Name: in vivo vascular permeability detection in mouse submandibular gland
Uploaded: 2022-08-04T14:00:00
Description: Watch this Scientific Journal Video about In Vivo Vascular Permeability Detection in Mouse Submandibular Gland at JoVE.com

Este estudo foi apoiado pela Fundação Nacional de Ciências Naturais da China (bolsas 31972908, 81991500, 81991502, 81771093 e 81974151) e pela Fundação de Ciências Naturais de Pequim (7202082 de subsídios).

Todos os procedimentos experimentais foram aprovados pelo Comitê de Ética em Pesquisa Animal do Centro de Ciências da Saúde da Universidade de Pequim e cumpriram o Guia para o Cuidado e Uso de Animais de Laboratório (NIH Publication No. 85-23, revisado em 1996). Camundongos machos do tipo selvagem (WT) na faixa etária de 8-10 semanas foram utilizados para o presente estudo. Os animais experimentais foram cuidadosamente tratados para minimizar sua dor e desconforto.
1. Procedimentos...

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S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+dissociation+of+paracellular+permeability+and+transepithelial+electrical+resistance+and+disruption+of+the+apical-basolateral+intramembrane+diffusion+barrier+by+expression+of+a+mutant+tight+junction+membrane+protein.">Functional dissociation of paracellular permeability and transepithelial electrical resistance and disruption of the apical-basolateral intramembrane diffusion barrier by expression of a mutant tight junction membrane protein.</a> The Journal of Cell Biology. 134 (4), 1031-1049 (1996).</li><li>Enis, D. 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R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Loss+of+CD34+leads+to+exacerbated+autoimmune+arthritis+through+increased+vascular+permeability.">Loss of CD34 leads to exacerbated autoimmune arthritis through increased vascular permeability.</a> Journal of Immunology. 184 (3), 1292-1299 (2010).</li><li>Egawa, G., Ono, S., Kabashima, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intravital+Imaging+of+vascular+permeability+by+two-photon+microscopy.">Intravital Imaging of vascular permeability by two-photon microscopy.</a> Methods in Molecular Biology. 2223, 151-157 (2021).</li><li>Vestweber, D., Wessel, F., Nottebaum, A. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Similarities+and+differences+in+the+regulation+of+leukocyte+extravasation+and+vascular+permeability.">Similarities and differences in the regulation of leukocyte extravasation and vascular permeability.</a> Seminars in Immunopathology. 36 (2), 177-192 (2014).</li><li>Schulte, 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=Stabilizing+the+VE-cadherin-catenin+complex+blocks+leukocyte+extravasation+and+vascular+permeability.">Stabilizing the VE-cadherin-catenin complex blocks leukocyte extravasation and vascular permeability.</a> The EMBO Journal. 30 (20), 4157-4170 (2011).</li><li>Uhl, B., 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+novel+experimental+approach+for+in+vivo+analyses+of+the+salivary+gland+microvasculature.">A novel experimental approach for in vivo analyses of the salivary gland microvasculature.</a> Frontiers in Immunology. 11, 604470 (2020).</li></ol>

A manutenção e regulação da função de barreira endotelial são essenciais para a homeostase vascular. As células endoteliais e suas junções intercelulares desempenham um papel crítico na manutenção e controle da integridade vascular12. A força de cisalhamento do fluxo sanguíneo, fatores de crescimento e fatores inflamatórios podem causar alterações na permeabilidade vascular e, assim, participar da ocorrência e desenvolvimento de doenças sistêmicas como hipertensão, diabetes e...

Várias glândulas salivares produzem saliva, que atua principalmente como a primeira linha de defesa contra infecções e ajuda a digestão, desempenhando assim um papel essencial na saúde bucal e geral1. O suprimento de sangue é crucial para a secreção das glândulas salivares, uma vez que fornece constantemente água, eletrólitos e moléculas que formam a saliva primária. A função de barreira endotelial, regulada pelo complexo de junção apertada (TJ), limita estrita e delicadamente a permeação dos capilares, que são altamente permeáveis à água, solutos, proteínas e até mesmo células que se deslocam dos vasos sanguíneos circulantes para os tecidos das glândulas salivares 2,3. Descobrimos anteriormente que a abertura dos TJs endoteliais em resposta a um estímulo colinérgico facilita a secreção salivar, enquanto o comprometimento da função da barreira endotelial está interligado com hipossecreção e infiltração linfocítica nas glândulas submandibulares (SMGs) na síndrome de Sjögren4. Esses dados sugerem que a contribuição da função de barreira endotelial precisa ser prestada atenção suficiente em relação a uma variedade de doenças das glândulas salivares.
Um microscópio de varredura a laser de dois fótons é uma ferramenta poderosa para observar a dinâmica das células no tecido intacto in vivo. Uma das vantagens dessa técnica é que a luz infravermelha próxima (NIR) tem penetração tecidual mais profunda do que a luz visível ou ultravioleta quando os espécimes são excitados pelo NIR e não causa danos evidentes à luz dos tecidos sob condições apropriadas 5,6. De fato, as glândulas salivares são um tecido muito homogêneo e superficial, no qual as células acinares superficiais estão a apenas cerca de 30 μm de distância da superfície da glândula 7,8. Demonstrou-se que a microscopia confocal intravital pode estudar a secreção exócrina e o citoesqueleto de actina em glândulas salivares vivas de camundongos em resolução subcelular8. A microscopia de varredura a laser de dois fótons, no entanto, não só tem a vantagem da microscopia confocal convencional, mas também pode ser usada para detectar tecidos e imagens mais profundos com mais clareza. Aqui, o dextrans marcado por fluorescência, que é frequentemente usado como traçador de permeabilidade paracelular e tem a vantagem de diferentes tamanhos, pode ser usado para testar a magnitude do poro TJ9. No presente estudo, uma técnica intravital de microscopia a laser de dois fótons em tempo real é estabelecida para avaliação in situ da função da barreira endotelial em SMGs de camundongos. Cada etapa de trabalho para detecção de permeabilidade vascular in vivo em SMGs de camundongos é descrita no protocolo atual. Aqui está um exemplo de detecção da função de barreira endotelial no modelo de ligadura do ducto SMG do rato.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>2-photon microscope (TCS-SP8 DIVE)</td>
			<td>Leica, Germany</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>4 kDa FITC-labeled dextran</td>
			<td>Sigma Aldrich</td>
			<td>46944</td>
			<td></td>
		</tr>
		<tr>
			<td>70 kDa rhodamine B-labeled dextran</td>
			<td>Sigma Aldrich</td>
			<td>R9379</td>
			<td></td>
		</tr>
		<tr>
			<td>Blunt tissue separation nickel</td>
			<td>Bejinghuabo Company</td>
			<td>NZW28</td>
			<td></td>
		</tr>
		<tr>
			<td>Depilatory cream</td>
			<td>Veet</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Disposable sterile syringe</td>
			<td>Zhiyu Company</td>
			<td></td>
			<td>1 mL</td>
		</tr>
		<tr>
			<td>Image J software</td>
			<td>National Institutes of Health</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Insulin syringe</td>
			<td>Becton, Dickinson and Company</td>
			<td>0253316</td>
			<td>1 mL</td>
		</tr>
		<tr>
			<td>Leica Application Suite X software</td>
			<td>Leica Microsystems</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Microtubes</td>
			<td>Axygen</td>
			<td>MCT-150-C</td>
			<td>1.5 mL</td>
		</tr>
		<tr>
			<td>Phosphate buffered saline 1x</td>
			<td>Servicebio</td>
			<td>G4207-500</td>
			<td></td>
		</tr>
		<tr>
			<td>Tissue scissors</td>
			<td>Bejinghuabo Company</td>
			<td>M286-05</td>
			<td></td>
		</tr>
		<tr>
			<td>Tribromoethanol</td>
			<td>JITIAN Bio</td>
			<td>JT0781</td>
			<td></td>
		</tr>
	</tbody>
</table>

in vivo vascular permeability detection in mouse submandibular gland

A saliva desempenha um papel importante na saúde oral e geral. A função de barreira endotelial intacta dos vasos sanguíneos permite a secreção de saliva, enquanto a disfunção da barreira endotelial está relacionada a muitos distúrbios secretores das glândulas salivares. O presente protocolo descreve um método de detecção de permeabilidade paracelular in vivo para avaliar a função das junções endoteliais apertadas (TJs) em glândulas submandibulares de camundongos (SMG). Primeiro, dextrans marcado com fluorescência com diferentes pesos moleculares (4 kDa, 40 kDa, ou 70 kDa) foram injetados nas veias angulares de camundongos. Posteriormente, o SMG unilateral foi dissecado e fixado no suporte personalizado sob um microscópio de varredura a laser de dois fótons e, em seguida, as imagens foram capturadas para vasos sanguíneos, ácinos e dutos. Utilizando este método, o vazamento dinâmico em tempo real dos traçadores de diferentes tamanhos dos vasos sanguíneos para os lados basais dos ácinos e até mesmo através do epitélio acinar para os ductos foi monitorado para avaliar a alteração da função de barreira endotelial sob condições fisiológicas ou fisiopatológicas.

Seguindo o protocolo, o SMG unilateral foi anexado a um suporte personalizado, e a glândula foi mantida o mais longe possível do corpo do rato para evitar que a respiração causasse artefatos de movimento. O rápido fluxo dos glóbulos vermelhos (pontos pretos) nos vasos sanguíneos foi observado ao microscópio. Depois de encontrar o campo de tecido sob uma lente ocular, deve-se mudar para manipular o software do microscópio. No grupo controle, ambos os marcadores existiam nos vasos sanguíneos do camundongo SMG. Em...

Watch this Scientific Journal Video about In Vivo Vascular Permeability Detection in Mouse Submandibular Gland at JoVE.com

In Vivo Vascular Permeability Detection in Mouse Submandibular Gland

No presente protocolo, a função de barreira endotelial da glândula submandibular (SMG) foi avaliada por meio da injeção de diferentes marcadores fluorescentes de peso molecular nas veias angulares de modelos animais de teste in vivo sob um microscópio de varredura a laser de dois fótons.

In vivo Detecção de Permeabilidade Vascular em Glândula Submandibular de Camundongo

Saliva plays an important role in oral and overall health. The intact endothelial barrier function of blood vessels enables saliva secretion, whereas the ...

O presente protocolo descreve uma medida de detecção de permeabilidade paracelular in vivo para avaliar a função de junções endoteliais apertadas em glândulas submandibulares de camundongos. A microscopia de varredura a laser de dois fótons, no entanto, não só tem a vantagem da microscopia confocal convencional, mas também pode ser usada para detectar tecidos e imagens mais profundos com mais clareza. Este experimento fornece uma boa medida de método para avaliar a permeabilidade vascular de diferentes tecidos, especialmente os tecidos superficiais e órgãos de animais.Comece escolhendo marcadores apropriados, como fluoresceína, isotiocianato, dextrano marcado e rodamina B, dextran marcado com espectros distintos de emissões de excitação, para minimizar a interferência entre os sinais de fluorescência para o ensaio de permeabilidade. Diluir os vestígios em solução salina tamponada com fosfato estéril em estoques de 100 miligramas por mililitro e armazenar as alíquotas protegidas da luz a menos 20 graus Celsius. Depois de anestesiar o rato macho do tipo selvagem de 8 a 10 semanas de idade, segure suavemente a cabeça e o pescoço do rato para fazer com que um lado do globo ocular se projete ligeiramente.Insira uma seringa de insulina contendo 100 microlitros de mistura de solução de marcador fluorescente ao longo do canto do olho em ângulo reto com o olho. Após a injeção, coloque rapidamente o rato sobre o cartão em decúbito dorsal com os membros e a cabeça adesivados. Para isolamento da glândula submandibular ou SMG, sob um microscópio estereoscópico, corte a epiderme do pescoço com tesouras de tecido geral para expor ambos os lados dos SMGs.Em seguida, use uma agulha de separação de tecido contundente para separar suavemente a cápsula da superfície da glândula sem danificar o tecido da glândula, os vasos sanguíneos e a estrutura glandular. Conecte o suporte personalizado ao dispositivo de pressão negativa e verifique se o efeito de pressão negativa é adequadamente alcançado com antecedência. Coloque suavemente o SMG exposto no suporte personalizado e sugue o tecido por sucção por pressão negativa, o mais longe possível do corpo do rato, para reduzir os artefactos de movimento causados pela respiração e outras condições.Comece a imagem logo após o local da glândula ser escolhido. Adquira imagens sequenciais ao longo do eixo Z a dois mícrons de distância da superfície da glândula até 70 a 140 mícrons no tecido para gerar uma construção tridimensional. Em seguida, adquira imagens de lapso de tempo dos vasos para medir a permeabilidade vascular no SMG.Na caixa de diálogo Explorer, clique em Adicionar Nova Pasta" e altere o nome do arquivo. Em seguida, volte para a coluna de aquisição. Em XY, o formato é de 512 por 512, e a velocidade é de 400 hertz.Ative o X"R bidirecional, defina o fator de zoom como 0,75 e 1,5 para zoom. Em seguida, selecione XYT em Modo de Aquisição "para adquirir imagens de lapso de tempo. Defina a duração para 20 segundos, 30 minutos ou mais, de acordo com a necessidade experimental.Depois de definir as condições, clique em Live"para observar a imagem vascular de dois canais e canais sobrepostos no quadro de formação de fotos e escolha as áreas de interesse. Clique em Iniciar" para iniciar a geração de imagens. Ensaio de permeabilidade vascular in vivo e imagens tridimensionais de vasos sanguíneos em camundongos.As glândulas submandibulares são mostradas aqui. No grupo controle, ambos os marcadores existiam nos vasos sanguíneos do SMG. Devido ao seu pequeno peso molecular, o FD4 foi capaz de vazar dos vasos sanguíneos para os lados basais dos ácinos e ductos, descrevendo assim claramente a forma dos ácinos e ductos.O RD70 foi distribuído em vasos sanguíneos de grande porte e microvasos. No grupo ligadura do ducto, tanto o FD4 quanto o RD70 foram extravasados para os lados basais dos ácinos, o que indicou que a ligadura do ducto poderia interromper a função de barreira endotelial e aumentar a permeabilidade a moléculas grandes. Além disso, os resultados semiquantitativos de intensidade de fluorescência FD4 e RD70 confirmaram essas observações.As imagens tridimensionais mostraram fluorescência muito mais obscurecida de FD4 e RD70 ao redor dos vasos sanguíneos no grupo ligadura em comparação com o grupo controle. O isolamento cuidadoso do SMG e a colocação apropriada e o microscópio são pré-requisitos essenciais para uma detecção bem-sucedida. Após os procedimentos, a taxa de fluxo sanguíneo pode ser calculada casando o movimento dos glóbulos vermelhos e a infiltração das células sanguíneas marcadas com fluorescência pode ser perseguida.

in-vivo-vascular-permeability-detection-in-mouse-submandibular-gland

Research

JoVE Journal

Biology

In Vivo Vascular Permeability Detection in Mouse Submandibular Gland

Single-cell Suction Recordings from Mouse Cone Photoreceptors

Rod and cone photoreceptors in the retina are responsible for light detection. In darkness, cyclic nucleotide-gated (CNG) channels in the outer segment are open and allow cations to flow steadily inwards across the membrane, depolarizing the cell. Light exposure triggers the closure of the CNG channels, blocks the inward cation current flow, and thus results in cell hyperpolarization. Based on the polarity of photoreceptors, a suction recording method was developed in 1970s that, unlike the classic patch-clamp technique, does not require penetrating the plasma membrane 1. Drawing the outer segment into a tightly-fitting glass pipette filled with extracellular solution allows recording the current changes in individual cells upon test-flash exposure. However, this well-established "outer-segment-in (OS-in)" suction recording is not suitable for mouse cone recordings, because of the low percentage of cones in the mouse retina (3%) and the difficulties in identifying the cone outer segments. Recently, an inner-segment-in (IS-in) recording configuration was developed to draw the inner segment/nuclear region of the photoreceptor into the recording pipette 2,3. In this video, we will show how to record from individual mouse cone photoresponses using single-cell suction electrode.

We will show how to record flash responses from single mouse cones using a suction electrode.

Gravações de uma única célula de sucção de cones fotorreceptores rato

Rod and cone photoreceptors in the retina are responsible for light detection. In darkness, cyclic nucleotide-gated (CNG) channels in the outer segment ...

Biologia

In vivo Imaging and Therapeutic Treatments in an Orthotopic Mouse Model of Ovarian Cancer

Human cancer and response to therapy is better represented in orthotopic animal models. This paper describes the development of an orthotopic mouse model of ovarian cancer, treatment of cancer via oral delivery of drugs, and monitoring of tumor cell behavior in response to drug treatment in real time using in vivo imaging system. In this orthotopic model, ovarian tumor cells expressing luciferase are applied topically by injecting them directly into the mouse bursa where each ovary is enclosed. Upon injection of D-luciferin, a substrate of firefly luciferase, luciferase-expressing cells generate bioluminescence signals. This signal is detected by the in vivo imaging system and allows for a non-invasive means of monitoring tumor growth, distribution, and regression in individual animals. Drug administration via oral gavage allows for a maximum dosing volume of 10 mL/kg body weight to be delivered directly to the stomach and closely resembles delivery of drugs in clinical treatments. Therefore, techniques described here, development of an orthotopic mouse model of ovarian cancer, oral delivery of drugs, and in vivo imaging, are useful for better understanding of human ovarian cancer and treatment and will improve targeting this disease.

In vivo Imaging and Therapeutic Treatments in an Orthotopic Mouse Model of Ovarian Cancer

Orthotopic animal models of ovarian cancer replicate better human disease and therefore enhance our understanding of cancer progression and tumor response to therapy. A mouse model receives an intrabursal injection of luciferase-expressing ovarian tumor cells. Treatment is administered via oral gavage. Tumor growth is monitored by in vivo imaging system.

In vivo de imagens e tratamentos terapêuticos em um modelo de camundongo ortotópico de câncer de ovário

Human cancer and response to therapy is better represented in orthotopic animal models.  This paper describes the development of an orthotopic mouse model ...

Isolation of Mouse Salivary Gland Stem Cells

Mature salivary glands of both human and mouse origin comprise a minimum of five cell types, each of which facilitates the production and excretion of saliva into the oral cavity. Serous and mucous acinar cells are the protein and mucous producing factories of the gland respectively, and represent the origin of saliva production. Once synthesised, the various enzymatic and other proteinaceous components of saliva are secreted through a series of ductal cells bearing epithelial-type morphology, until the eventual expulsion of the saliva through one major duct into the cavity of the mouth. The composition of saliva is also modified by the ductal cells during this process.
In the manifestation of diseases such as Sj&ouml;gren's syndrome, and in some clinical situations such as radiotherapy treatment for head and neck cancers, saliva production by the glands is dramatically reduced 1,2. The resulting xerostomia, a subjective feeling of dry mouth, affects not only the ability of the patient to swallow and speak, but also encourages the development of dental caries and can be socially debilitating for the sufferer.
The restoration of saliva production in the above-mentioned clinical conditions therefore represents an unmet clinical need, and as such several studies have demonstrated the regenerative capacity of the salivary glands 3-5. Further to the isolation of stem cell-like populations of cells from various tissues within the mouse and human bodies 6-8, we have shown using the described method that stem cells isolated from mouse salivary glands can be used to rescue saliva production in irradiated salivary glands 9,10. This discovery paves the way for the development of stem cell-based therapies for the treatment of xerostomic conditions in humans, and also for the exploration of the salivary gland as a microenvironment containing cells with multipotent self-renewing capabilities.

An optimized protocol for the isolation of stem cells from the mouse salivary gland is described. The method employs enzymatic and mechanical digestion, and permits isolation of salispheres containing cells with characteristics of stem cells.

Isolamento de Células-Tronco do rato das Glândulas Salivares

Mature salivary glands of both human and mouse origin comprise a minimum of five cell types, each of which facilitates the production and excretion of ...

Evaluation of Mammary Gland Development and Function in Mouse Models

The human mammary gland is composed of 15-20 lobes that secrete milk into a branching duct system opening at the nipple. Those lobes are themselves composed of a number of terminal duct lobular units made of secretory alveoli and converging ducts1. In mice, a similar architecture is observed at pregnancy in which ducts and alveoli are interspersed within the connective tissue stroma. The mouse mammary gland epithelium is a tree like system of ducts composed of two layers of cells, an inner layer of luminal cells surrounded by an outer layer of myoepithelial cells denoted by the confines of a basement membrane2. At birth, only a rudimental ductal tree is present, composed of a primary duct and 15-20 branches. Branch elongation and amplification start at the beginning of puberty, around 4 weeks old, under the influence of hormones3,4,5. At 10 weeks, most of the stroma is invaded by a complex system of ducts that will undergo cycles of branching and regression in each estrous cycle until pregnancy2. At the onset of pregnancy, a second phase of development begins, with the proliferation and differentiation of the epithelium to form grape-shaped milk secretory structures called alveoli6,7. Following parturition and throughout lactation, milk is produced by luminal secretory cells and stored within the lumen of alveoli. Oxytocin release, stimulated by a neural reflex induced by suckling of pups, induces synchronized contractions of the myoepithelial cells around the alveoli and along the ducts, allowing milk to be transported through the ducts to the nipple where it becomes available to the pups 8. Mammary gland development, differentiation and function are tightly orchestrated and require, not only interactions between the stroma and the epithelium, but also between myoepithelial and luminal cells within the epithelium9,10,11. Thereby, mutations in many genes implicated in these interactions may impair either ductal elongation during puberty or alveoli formation during early pregnancy, differentiation during late pregnancy and secretory activation leading to lactation12,13. In this article, we describe how to dissect mouse mammary glands and assess their development using whole mounts. We also demonstrate how to evaluate myoepithelial contractions and milk ejection using an ex-vivo oxytocin-based functional assay. The effect of a gene mutation on mammary gland development and function can thus be determined in situ by performing these two techniques in mutant and wild-type control mice.

This method describes how to dissect and assess mammary gland development and function from mice. Excised mammary glands are assessed for the degree of development using whole mount while milk ejection is evaluated using an oxytocin-based myoepithelial cell contraction assay.

Avaliação do desenvolvimento da glândula mamária e Função em modelos de ratos

The human mammary gland is composed of 15-20 lobes that secrete milk into a branching duct system opening at the nipple. Those lobes are themselves ...

Multi-parameter Measurement of the Permeability Transition Pore Opening in Isolated Mouse Heart Mitochondria

The mitochondrial permeability transition pore (mtPTP) is a non specific channel that forms in the inner mitochondrial membrane to transport solutes with a molecular mass smaller than 1.5 kDa. Although the definitive molecular identity of the pore is still under debate, proteins such as cyclophilin D, VDAC and ANT contribute to mtPTP formation. While the involvement of mtPTP opening in cell death is well established1, accumulating evidence indicates that the mtPTP serves a physiologic role during mitochondrial Ca2+ homeostasis2, bioenergetics and redox signaling 3.
mtPTP opening is triggered by matrix Ca2+ but its activity can be modulated by several other factors such as oxidative stress, adenine nucleotide depletion, high concentrations of Pi, mitochondrial membrane depolarization or uncoupling, and long chain fatty acids4. In vitro, mtPTP opening can be achieved by increasing Ca2+ concentration inside the mitochondrial matrix through exogenous additions of Ca2+ (calcium retention capacity). When Ca2+ levels inside mitochondria reach a certain threshold, the mtPTP opens and facilitates Ca2+ release, dissipation of the proton motive force, membrane potential collapse and an increase in mitochondrial matrix volume (swelling) that ultimately leads to the rupture of the outer mitochondrial membrane and irreversible loss of organelle function.
Here we describe a fluorometric assay that allows for a comprehensive characterization of mtPTP opening in isolated mouse heart mitochondria. The assay involves the simultaneous measurement of 3 mitochondrial parameters that are altered when mtPTP opening occurs: mitochondrial Ca2+ handling (uptake and release, as measured by Ca2+ concentration in the assay medium), mitochondrial membrane potential, and mitochondrial volume. The dyes employed for Ca2+ measurement in the assay medium and mitochondrial membrane potential are Fura FF, a membrane impermeant, ratiometric indicator which undergoes a shift in the excitation wavelength in the presence of Ca2+, and JC-1, a cationic, ratiometric indicator which forms green monomers or red aggregates at low and high membrane potential, respectively. Changes in mitochondrial volume are measured by recording light scattering by the mitochondrial suspension. Since high-quality, functional mitochondria are required for the mtPTP opening assay, we also describe the steps necessary to obtain intact, highly coupled and functional isolated heart mitochondria.

A spectrofluorometric protocol for the measurement of the mitochondrial permeability transition pore opening in isolated mouse heart mitochondria is presented here. The assay involves the simultaneous measurement of mitochondria Ca2+ handling, mitochondrial membrane potential and mitochondrial volume. The procedure for obtaining high-quality and functional heart mitochondria is also described.

Parâmetro Multi-Medição da abertura dos poros transição de permeabilidade em mitocôndrias isoladas de coração Rato

The mitochondrial permeability transition pore (mtPTP) is a non specific channel that forms in the inner mitochondrial membrane to transport solutes with ...

Intraductal Injection for Localized Drug Delivery to the Mouse Mammary Gland

Herein we describe a protocol to deliver various reagents to the mouse mammary gland via intraductal injections. Localized drug delivery and knock-down of genes within the mammary epithelium has been difficult to achieve due to the lack of appropriate targeting molecules that are independent of developmental stages such as pregnancy and lactation. Herein, we describe a technique for localized delivery of reagents to the mammary gland at any stage in adulthood via intraductal injection into the nipples of mice. The injections can be performed on live mice, under anesthesia, and allow for a non-invasive and localized drug delivery to the mammary gland. Furthermore, the injections can be repeated over several months without damaging the nipple. Vital dyes such as Evans Blue are very helpful to learn the technique. Upon intraductal injection of the blue dye, the entire ductal tree becomes visible to the eye. Furthermore, fluorescently labeled reagents also allow for visualization and distribution within the mammary gland. This technique is adaptable for a variety of compounds including siRNA, chemotherapeutic agents, and small molecules.

A protocol for the non-invasive intraductal delivery of aqueous reagents to the mouse mammary gland is described. The method takes advantage of localized injection into the nipples of mammary glands targeting mammary ducts specifically. This technique is adaptable for a variety of compounds including siRNA, chemotherapeutic agents and small molecules.

Injeção Intraductal para localizada Drug Delivery ao Rato glândula mamária

Herein we describe a protocol to deliver various reagents to the mouse mammary gland via intraductal injections. Localized drug delivery and knock-down of ...

Measuring the Osmotic Water Permeability Coefficient (Pf) of Spherical Cells: Isolated Plant Protoplasts as an Example

Studying AQP regulation mechanisms is crucial for the understanding of water relations at both the cellular and the whole plant levels. Presented here is a simple and very efficient method for the determination of the osmotic water permeability coefficient (Pf) in plant protoplasts, applicable in principle also to other spherical cells such as frog oocytes. The first step of the assay is the isolation of protoplasts from the plant tissue of interest by enzymatic digestion into a chamber with an appropriate isotonic solution. The second step consists of an osmotic challenge assay: protoplasts immobilized on the bottom of the chamber are submitted to a constant perfusion starting with an isotonic solution and followed by a hypotonic solution. The cell swelling is video recorded. In the third step, the images are processed offline to yield volume changes, and the time course of the volume changes is correlated with the time course of the change in osmolarity of the chamber perfusion medium, using a curve fitting procedure written in Matlab (the &#8216;PfFit&#8217;), to yield Pf.

Measuring the Osmotic Water Permeability Coefficient Pf of Spherical Cells: Isolated Plant Protoplasts as an Example

Measuring the osmotic water permeability coefficient (Pf) of cells can help understand the regulatory mechanisms of aquaporins (AQPs). Pf determination in spherical plant cell protoplasts presented here involves protoplasts isolation and numerical analysis of their initial rate of volume change as a result of an osmotic challenge during constant bath perfusion.

Medindo o Coeficiente de Permeabilidade osmótica de água (P<sub&gt; F</sub&gt;) De células esféricas: protoplastos planta isolada como um exemplo

Studying AQP regulation mechanisms is crucial for the understanding of water relations at both the cellular and the whole plant levels. Presented here is ...

Measuring the Stiffness of Ex Vivo Mouse Aortas Using Atomic Force Microscopy

Arterial stiffening is a significant risk factor and biomarker for cardiovascular disease and a hallmark of aging. Atomic force microscopy (AFM) is a versatile analytical tool for characterizing viscoelastic mechanical properties for a variety of materials ranging from hard (plastic, glass, metal, etc.) surfaces to cells on any substrate. It has been widely used to measure the stiffness of cells, but less frequently used to measure the stiffness of aortas. In this paper, we will describe the procedures for using AFM in contact mode to measure the ex vivo elastic modulus of unloaded mouse arteries. We describe our procedure for isolation of mouse aortas, and then provide detailed information for the AFM analysis. This includes step-by-step instructions for alignment of the laser beam, calibration of the spring constant and deflection sensitivity of the AFM probe, and acquisition of force curves. We also provide a detailed protocol for data analysis of the force curves.

Measuring the Stiffness of Ex Vivo Mouse Aortas Using Atomic Force Microscopy

We present detailed protocols for isolation of aortas from mouse and measurement of their elastic modulus using atomic force microscopy.

Medindo a rigidez<em&gt; Ex Vivo</em&gt; Mouse aortas Usando Microscopia de Força Atômica

Arterial stiffening is a significant risk factor and biomarker for cardiovascular disease and a hallmark of aging. Atomic force microscopy (AFM) is a ...

In Vivo Detection and Analysis of Rb Protein SUMOylation in Human Cells

The post-translational modifications of proteins are critical for the proper regulation of intracellular signal transduction. Among these modifications, small ubiquitin-related modifier (SUMO) is a ubiquitin-like protein that is covalently attached to the lysine residues of a variety of target proteins to regulate cellular processes, such as gene transcription, DNA repair, protein interaction and degradation, subcellular transport, and signal transduction. The most common approach to detecting protein SUMOylation is based on the expression and purification of recombinant tagged proteins in bacteria, allowing for an in vitro biochemical reaction which is simple and suitable for addressing mechanistic questions. However, due to the complexity of the process of SUMOylation in vivo, it is more challenging to detect and analyze protein SUMOylation in cells, especially when under endogenous conditions. A recent study by the authors of this paper revealed that endogenous retinoblastoma (Rb) protein, a tumor suppressor that is vital to the negative regulation of the cell cycle progression, is specifically SUMOylated at the early G1 phase. This paper describes a protocol for the detection and analysis of Rb SUMOylation under both endogenous and exogenous conditions in human cells. This protocol is appropriate for the phenotypical and functional investigation of the SUMO-modification of Rb, as well as many other SUMO-targeted proteins, in human cells.

In Vivo Detection and Analysis of Rb Protein SUMOylation in Human Cells

Small ubiquitin-related modifier (SUMO) family proteins are conjugated to the lysine residues of target proteins to regulate various cellular processes. This paper describes a protocol for the detection of retinoblastoma (Rb) protein SUMOylation under endogenous and exogenous conditions in human cells.

Na Vivo Detecção e análise de SUMOylation de proteína Rb em células humanas

The post-translational modifications of proteins are critical for the proper regulation of intracellular signal transduction. Among these modifications, ...

In Vitro and In Vivo Approaches to Determine Intestinal Epithelial Cell Permeability

The intestinal barrier defends against pathogenic microorganism and microbial toxin. Its function is regulated by tight junction permeability and epithelial cell integrity, and disruption of the intestinal barrier function contributes to progression of gastrointestinal and systemic disease. Two simple methods are described here to measure the permeability of intestinal epithelium. In vitro, Caco-2BBe cells are plated in tissue culture wells as a monolayer and transepithelial electrical resistance (TER) can be measured by an epithelial (volt/ohm) meter. This method is convincing because of its user-friendly operation and repeatability. In vivo, mice are gavaged with 4 kDa fluorescein isothiocyanate (FITC)-dextran, and the FITC-dextran concentrations are measured in collected serum samples from mice to determine the epithelial permeability. Oral gavage provides an accurate dose, and therefore is the preferred method to measure the intestinal permeability in vivo. Taken together, these two methods can measure the permeability of the intestinal epithelium in vitro and in vivo, and hence be used to study the connection between diseases and barrier function.

In Vitro and In Vivo Approaches to Determine Intestinal Epithelial Cell Permeability

Two methods are presented here to determine intestinal barrier function. An epithelial meter (volt/ohm) is used for measurements of transepithelial electrical resistance of cultured epithelia directly in tissue culture wells. In mice, the FITC-dextran gavage method is used to determine the intestinal permeability in vivo.