Este trabalho foi parcialmente financiado pelo NIH RO1-EY019951 (AAF), Illinois Sociedade para a Prevenção da Cegueira (JCC, AAF), fundos irrestrito ao Departamento de Oftalmologia da investigação para prevenir a cegueira (RPB), NY e RPB Medical Student Fellowship Grant (JCC).

1. Preparação da retina <ol><li> Enuclear o olho mouse. Usando um lado, abrir as pálpebras para que o olho é visível. Com a outra mão, usando uma pinça curva (curvas virada para cima), aplicar pressão sobre aspectos superior e inferior da órbita até que se projeta globo. Com cuidado, feche fórceps no aspecto posterior do olho e levante em um movimento contínuo para enuclear o olho. </li><li> Corrigir olhos com 10% de formalina tamponada neutra por pelo menos 24 horas. </li><li> Lugar olho em solução PBS em uma pequena placa de Petri. </li><li> Dissecar retina cuidadosamente sob um microscópio, tendo o cuidado de evitar induzir grandes lágrimas. Faça um corte inicial na córnea com uma tesoura de dissecção. Em seguida, mantendo a área de corte com uma pinça reta, use uma tesoura para cortar ao longo da fronteira da córnea e esclera remoção da córnea. Usando pinça fina curvas e retas, cuidadosamente descascar a esclera e coróide longe da retina para o nervo óptico. Esta etapa exige paciência,libertando rapidamente a retina pode levar às lágrimas. Remover a lente e qualquer excesso de detritos da íris e a retina 16. </li></ol> 2. A água lava <ol><li> Ponto retina num prato de 24 cavidades e cobrir com água (aproximadamente 500 mL, filtrado com pelo menos um filtro de 45 mm). </li><li> Troque a água a cada 30 min-1 hora, pelo menos 4-5 vezes. </li><li> Deixe durante a noite em água com agitação suave à temperatura ambiente. </li></ol> Nota: Os passos de lavagem são muito importantes, pois ajudam a separar as camadas da retina neural a partir dos vasos sanguíneos. 3. Tripsina Digest <ol><li> Remover a água e retina incubar numa solução de 3% de tripsina (Difco 1:250) em tampão Tris 0,1 M (pH 7,8) a 37 ° C com agitação suave para não. Tripsina digestão é completado quando o tecido começa a exibir sinais de desintegração (aproximadamente 1,5 horas). Nota: Evite agitação rápidapois isso pode danificar a vasculatura. </li><li> Cuidadosamente, pipetar a tripsina em separado bem usando um microscópio para evitar tocar a retina. Este excesso de tripsina pode ser usado mais tarde, quando manipular os navios sob o microscópio, no passo 4.3. </li></ol> 4. Separar a vasculatura <ol><li> Adicionar água filtrada para a retina. Em seguida, tentar descolar a membrana limitante interna com uma pinça, usando uma tesoura, se necessário. Agite com agitação suave durante 5 min. Cuidadosamente, pipeta a água sob o microscópio para evitar danificar a retina. </li><li> Repita lavagens com água (por 5 min cada) para ajudar a libertar a rede de vasos do tecido da retina aderente. Lavagens de água são completados quando existe pouca ou nenhuma detritos remanescentes na água após a lavagem. </li><li> Manipulações cuidadosas sob um microscópio de dissecação são agora necessários para liberar ainda mais a rede de vasos. Estes são várias técnicas úteis, que podem ser usados ​​em sequência ou individually para atingir o resultado desejado com base na preferência do técnico: <ol class="lalpha"><li> Usando uma pipeta de 200 mL, pipetar cuidadosamente água para cima e para baixo ao lado de vasos, soprando água em vasos, causando agitação suave. </li><li> Usando uma pipeta de 200 mL, pipeta a tripsina cima e para baixo para ajudar paredes casaco da pipeta. Então, com cuidado pipeta toda a rede de vasos cima e para baixo uma vez para ajudar a quebrar tecido não vascular. Nota: centragem da ponta da pipeta no nervo óptico, em vez de as bordas da rede vascular pode também prevenir a vascularização de furar a ponta. </li><li> Levante cuidadosamente vasculatura com uma pinça fina de água para desalojar os componentes não-vasculares. </li><li> Se as etapas acima não funcionarem, adicione tripsina para a retina para ajudar a quebrar o tecido, e incubar a 37 ° C por alguns minutos. Em seguida, retire de tripsina e repita os passos de 4,1-4,3. </li></ol></li></ol> &lt;strong&gt; Nota: Certifique-se de casaco de todos os instrumentos que entrarão em contato com os vasos em tripsina (por exemplo, a ponta da pipeta, fórceps). Isto irá ajudar a evitar a adesão da vasculatura para o equipamento. 5. Visualizando a vasculatura <ol><li> Colocar uma gota de água sobre uma lâmina de limpeza. Usando uma pipeta ou uma pinça 200 ul, transferir os vasos digeridos na água. Verifique se o plano de montagem vascular é desdobrada. A tensão superficial da água ajuda a desdobrar a rede vascular agora diáfano. Se o tecido não se desdobra, adicione mais água e agitar suavemente a lâmina para facilitar desdobramento. </li><li> Retire o excesso de água muito lentamente por pipetagem ou usando uma toalha de papel. </li><li> Deixar as lâminas para secar completamente. </li><li> Mancha lâminas via protocolo apropriado tanto com PAS / Hematoxilina ou H &amp; E mancha. Nota: PAS / hematoxilina é útil para a identificação da parede do vaso e núcleos celulares, H &amp; E é útil para o demonstration de RBC bem. </li><li> Desidratar e montar (Permount meio de montagem). </li></ol>

<ol>
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A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+procedures+for+isolating+intact+retinal+vascular+beds+from+diabetic+humans+and+animal+models.">Novel procedures for isolating intact retinal vascular beds from diabetic humans and animal models.</a> Invest. Ophthalmol. Vis. Sci. 34, 2097-2104 (1993).</li><li>Midena, E., 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=Studies+on+the+retina+of+the+diabetic+db/db+mouse.+I.+Endothelial+cell-pericyte+ratio.">Studies on the retina of the diabetic db/db mouse. I. 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G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Retinovascular+physiology+and+pathophysiology:+new+experimental+approach/new+insights.">Retinovascular physiology and pathophysiology: new experimental approach/new insights.</a> Prog. Retin. Eye Res. 31, 258-270 (2012).</li><li>Roy, S., Nasser, S., Yee, M., Graves, D. T., Roy, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+long-term+siRNA+strategy+regulates+fibronectin+overexpression+and+improves+vascular+lesions+in+retinas+of+diabetic+rats.">A long-term siRNA strategy regulates fibronectin overexpression and improves vascular lesions in retinas of diabetic rats.</a> Mol. Vis. 17, 3166-3174 (2011).</li><li>Li, Q., 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=Diabetic+eNOS-knockout+mice+develop+accelerated+retinopathy.">Diabetic eNOS-knockout mice develop accelerated retinopathy.</a> Invest. Ophthalmol. Vis. Sci. 51, 5240-5246 (2010).</li><li>Connor, K. M., 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=Quantification+of+oxygen-induced+retinopathy+in+the+mouse:+a+model+of+vessel+loss,+vessel+regrowth+and+pathological+angiogenesis.">Quantification of oxygen-induced retinopathy in the mouse: a model of vessel loss, vessel regrowth and pathological angiogenesis.</a> Nature Protocols. 4, 1565-1573 (2009).</li></ol>

Os autores declaram que não têm interesses financeiros concorrentes.

Tripsina digest é um método padrão para avaliar a vasculatura da retina. Infelizmente, não é tecnicamente difícil e pode resultar numa elevada taxa de perda de amostra se não for realizado correctamente. Além disso, o procedimento é especialmente difícil, em ratos, o que pode limitar a aplicação desta técnica, os modelos animais genéticos usados ​​de doenças oculares. Este documento fornece orientação sobre como realizar o procedimento de forma eficaz e consistente no rato olhos. <p class="jove_...

A visualização da vascularização da retina é uma abordagem extremamente importante para dissecar os mecanismos de várias doenças oculares, tais como retinopatia diabética. Ele permite avaliar as anomalias vasculares, incluindo primeiros microaneurismas, degeneração e perda capilar, pericyte 8,9. Até à data, tem havido várias técnicas desenvolvidas para analisar a vascularização da retina. Perfusão de vários corantes foi utilizada para realçar os vasos, mas todos têm partilhado limitações semelhantes. Injeção raramente destaca toda a vascularização da retina, a menos dado a uma pressão elevada, o que corre o risco de se romper e danificar os vasos 1. Imunocoloração do endotélio vascular com fluorophore marcado G isolectin B4 (Alexa Fluor 594 conjugado; I21413; Invitrogen; 1:100) e monta plano de retina pode-se destacar a arquitetura geral dos vasos, mas sem visualização detalhada dos capilares, membranas basais e pericitos . Foi notada pelosFriedenwald que os navios podem ser destacados pela coloração plana montagens de retina com ácido periódico de Schiff (PAS) ou hematoxilina e eosina (H &amp; E) coloração 10. No entanto, a coloração não foi específico para os vasos e destacada do tecido não-vascular, bem como, o que torna difícil a diferenciação dos vasos. Na década de 1960, Cogan e Kuwabara desenvolveu a técnica digest tripsina que tornou mais fácil a visualização da vascularização da retina através da digestão dos componentes não-vasculares da retina 1. Desde essa altura, a tripsina digest tornou-se o método padrão de ouro na análise da vasculatura da retina 2-5. No entanto, é importante notar que outras técnicas alternativas para isolar a vasculatura tenham sido descritas. A utilização de lise osmótica foi usado para isolar a vasculatura e permitir estudos bioquímicos do tecido 11,12, mas o procedimento não tem sido utilizada como um método primário para estudo anatómicos. O método de impressão de tecidos tem sidousado para isolar grandes segmentos da microvasculatura e permite a possibilidade de estudar a arquitectura electrotonic da vasculatura 13. Em teoria, esta técnica também pode ser usada para estudar alterações anatómicas, como a qualidade dos vasos é elevado. No entanto, só é capaz de isolar segmentos de toda a rede vascular. Embora estes métodos não podem substituir a tripsina digest, é importante notar que eles têm diferentes vantagens e desvantagens e são complementares a este respeito. O método digest tripsina é tecnicamente desafiador e é difícil de executar de forma consistente 6,7. Além disso, tem sido observado que a tripsina digest é especialmente difícil num modelo de ratinho, especialmente se se deseja preservar a arquitectura global vascular da retina 6,7. Os desafios incluem (1) sobre-digestão da retina que provoca a perda de ambas a vasculatura, bem como do tecido não-vascular, (2) sub-digestão, requerendoextensa dissecção mecânica que poderia levar a danos do leito do navio, (3) separação deficiente do tecido não vascular a partir da vasculatura levando a coloração não específica. Vários manuscritos têm destacado estes desafios, mas nenhum deles forneceu um protocolo detalhado e consistente para superá-los 14,15. Este manuscrito irá introduzir uma metodologia passo a passo detalhando a técnica para realizar a digestão da tripsina no rato e rato retinas com dicas específicas sobre o tratamento das etapas particularmente difíceis. Um esquema geral é mostrado na Figura 1.

<table border="1">
	<tbody>
		<tr>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>REAGENTS</td>
		</tr>
		<tr>
			<td>10% neutral buffered formalin</td>
			<td>Fischer Scientific</td>
			<td>SF100-4</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Trypsin (1:250)</td>
			<td>Amresco</td>
			<td>0458-50G</td>
			<td>Make 3% trypsin in 0.1 M Tris</td>
		</tr>
		<tr>
			<td>TRIZMA base</td>
			<td>Sigma</td>
			<td>T1503-1KG</td>
			<td>Create 0.1 M Tris Buffer (pH 7.8 @ 37 &deg;C)</td>
		</tr>
		<tr>
			<td>TRIZMA</td>
			<td>Sigma</td>
			<td>T3253-500G</td>
		</tr>
		<tr>
			<td>Steritop sterile vacuum bottle</td>
			<td>Millipore</td>
			<td>SCGPS05RE</td>
			<td>Create filtered water</td>
		</tr>
		<tr>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>EQUIPMENT</td>
		</tr>
		<tr>
			<td>Dissecting microscope</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>Any microscope that allows good visualization of the retina is adequate. (10x is sufficient with working distance of 24 mm)</td>
		</tr>
		<tr>
			<td>Straight scissors</td>
			<td>Fine Science Tools</td>
			<td>15024-10</td>
			<td>Cutting edge: 8 mm; Tip diameter: 0.2 mm; 10 cm</td>
		</tr>
		<tr>
			<td>Straight Forceps (Inox)</td>
			<td>Dumont #5</td>
			<td>11252-20</td>
			<td>Biologie tip; 0.05 x 0.02 mm; 11 cm</td>
		</tr>
		<tr>
			<td>Curved Forcepts (Dumostar)</td>
			<td>Dumont #7</td>
			<td>11297-10</td>
			<td>Biologie tip; 0.07 x 0.04 mm; 11.5 cm</td>
		</tr>
		<tr>
			<td>Dubnoff Metabolic Shaker Incubator</td>
			<td>Precision Scientific</td>
			<td>BDG59442</td>
			<td>Shaker optional</td>
		</tr>
		<tr>
			<td>24-well dish</td>
			<td>Falcon</td>
			<td>353047</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Microscope Slides</td>
			<td>VWR</td>
			<td>82027-132</td>
			<td>&nbsp;</td>
		</tr>
	</tbody>
</table>

trypsin digest protocol to analyze the retinal vasculature of a mouse model

Tripsina digest é o método padrão de ouro para analisar a vasculatura retiniana 1-5. Ela permite a visualização de toda a rede de vasos complexas tridimensionais retina sanguíneos e capilares, criando um bidimensional plana de montagem dos canais vasculares interligados após digestão dos componentes não-vasculares da retina. Isto permite estudar várias alterações patológicas vasculares, tais como a degeneração capilar, microaneurismas, e anormal endoteliais rácios pericyte. No entanto, o método é tecnicamente difícil, especialmente em ratos, que se tenham tornado o modelo animal mais amplamente disponíveis para estudar a retina por causa da facilidade de manipulações genéticas 6,7. No olho do rato, é particularmente difícil de remover completamente os componentes não-vasculares, mantendo a arquitectura geral dos vasos sanguíneos da retina. Até o momento, há uma escassez de literatura que descreve a técnica de digestão de tripsina em detalhe in o mouse. Este manuscrito fornece uma metodologia detalhada passo-a-passo da tripsina digest no rato retina, além de fornecer dicas sobre solução de problemas etapas difíceis.

O produto final de um processo bem sucedido é um plano de montagem de toda a rede da vasculatura da retina do rato, com a arquitectura mantida, coradas quer com PAS / hematoxilina ou H &amp; E, tal como mostrado nas Figuras 2-4. Limpar a diferenciação das células endoteliais e pericitos pode ser visto como mostrado na Figura 3. Na retina, os núcleos das células endoteliais são ovais ou alongadas e ficar inteiramente dentro da parede do vaso. Pericyte núcleos são pequenos, esfé...

Watch this Scientific Journal Video about Trypsin Digest Protocol to Analyze the Retinal Vasculature of a Mouse Model at JoVE.com

Trypsin Digest Protocol to Analyze the Retinal Vasculature of a Mouse Model

A tripsina é uma compilação dos métodos mais utilizados para analisar a vasculatura retiniana. Este manuscrito descreve o método em detalhes, incluindo alterações importantes para otimizar a técnica e remover o tecido não-vascular, preservando a arquitetura geral dos vasos.

Tripsina Digest protocolo para analisar a vascularização da retina de um rato modelo

Trypsin digest is the gold standard method to analyze the retinal vasculature 1-5. It allows visualization of the entire network of complex ...

trypsin-digest-protocol-to-analyze-retinal-vasculature-mouse

Research

JoVE Journal

Neuroscience

18.2K visualizações.  Northwestern University Feinberg School of Medicine. A tripsina é uma compilação dos métodos mais utilizados para analisar a vasculatura retiniana. Este manuscrito descreve o método em detalhes, incluindo alterações importantes para otimizar a técnica e remover o tecido não-vascular, preservando a arquitetura geral dos vasos.

Vídeo: Trypsin Digest Protocol to Analyze the Retinal Vasculature of a Mouse Model

Patch Clamp Recordings from Mouse Retinal Neurons in a Dark-adapted Slice Preparation

Our visual experience is initiated when the visual pigment in our retinal photoreceptors absorbs photons of light energy and initiates a cascade of intracellular events that lead to closure of cyclic-nucleotide-gated channels in the cell membrane. The resulting change in membrane potential leads in turn to reductions in the amount of neurotransmitter release from both rod and cone synaptic terminals. To measure how the light-evoked change in photoreceptor membrane potential leads to downstream activity in the retina, scientists have made electrophysiological recordings from retinal slice preparations for decades1,2. In the past these slices have been cut manually with a razor blade on retinal tissue that is attached to filter paper; in recent years another method of slicing has been developed whereby retinal tissue is embedded in low gelling temperature agar and sliced in cool solution with a vibrating microtome3,4. This preparation produces retinal slices with less surface damage and very robust light-evoked responses. Here we document how this procedure can be done under infrared light to avoid bleaching the visual pigment.

Here we describe a procedure for generating dark-adapted slices of the mouse retina for electrophysiological recordings.

Remendo Recordings Grampo de neurônios da retina do rato em um Preparação Slice Dark-adaptados

Our visual experience is initiated when the visual pigment in our retinal photoreceptors absorbs photons of light energy and initiates a cascade of ...

Neurociência

Dissection of a Mouse Eye for a Whole Mount of the Retinal Pigment Epithelium

The retinal pigment epithelium (RPE) lies at the back of the mammalian eye, just under the neural retina, which contains the photoreceptors (rods and cones). The RPE is a monolayer of pigmented cuboidal cells and associates closely with the neural retina just above it. This association makes the RPE of great interest to researchers studying retinal diseases. The RPE is also the site of an in vivo assay of homology-directed DNA repair, the pun assay. The mouse eye is particularly difficult to dissect due to its small size (about 3.5mm in diameter) and its spherical shape. This article demonstrates in detail a procedure for dissection of the eye resulting in a whole mount of the RPE. In this procedure, we show how to work with, rather than against, the spherical structure of the eye. Briefly, the connective tissue, muscle, and optic nerve are removed from the back of the eye. Then, the cornea and lens are removed. Next, strategic cuts are made that result in significant flattening of the remaining tissue. Finally, the neural retina is gently lifted off, revealing an intact RPE, which is still attached to the underlying choroid and sclera. This whole mount can be used to perform the pun assay or for immunohistochemistry or immunofluorescent assessment of the RPE tissue.

A formal demonstration of the dissection of a mouse eye, resulting in a whole mount of the retinal pigment epithelium.

Dissecação de um olho do rato para um monte inteiro do epitélio pigmentar da retina

The retinal pigment epithelium (RPE) lies at the back of the mammalian eye, just under the neural retina, which contains the photoreceptors (rods and ...

An Optic Nerve Crush Injury Murine Model to Study Retinal Ganglion Cell Survival

Injury to the optic nerve can lead to axonal degeneration, followed by a gradual death of retinal ganglion cells (RGCs), which results in irreversible vision loss. Examples of such diseases in human include traumatic optic neuropathy and optic nerve degeneration in glaucoma. It is characterized by typical changes in the optic nerve head, progressive optic nerve degeneration, and loss of retinal ganglion cells, if uncontrolled, leading to vision loss and blindness.
The optic nerve crush (ONC) injury mouse model is an important experimental disease model for traumatic optic neuropathy, glaucoma, etc. In this model, the crush injury to the optic nerve leads to gradual retinal ganglion cells apoptosis. This disease model can be used to study the general processes and mechanisms of neuronal death and survival, which is essential for the development of therapeutic measures. In addition, pharmacological and molecular approaches can be used in this model to identify and test potential therapeutic reagents to treat different types of optic neuropathy.
Here, we provide a step by step demonstration of (I) Baseline retrograde labeling of retinal ganglion cells (RGCs) at day 1, (II) Optic nerve crush injury at day 4, (III) Harvest the retinae and analyze RGC survival at day 11, and (IV) Representative result.

This protocol shows how to retrogradely label retinal ganglion cells, and how to subsequently make an optic nerve crush injury in order to analyze retinal ganglion cell survival and apoptosis. It is an experimental disease model for different types of optic neuropathy, including glaucoma.

Nervo Óptico um modelo murino de lesão por esmagamento Estudo de Sobrevivência de células da retina Gânglio

Injury to the optic nerve can lead to axonal degeneration, followed by a gradual death of retinal ganglion cells (RGCs), which results in irreversible ...

Morphometric Analyses of Retinal Sections

Morphometric analyses of retinal sections have been used in examining retinal diseases. For examples, neuronal cells were significantly lost in the retinal ganglion cell layer (RGCL) in rat models with N-methyl-D-aspartate (NMDA)&#x2013;induced excitotoxicity1, retinal ischemia-reperfusion injury2 and glaucoma3. Reduction of INL and inner plexiform layer (IPL) thicknesses were reversed with citicoline treatment in rats' eyes subjected to kainic acid-mediated glutamate excitotoxicity4. Alteration of RGC density and soma sizes were observed with different drug treatments in eyes with elevated intraocular pressure3,5,6. Therefore, having objective methods of analyzing the retinal morphometries may be of great significance in evaluating retinal pathologies and the effectiveness of therapeutic strategies.
The retinal structure is multi-layers and several different kinds of neurons exist in the retina. The morphometric parameters of retina such as cell number, cell size and thickness of different layers are more complex than the cell culture system. Early on, these parameters can be detected using other commercial imaging software. The values are normally of relative value, and changing to the precise value may need further accurate calculation. Also, the tracing of the cell size and morphology may not be accurate and sensitive enough for statistic analysis, especially in the chronic glaucoma model. The measurements used in this protocol provided a more precise and easy way. And the absolute length of the line and size of the cell can be reported directly and easy to be copied to other files. For example, we traced the margin of the inner and outer most nuclei in the INL and formed a line then using the software to draw a 90 degree angle to measure the thickness. While without the help of the software, the line maybe oblique and the changing of retinal thickness may not be repeatable among individual observers. In addition, the number and density of RGCs can also be quantified. This protocol successfully decreases the variability in quantitating features of the retina, increases the sensitivity in detecting minimal changes.
 	This video will demonstrate three types of morphometric analyses of the retinal sections. They include measuring the INL thickness, quantifying the number of RGCs and measuring the sizes of RGCs in absolute value. These three analyses are carried out with Stereo Investigator (MBF Bioscience &mdash; MicroBrightField, Inc.). The technique can offer a simple but scientific platform for morphometric analyses.

This video demonstrates three types of morphometric analyses of the retina, which include measuring the inner nuclear layer thickness, quantifying the number of retinal ganglion cells (RGCs) and measuring the sizes of RGCs. The technique can offer a simple but scientific platform for morphometric analyses.

Análises morfométricas de secções da retina

Morphometric analyses of retinal sections have been used in examining retinal diseases. For examples, neuronal cells were significantly lost in the ...

A Visual Description of the Dissection of the Cerebral Surface Vasculature and Associated Meninges and the Choroid Plexus from Rat Brain

This video presentation was created to show a method of harvesting the two most important highly vascular structures, not residing within the brain proper, that support forebrain function. They are the cerebral surface (superficial) vasculature along with associated meninges (MAV) and the choroid plexus which are necessary for cerebral blood flow and cerebrospinal fluid (CSF) homeostasis. The tissue harvested is suitable for biochemical and physiological analysis, and the MAV has been shown to be sensitive to damage produced by amphetamine and hyperthermia 1,2. As well, the major and minor cerebral vasculatures harvested in MAV are of potentially high interest when investigating concussive types of head trauma. The MAV dissected in this presentation consists of the pial and some of the arachnoid membrane (less dura) of the meninges and the major and minor cerebral surface vasculature. The choroid plexus dissected is the structure that resides in the lateral ventricles as described by Oldfield and McKinley3,4,5,6. The methods used for harvesting these two tissues also facilitate the harvesting of regional cortical tissue devoid of meninges and larger cerebral surface vasculature, and is compatible with harvesting other brain tissues such as striatum, hypothalamus, hippocampus, etc. The dissection of the two tissues takes from 5 to 10 min total. The gene expression levels for the dissected MAV and choroid plexus, as shown and described in this presentation can be found at GSE23093 (MAV) and GSE29733 (choroid plexus) at the NCBI GEO repository. This data has been, and is being, used to help further understand the functioning of the MAV and choroid plexus and how neurotoxic events such as severe hyperthermia and AMPH adversely affect their function.

This video presentation shows a method of harvesting the two most important highly vascular structures that support forebrain function. They are the cerebral surface (superficial) vasculature along with associated meninges (MAV) and the choroid plexus which are necessary for cerebral blood flow and cerebrospinal fluid (CSF) homeostasis.

A descrição visual do Dissecção da vasculatura cerebral Superfície e Meninges Associados e plexo coróide do cérebro de um rato

This video presentation was created to show a method of harvesting the two most important highly vascular structures, not residing within the brain ...

Implementing Dynamic Clamp with Synaptic and Artificial Conductances in Mouse Retinal Ganglion Cells

Ganglion cells are the output neurons of the retina and their activity reflects the integration of multiple synaptic inputs arising from specific neural circuits. Patch clamp techniques, in voltage clamp and current clamp configurations, are commonly used to study the physiological properties of neurons and to characterize their synaptic inputs. Although the application of these techniques is highly informative, they pose various limitations. For example, it is difficult to quantify how the precise interactions of excitatory and inhibitory inputs determine response output. To address this issue, we used a modified current clamp technique, dynamic clamp, also called conductance clamp 1, 2, 3 and examined the impact of excitatory and inhibitory synaptic inputs on neuronal excitability. This technique requires the injection of current into the cell and is dependent on the real-time feedback of its membrane potential at that time. The injected current is calculated from predetermined excitatory and inhibitory synaptic conductances, their reversal potentials and the cell's instantaneous membrane potential. Details on the experimental procedures, patch clamping cells to achieve a whole-cell configuration and employment of the dynamic clamp technique are illustrated in this video article. Here, we show the responses of mouse retinal ganglion cells to various conductance waveforms obtained from physiological experiments in control conditions or in the presence of drugs. Furthermore, we show the use of artificial excitatory and inhibitory conductances generated using alpha functions to investigate the responses of the cells.

This video article illustrates the set-up, the procedures to patch cell bodies and how to implement dynamic clamp recordings from ganglion cells in whole-mount mouse retinae. This technique allows the investigation of the precise contribution of excitatory and inhibitory synaptic inputs, and their relative magnitude and timing to neuronal spiking.

Implementação da braçadeira dinâmico com Condutâncias Synaptic e Artificial em células ganglionares da retina do rato

Ganglion cells are the output neurons of the  retina and their activity reflects the integration of multiple synaptic inputs  arising from specific neural ...

Video Imaging and Spatiotemporal Maps to Analyze Gastrointestinal Motility in Mice

The enteric nervous system (ENS) plays an important role in regulating gastrointestinal (GI) motility and can function independently of the central nervous system. Changes in ENS function are a major cause of GI symptoms and disease and may contribute to GI symptoms reported in neuropsychiatric disorders including autism. It is well established that isolated colon segments generate spontaneous, rhythmic contractions known as Colonic Migrating Motor Complexes (CMMCs). A procedure to analyze the enteric neural regulation of CMMCs in ex vivo preparations of mouse colon is described. The colon is dissected from the animal and flushed to remove fecal content prior to being cannulated in an organ bath. Data is acquired via a video camera positioned above the organ bath and converted to high-resolution spatiotemporal maps via an in-house software package. Using this technique, baseline contractile patterns and pharmacological effects on ENS function in colon segments can be compared over 3-4 hr. In addition, propagation length and speed of CMMCs can be recorded as well as changes in gut diameter and contraction frequency. This technique is useful for characterizing gastrointestinal motility patterns in transgenic mouse models (and in other species including rat and guinea pig). In this way, pharmacologically induced changes in CMMCs are recorded in wild type mice and in the Neuroligin-3R451C mouse model of autism. Furthermore, this technique can be applied to other regions of the GI tract including the duodenum, jejunum and ileum and at different developmental ages in mice.

This article describes a video imaging technique and high-resolution spatiotemporal mapping to identify changes in the neural regulation of colonic motility in adult mice. Subtle effects on gastrointestinal (GI) function can be detected using this approach in isolated tissue preparations to advance our understanding of GI disease.

Vídeo Imagem e Mapas espaço-temporais para analisar Motilidade Gastrointestinal em Ratos

The enteric nervous system (ENS) plays an important role in regulating gastrointestinal (GI) motility and can function independently of the central ...

Protocol for Isolating the Mouse Circle of Willis

The cerebral arterial circle (circulus arteriosus cerebri) or circle of Willis (CoW) is a circulatory anastomosis surrounding the optic chiasma and hypothalamus that supplies blood to the brain and surrounding structures. It has been implicated in several cerebrovascular disorders, including cerebral amyloid angiopathy (CAA)-associated vasculopathies, intracranial atherosclerosis and intracranial aneurysms. Studies of the molecular mechanisms underlying these diseases for the identification of novel drug targets for their prevention require animal models. Some of these models may be transgenic, whereas others will involve isolation of the cerebro-vasculature, including the CoW.The method described here is suitable for CoW isolation in any mouse lineage and has considerable potential for screening (expression of genes, protein production, posttranslational protein modifications, secretome analysis, etc.) studies on the large vessels of the mouse cerebro-vasculature. It can also be used for ex vivo studies, by adapting the organ bath system developed for isolated mouse olfactory arteries.

We describe here a reproducible protocol for isolating the mouse circle of Willis.

Protocolo para isolar o mouse Círculo de Willis

The cerebral arterial circle (circulus arteriosus cerebri) or circle of Willis (CoW) is a circulatory anastomosis surrounding the optic chiasma and ...

Preparation of Mouse Retinal Cryo-sections for Immunohistochemistry

Preparation of high-quality mouse eye sections for immunohistochemistry (IHC) is critical for assessing the retinal structure and function and for determining the mechanisms underlying retinal diseases. Maintaining structural integrity throughout the tissue preparation is vital for obtaining reproducible retinal IHC data but can be challenging due to the fragility and complexity of retinal cytoarchitecture. Strong fixatives like 10% formalin or Bouin's solution optimally preserve the retinal structure, they often impede IHC analysis by enhancing the background fluorescence and/or diminishing antibody-epitope interactions, a process known as epitope masking. Milder fixatives, on the other hand, like 4% paraformaldehyde, reduces background fluorescence and epitope-masking, meticulous dissection techniques must be utilized to preserve the retinal structure. In this article, we present a comprehensive method to prepare mouse ocular posterior cups for IHC that is sufficient to preserve most antibody-epitope interactions without loss of retinal structural integrity. We include representative IHC with antibodies to various retinal cell type markers to illustrate tissue preservation and orientation under optimal and sub-optimal conditions. Our goal is to optimize IHC studies of the retina by providing a complete protocol from ocular posterior cup dissection to IHC.

This report describes comprehensive methods for preparing frozen mouse retina sections for immunohistochemistry (IHC). Methods described include dissection of the ocular posterior cup, paraformaldehyde fixation, embedding in Optimal Cutting Temperature (OCT) media and tissue orientation, sectioning and immunostaining.

Preparação de Cryo-seções retinal do rato para immunohistochemistry

Preparation of high-quality mouse eye sections for immunohistochemistry (IHC) is critical for assessing the retinal structure and function and for ...

Optimization of the Retinal Vein Occlusion Mouse Model to Limit Variability

Mouse models of retinal vein occlusion (RVO) are often used in ophthalmology to study hypoxic-ischemic injury in the neural retina. In this report, a detailed method pointing out critical steps is provided with recommendations for optimization to achieve consistently successful occlusion rates across different genetically modified mouse strains. The RVO mouse model consists primarily of the intravenous administration of a photosensitizer dye followed by laser photocoagulation using a retinal imaging microscope attached to an ophthalmic guided laser. Three variables were identified as determinants of occlusion consistency. By adjusting the wait time after rose bengal administration and balancing the baseline and experimental laser output, the variability across experiments can be limited and a higher success rate of occlusions achieved. This method can be used to study retinal diseases that are characterized by retinal edema and hypoxic-ischemic injury. Additionally, as this model induces vascular injury, it can also be applied to study the neurovasculature, neuronal death, and inflammation.

Here, we describe an optimized protocol for retinal vein occlusion using rose bengal and a laser-guided retinal imaging microscope system with recommendations to maximize its reproducibility in genetically modified strains.

Otimização do Modelo de Oclusão de Veia da Retina em Camundongo para Limitar a Variabilidade

Mouse models of retinal vein occlusion (RVO) are often used in ophthalmology to study hypoxic-ischemic injury in the neural retina. In this report, a ...