs). Although significant amount of research has been reported in the literature concerning the phenotype and physiology of these T cells, very little is known about their in vivo interactions with other cells. This deficiency may be due to the absence of techniques that would permit such observations. The protocol described in this paper provides a remedy for this situation.
Our protocol consists of using nude mice that lack an endogenous thymus since they have a punctual mutation in the DNA sequence that compromises the differentiation of some epithelial cells, including thymic epithelial cells. Nude mice were gamma-irradiated and reconstituted with bone marrows (BM) from Foxp3-KIgfp/gfp mice. After BM recovery (6 weeks), each animal received embryonic thymus transplantation inside the kidney capsule. After thymus acceptance (6 weeks), the animals were anesthetized; the kidney containing the transplanted thymus was exposed, fixed in our organ holder, and kept under physiological conditions for in vivo imaging by TPM. We have been using this approach to study the influence of drugs in the generation of regulatory T cells.

We have developed novel laboratory tools and protocols for intravital imaging acquisition of the thymus. Our technique should help in the identification of &#x201C;niches&#x201D; within the thymus where T cell development occurs.

Imagen intravital del timo de ratón utilizando 2-Photon Microscopy

Two-photon Microscopy (TPM) provides image acquisition in deep areas inside tissues and organs. In combination with the development of new stereotactic ...

Intravital Microscopy of the Spleen: Quantitative Analysis of Parasite Mobility and Blood Flow

The advent of intravital microscopy in experimental rodent malaria models has allowed major advances to the knowledge of parasite-host interactions 1,2. Thus, in vivo imaging of malaria parasites during pre-erythrocytic stages have revealed the active entrance of parasites into skin lymph nodes 3, the complete development of the parasite in the skin 4, and the formation of a hepatocyte-derived merosome to assure migration and release of merozoites into the blood stream 5. Moreover, the development of individual parasites in erythrocytes has been recently documented using 4D imaging and challenged our current view on protein export in malaria 6. Thus, intravital imaging has radically changed our view on key events in Plasmodium development. Unfortunately, studies of the dynamic passage of malaria parasites through the spleen, a major lymphoid organ exquisitely adapted to clear infected red blood cells are lacking due to technical constraints.
Using the murine model of malaria Plasmodium yoelii in Balb/c mice, we have implemented intravital imaging of the spleen and reported a differential remodeling of it and adherence of parasitized red blood cells (pRBCs) to barrier cells of fibroblastic origin in the red pulp during infection with the non-lethal parasite line P.yoelii 17X as opposed to infections with the P.yoelii 17XL lethal parasite line 7. To reach these conclusions, a specific methodology using ImageJ free software was developed to enable characterization of the fast three-dimensional movement of single-pRBCs. Results obtained with this protocol allow determining velocity, directionality and residence time of parasites in the spleen, all parameters addressing adherence in vivo. In addition, we report the methodology for blood flow quantification using intravital microscopy and the use of different colouring agents to gain insight into the complex microcirculatory structure of the spleen. 
Ethics statement
All the animal studies were performed at the animal facilities of University of Barcelona in accordance with guidelines and protocols approved by the Ethics Committee for Animal Experimentation of the University of Barcelona CEEA-UB (Protocol No DMAH: 5429). Female Balb/c mice of 6-8 weeks of age were obtained from Charles River Laboratories.

We show the method for performing intravital microscopy of the spleen using GFP transgenic malaria parasites and the quantification of parasite mobility and blood flow within this organ.

Microscopia intravital del bazo: Análisis cuantitativo de la movilidad del parásito y el flujo sanguíneo

The advent of intravital microscopy in experimental rodent malaria models has allowed major advances to the knowledge of parasite-host interactions 1,2. ...

Highly Resolved Intravital Striped-illumination Microscopy of Germinal Centers

Monitoring cellular communication by intravital deep-tissue multi-photon microscopy is the key for understanding the fate of immune cells within thick tissue samples and organs in health and disease. By controlling the scanning pattern in multi-photon microscopy and applying appropriate numerical algorithms, we developed a striped-illumination approach, which enabled us to achieve 3-fold better axial resolution and improved signal-to-noise ratio, i.e. contrast, in more than 100 &#181;m tissue depth within highly scattering tissue of lymphoid organs as compared to standard multi-photon microscopy. The acquisition speed as well as photobleaching and photodamage effects were similar to standard photo-multiplier-based technique, whereas the imaging depth was slightly lower due to the use of field detectors. By using the striped-illumination approach, we are able to observe the dynamics of immune complex deposits on secondary follicular dendritic cells &#8211; on the level of a few protein molecules in germinal centers.

High-resolution intravital imaging with enhanced contrast up to 120 &#181;m depth in lymph nodes of adult mice is achieved by spatially modulating the excitation pattern of a multi-focal two-photon microscope. In 100 &#181;m depth we measured resolutions of 487 nm (lateral) and 551 nm (axial), thus circumventing scattering and diffraction limits.

Muy resuelto Microscopía intravital rayas-iluminación de centros germinales

Monitoring cellular communication by intravital deep-tissue multi-photon microscopy is the key for understanding the fate of immune cells within thick ...

Long Term Intravital Multiphoton Microscopy Imaging of Immune Cells in Healthy and Diseased Liver Using CXCR6.Gfp Reporter Mice

Liver inflammation as a response to injury is a highly dynamic process involving the infiltration of distinct subtypes of leukocytes including monocytes, neutrophils, T cell subsets, B cells, natural killer (NK) and NKT cells. Intravital microscopy of the liver for monitoring immune cell migration is particularly challenging due to the high requirements regarding sample preparation and fixation, optical resolution and long-term animal survival. Yet, the dynamics of inflammatory processes as well as cellular interaction studies could provide critical information to better understand the initiation, progression and regression of inflammatory liver disease. Therefore, a highly sensitive and reliable method was established to study migration and cell-cell-interactions of different immune cells in mouse liver over long periods (about 6 hr) by intravital two-photon laser scanning microscopy (TPLSM) in combination with intensive care monitoring.
The method provided includes a gentle preparation and stable fixation of the liver with minimal perturbation of the organ; long term intravital imaging using multicolor multiphoton microscopy with virtually no photobleaching or phototoxic effects over a time period of up to 6 hr, allowing tracking of specific leukocyte subsets; and stable imaging conditions due to extensive monitoring of mouse vital parameters and stabilization of circulation, temperature and gas exchange.
To investigate lymphocyte migration upon liver inflammation CXCR6.gfp knock-in mice were subjected to intravital liver imaging under baseline conditions and after acute and chronic liver damage induced by intraperitoneal injection(s) of carbon tetrachloride (CCl4).
CXCR6 is a chemokine receptor expressed on lymphocytes, mainly on Natural Killer T (NKT)-, Natural Killer (NK)- and subsets of T lymphocytes such as CD4 T cells but also mucosal associated invariant (MAIT) T cells1. Following the migratory pattern and positioning of CXCR6.gfp+ immune cells allowed a detailed insight into their altered behavior upon liver injury and therefore their potential involvement in disease progression.

Stable intravital high-resolution imaging of immune cells in the liver is challenging. Here we provide a highly sensitive and reliable method to study migration and cell-cell-interactions of immune cells in mouse liver over long periods (about 6 hours) by intravital multiphoton laser scanning microscopy in combination with intensive care monitoring.

Largo Plazo intravital Multifotónica de imágenes de microscopía de células inmunitarias en sanos y enfermos de hígado utilizando ratones CXCR6.Gfp Reporter

Liver inflammation as a response to injury is a highly dynamic process involving the infiltration of distinct subtypes of leukocytes including monocytes, ...

Imaging Neutrophils and Monocytes in Mesenteric Veins by Intravital Microscopy on Anaesthetized Mice in Real Time

Efficient immune response is dependent on rapid mobilization of blood leukocytes to the site of infection or injury. Investigating leukocyte migration in vivo is crucial for understanding the molecular basis of leukocyte transendothelial migration and interaction with vascular endothelium. One powerful approach involves intravital microscopy on transgenic mice expressing fluorescent proteins in cells of interest.
Here we present a protocol for imaging monocytes and neutrophils in the CX3CR1gfp/wt mouse i.v. injected with orange dye-labeled neutrophils with an inverted confocal microscope. Time-lapse movies gathered from 30 min&#160;to several hours of imaging allow the analysis of leukocyte behavior in mesenteric veins under both steady state and inflammatory conditions. We also describe the steps to locally induce blood vessel inflammation with TLR2/TLR1 agonist Pam3SK4 and monitor the subsequent recruitment of neutrophils and monocytes.
The presented technique can also be used to monitor other populations of leukocytes and investigate molecules implicated in leukocyte recruitment or trafficking using other stimuli or transgenic mice.

We detail a protocol to monitor the behavior of neutrophils and monocytes in mesenteric veins under steady state and inflammatory conditions using intravital confocal microscopy on anaesthetized mice.

Imaging neutrófilos y monocitos en mesentérica venas por Microscopia intravital en ratones anestesiados en Tiempo Real

Efficient immune response is dependent on rapid mobilization of blood leukocytes to the site of infection or injury. Investigating leukocyte migration in ...

Preparation of Murine Submandibular Salivary Gland for Upright Intravital Microscopy

The submandibular salivary gland (SMG) is one of the three major salivary glands, and is of interest for many different fields of biological research, including cell biology, oncology, dentistry, and immunology. The SMG is an exocrine gland comprised of secretory epithelial cells, myofibroblasts, endothelial cells, nerves, and extracellular matrix. Dynamic cellular processes in the rat and mouse SMG have previously been imaged, mostly using inverted multi-photon microscope systems. Here, we describe a straightforward protocol for the surgical preparation and stabilization of the murine SMG in anesthetized mice for in vivo imaging with upright multi-photon microscope systems. We present representative intravital image sets of endogenous and adoptively transferred fluorescent cells, including the labeling of blood vessels or salivary ducts and second harmonic generation to visualize fibrillar collagen. In sum, our protocol allows for surgical preparation of mouse salivary glands in upright microscopy systems, which are commonly used for intravital imaging in the field of immunology.

We describe a protocol to surgically expose and stabilize the murine submandibular salivary gland for intravital imaging using upright intravital microscopy. This protocol is easily adaptable to other exocrine glands of the head and neck region of mice and other small rodents.

Preparación de glándula salival submaxilar murino para la microscopia Intravital vertical

The submandibular salivary gland (SMG) is one of the three major salivary glands, and is of interest for many different fields of biological research, ...

Imaging Cell Interaction in Tracheal Mucosa During Influenza Virus Infection Using Two-photon Intravital Microscopy

The analysis of cell-cell or cell-pathogen interaction in vivo is an important tool to understand the dynamics of the immune response to infection. Two-photon intravital microscopy (2P-IVM) allows the observation of cell interactions in deep tissue in living animals, while minimizing the photobleaching generated during image acquisition. To date, different models for 2P-IVM of lymphoid and non-lymphoid organs have been described. However, imaging of respiratory organs remains a challenge due to the movement associated with the breathing cycle of the animal.
Here, we describe a protocol to visualize in vivo immune cell interactions in the trachea of mice infected with influenza virus using 2P-IVM. To this purpose, we developed a custom imaging platform, which included the surgical exposure and intubation of the trachea, followed by the acquisition of dynamic images of neutrophils and dendritic cells (DC) in the mucosal epithelium. Additionally, we detailed the steps needed to perform influenza intranasal infection and flow cytometric analysis of immune cells in the trachea. Finally, we analyzed neutrophil and DC motility as well as their interactions during the course of a movie. This protocol allows for the generation of stable and bright 4D images necessary for the assessment of cell-cell interactions in the trachea.

In this study, we present a protocol to perform two-photon intravital imaging and cell interaction analysis in the murine tracheal mucosa after infection with influenza virus. This protocol will be relevant for researchers studying immune cell dynamics during respiratory infections.

Proyección de imagen de interacción de células en Mucosa traqueal durante la infección del Virus de la Influenza usando microscopia Intravital de dos fotones

The analysis of cell-cell or cell-pathogen interaction in vivo is an important tool to understand the dynamics of the immune response to infection. ...

Human Colonoid Monolayers to Study Interactions Between Pathogens, Commensals, and Host Intestinal Epithelium

Human 3-dimensional (3D) enteroid or colonoid cultures derived from crypt base stem cells are currently the most advanced ex vivo model of the intestinal epithelium. Due to their closed structures and significant supporting extracellular matrix, 3D cultures are not ideal for host-pathogen studies. Enteroids or colonoids can be grown as epithelial monolayers on permeable tissue culture membranes to allow manipulation of both luminal and basolateral cell surfaces and accompanying fluids. This enhanced luminal surface accessibility facilitates modeling bacterial-host epithelial interactions such as the mucus-degrading ability of enterohemorrhagic E. coli (EHEC) on colonic epithelium. A method for 3D culture fragmentation, monolayer seeding, and transepithelial electrical resistance (TER) measurements to monitor the progress towards confluency and differentiation are described. Colonoid monolayer differentiation yields secreted mucus that can be studied by the immunofluorescence or immunoblotting techniques. More generally, enteroid or colonoid monolayers enable a physiologically-relevant platform to evaluate specific cell populations that may be targeted by pathogenic or commensal microbiota.

Here, we present a protocol to culture human enteroid or colonoid monolayers that have intact barrier function to study host epithelial-microbiota interactions at the cellular and biochemical level.

Monocapas de Colonoid humano para estudiar las interacciones entre patógenos, comensales y epitelio Intestinal Host

Human 3-dimensional (3D) enteroid or colonoid cultures derived from crypt base stem cells are currently the most advanced ex vivo model of the intestinal ...