Funding from the Australian Research Council (ARC) and National Health and Medical Research Council (NHMRC) is gratefully acknowledged.

The authors have nothing to disclose.

O modelo de rato canulação linfático mesentérico permite a quantificação directa da concentração e da taxa de transporte de várias células e moléculas (tais como lipidos e medicamentos) a partir do intestino para a linfa e as modificações dos mesmos que ocorrem em resposta ao desafio de várias substâncias (dieta , antigénios, fármacos, formulações, etc.) e 10,27 doença (cancro, vírus, colite, resistência à insulina, etc) 5-7. Os componentes recolhidas na lin...

A linfa flui a partir do intestino delgado através de um processo unidireccional que se origina no lacteals únicos que estão contidos dentro de cada pequena vilosidades intestinais 1. Lacteals são relativamente permeáveis ​​a fluidos, macromoléculas e as células e, assim, a formação de linfa começa com a entrada destes factores em lacteals. A linfa inicial nos lacteals flui posteriormente a partir do intestino através de uma rede de microvasos linfáticos, coletando (aferentes) vasos linfáticos, uma série de linfonodos mesentéricos e, finalmente, os vasos linfáticos pós-nodal (eferente). Dentro dos nodos, linfa passa através de uma série de cavidades medulares onde a troca ocorre com as células imunitárias residentes nó assim como o material que entram no nó do sangue. Todos linfa flui do intestino delgado, eventualmente, converge para o ducto eferente linfa mesentérica superior e, posteriormente, a cisterna do quilo. A cisterna do quilo também recolhe drenagem linfática os tecidos periféricos caudais, intestinal, regiões hepáticas e lombar e junta-se o duto linfático torácico, juntamente com a linfa do mediastino e partes do crânio do corpo. O ducto linfático torácico esvazia linfa diretamente no sistema venoso na junção das veias jugular interna e subclávia esquerda. O protocolo aqui descrito, o que permite a recolha de linfa directamente a partir da conduta de linfa mesentérica superior, facilitando, assim, a análise de vários factores que transitam directamente a partir do intestino para a circulação sistémica (geral) através do sistema linfático intestinal. As principais funções fisiológicas atribuídos ao sistema linfático intestinal são para manter o equilíbrio de fluidos, para facilitar a absorção de lípidos e molécula lipofílica, e para permitir que as respostas imunes adequadas 1. As células tumorais e vírus também se propagar através dos vasos linfáticos intestinais 2-4 e principais mudanças ocorrem dentro dos vasos linfáticos em várias patologias inflamatórias e metabólicas 5-7. Latanulation do ducto linfático mesentérico para recolher linfa dentro do mesentério permite uma análise de fluxo de fluido a granel através dos vasos linfáticos intestinais, bem como a quantificação da taxa de concentração e transporte de várias células e moléculas. Alterações na concentração ou o trânsito desses fatores na resposta a vários desafios (por exemplo: dietas, antígenos, drogas) e em modelos de doenças (por exemplo, colite, HIV, diabetes) podem também ser avaliadas. Embora seja impossível para descrever exaustivamente cada componente de linfa, que podem ser analisados ​​e comparados aqui, linfa mesentéricos simplista consiste aquosa, de lípidos e fases celulares. Os componentes de interesse na fase aquosa incluem péptidos e proteínas tais como antigénios ou tolerogénios 8, mensageiros imunes, tais como citocinas e mediadores de mastócitos, e mediadores 9 metabólicas tais como as incretinas 10. A fração celular da linfa mesentérica pós-nodal é composto quase inteiramente (mais de 99%) de lymphocytes 11. Várias células imunológicas (células dendríticas, mastócitos, etc.) penetram nos vasos linfáticos mesentéricos pré-nodais, mas permanecem dentro do nó 12. Se as células dentro da linfa aferente são de interesse, é possível recolher essas células por meio de remoção dos gânglios linfáticos mesentéricos de vários dias antes da canulação da conduta de linfa mesentéricos 12. Desta forma, as condutas linfáticos aferentes e eferentes são directamente ligados e as células linfáticas em linfa aferente passar directamente para o tubo linfático mesentérico. O trânsito e fenótipo de várias células do sistema imunológico que passam através dos vasos linfáticos intestinais podem, assim, ser examinado. Talvez a razão mais comum citada para a coleta de linfa mesentérica, até à data, no entanto, é estudar o processamento intestinal, absorção e transporte de lipídios na dieta e moléculas lipofílicas 10. Após a ingestão, os lípidos da dieta são digeridos (por exemplo, a partir de triglicéridos de ácidos gordos e de monoglicérido, phospholipid de ácidos gordos e de lisofosfolípido, e éster de colesterol de ácido gordo e de colesterol, etc.) e dispersos no lúmen intestinal em pequena das micelas e vesículas através da adição de compostos anfifílicos de bílis (fosfolípidos, colesterol e sais biliares) e a acção de enzimas pancreáticas 10,13. De lá eles são absorvidos enterócitos. A proporção dos componentes absorvidos são re-esterificados para formar triglicéridos, fosfolípidos e ésteres de colesterol no interior das células de absorção (enterócitos). Estes lípidos re-esterificados são montados a partir de uma combinação de componentes lipídicos exogenamente ingerida e componentes lipídicos endógenos da bílis segregada, piscinas ou lípidos da mucosa intestinal o fornecimento de sangue 13. A partir daqui os lípidos estéril içados são armazenados dentro de enterócitos ou montados em lipoproteínas intestinais (quilomicrons, lipoproteínas de muito baixa densidade (VLDL)) em conjunto com várias outras apoproteínas e moléculas lipofílicas ( <em&gt;, por exemplo, vitaminas) 10,13. Depois de sair enterócitos, lipoproteínas são especificamente transportados a partir do intestino para a circulação sistémica através do sistema linfático mesentérico como lacteals intestinais são mais permeáveis ​​a sua entrada do que os capilares sanguíneos intestinais. A proporção de componentes lipídicos são também absorvidos transportados a partir do intestino para o sistema circulatório através dos capilares sanguíneos e veia porta como, não só lipoproteína associados, 14 moléculas. Em geral, no entanto, a via de transporte da veia portal é apenas um actor importante na absorção de lípidos de comprimento de cadeia curto e médio prazo. A recolha de linfa mesentéricos permite assim a avaliação do transporte de lipoproteínas e os componentes associados (lípidos, moléculas lipofílicas, apo-proteínas) a partir do intestino. As lipoproteínas podem ser quantificados e caracterizado com a vantagem de que as lipoproteínas linfáticos mesentéricos, em geral, estão em uma nascenestado t, uma vez que não foram extensivamente modificado por enzimas sistêmicas tais como lipoproteína lipase 15. Embora o modelo de rato canulada linfático mesentérico foi talvez historicamente sido mais extensivamente descrito para a análise de transporte de lípido / lipoproteína a partir do intestino, uma área de expansão interesse é o papel de vasos linfáticos no transporte de fármacos lipofílicos, pró-drogas e outros xenobióticos 13,16 que é o foco do modelo descrito aqui. Fármacos lipofílicos (geralmente aqueles com log P&gt; 5 e solubilidade em cadeia longa triglicéridos&gt; 50 mg / g, embora exceções são aparentes) 17,18, pró-drogas 19 e outros xenobióticos 13,16 pode ter acesso aos vasos linfáticos intestinais passivamente ou por integrar activamente em lipoproteínas intestinal vias de transporte 19. O rato linfa mesentérica técnica de punção, portanto, tem muitas aplicações. Bollman et al. Descreveu pela primeira vez um technique para canular a conduta de linfa mesentéricos de ratos em 1948 20. Desde então um certo número de variantes do modelo foram descritos. Por exemplo, a coleta pode ocorrer quando o rato é anestesiados com vários anestésicos 21,22, ou no estado consciente enquanto conteve 15 ou mover livremente 23,24. Os ratos podem ser administrados diferentes soluções de reidratação e outras substâncias, tais como lípidos e de formulações de drogas em taxas diferentes no estômago, intestino ou parentérica (tipicamente 0-5 ml / h) 25. Em alguns estudos, o ducto torácico linfático em vez de ducto linfático mesentérico é canulada para estimar o transporte a partir do intestino através dos vasos linfáticos, embora isto possa subestimar o trânsito do intestino delgado, dependendo o factor de interesse, como a conduta de linfócito torácico recebe também a partir de linfa outra regiões 22,26. Modelos de canulação linfáticos também foram descritos em várias outras espécies, incluindo ratos 15,27, mini-pigs 12, 28,29 ovelhas, porcos e cães 30 31. No entanto, o modelo de rato é o mais amplamente e de forma consistente citados. Protocolos detalhados para canulação do ducto linfático mesentérica seguido da coleta de linfa no consciente 25 ou anestesiados 22 ratos e camundongos 15,27 foram publicados anteriormente e o leitor interessado é direcionado para estes protocolos. Este protocolo é o primeiro a demonstrar a técnica em um formato visualizado. O modelo de rato linfa cânula tem vantagens sobre animais de grande porte em termos de despesa, a facilidade da cirurgia e considerações éticas. Quando comparado com o modelo do rato, mesentérica linfa cirurgia cannulation também é mais fácil no rato, embora o modelo de rato permite estudos mais detalhados em animais transgênicos 27. No entanto, existem algumas limitações do modelo de rato, particularmente aqueles associados com diferenças na fisiologia, esse limite extrapolatião positivo para outras situações pré-clínicos e clínicos. Por exemplo, o fluxo de bílis no rato é constante e independente da ingestão de alimentos enquanto que na maior comida lipídios espécies ou estimular o fluxo de bílis 32. Isso cria desafios para a obtenção de ambientes de pré e pós-prandial representativos no rato que refletem o que é visto em espécies e seres humanos maiores. Para os estudos de distribuição de drogas, espécies maiores também podem ser preferidos na avaliação dos transportes linfática após a administração da dose humana realista forma 25. Em um estudo recente, as taxas de transporte de lipídios na linfa mesentérica foram encontrados para ser comparáveis ​​entre espécies (rato, cão) após a administração de uma massa equivalente e tipo de lipídio que fornece alguma confiança na extrapolação de dados de transporte de lipídios entre espécies 27. No entanto, o transporte de um modelo lipofílico de drogas, halofantrina, classificados em ordem de tamanho do animal (ou seja, cão&gt; rat&gt; mouse). Um fator de escala pode, assim, ser obrigado a extrapolate dados de transporte de drogas linfáticos de rato a outras espécies. Uma limitação dos modelos de canulação de linfa, em geral, é que a recolha de linfa passiva directamente a partir de uma conduta linfático pode modificar o fluxo linfático e de transporte uma vez que os vasos linfáticos trabalhar contra um gradiente de pressão que é alterada uma vez que o recipiente 33 é canulada. O modelo cannulation linfático também pode ser difícil de estabelecer, em laboratórios que não estão familiarizados com a técnica. Modelos alternativos têm sido assim descrito. Por exemplo, o transporte de factores através do sistema linfático intestinal, tais como lipoproteínas e moléculas lipofílicas, foi estudado indirectamente através de recolha do sangue. Um desses modelos envolve a comparação de concentrações de lípidos no sangue e / ou drogas, após a administração oral, na presença e na ausência de inibidores (por exemplo, colchicina, Pluronic L81, ciclo-heximida) produção de lipoproteína intestinal que bloqueie o transporte linfático 34. Uma vantagemde modelos que quantificam transporte linfático indiretamente por meio da coleta de amostras de sangue é que ele permite alguma avaliação do transporte linfático em humanos como cirurgia invasiva não é necessária 35. No entanto, os inibidores de transporte linfático não são específicas e factores que são transportados através dos vasos linfáticos são diluídos e modificado na circulação sistémica que complica estas avaliações. In vitro alternativas também têm sido descritos. Por exemplo, Caco-2 celulares ou isolado enterócitos culturas têm sido utilizados para estudar mais detalhadamente a secreção intestinal de moléculas que entram nos vasos linfáticos 36-38. Um modelo avançado in vitro que é mais representativo do microambiente intestinal humana também foi descrita recentemente 39. Neste modelo, uma camada de células endoteliais linfáticas é co-cultivadas com células Caco-2, que permite uma análise mais detalhada da transferência de substâncias a partir do intestino para o sistema linfático. No entanto, em vitro sistemas de células não possuem fluxo cambial e transferir ou seja, a interligação com um lúmen intestinal e sangue subjacente e suprimento vascular linfático. Em uma abordagem alternativa, Kassis et al. Estabeleceram um dual-channel (alta velocidade vídeo de campo brilhante e fluorescência), em sistema de imagem situ que permite comparações quantitativas entre contração dos vasos, o fluxo de linfa e concentrações de lipídios fluorescentes em vasos linfáticos mesentéricos 33. Uma vantagem deste modelo sobre o acima mencionado em sistemas in vitro é que ele permite a localização precisa da passagem de células do sistema imunológico através dos vasos linfáticos. Medições absolutas de massa de lípidos (ou medicamento) de transporte são, no entanto, ainda não está estabelecida utilizando métodos de imagem. Estudos in vitro e in silico abordagens especificamente para prever o grau de transporte da droga lipófila através dos vasos linfáticos intestinais foram também publicados 40-42. Por exemplo, a afinidade ex vivo de vários compounds para chylomicrons plasma correlacionou-se razoavelmente bem com o seu transporte linfático in vivo 41. Posteriormente, o mesmo grupo estabeleceu um modelo em silico para prever a afinidade da droga para chylomicrons com base em múltiplos de 40 propriedades físico-químicas. Holm et al., Também estabelecida uma relativamente complexo no modelo para prever silico imediato transporte linfático de compostos lipofílicos em função dos descritores moleculares 42. Estes modelos podem proporcionar uma abordagem útil para prever a extensão de transporte linfático de drogas desconhecidas. A validação dos modelos com uma grande variedade de drogas e em diferentes laboratórios, no entanto, ser necessário para confirmar a sua precisão e reprodutibilidade. A canulação do canal linfático mesentérico permanece, assim, os únicos meios para examinar directamente o conteúdo de drenagem linfática do intestino delgado e a velocidade de trânsito do complexo conjunto de factores (células, proteínas,peptídeos, lipídios, medicamentos) a linfa em uma situação in vivo. Aqui nós descrevemos um protocolo para a canulação do ducto linfático e carótida artéria mesentérica, que permite a coleta de linfa mesentérica e arterial sistêmica de ratos anestesiados. Os dados representativos demonstram como o modelo pode ser usado para examinar o transporte de lípidos e de drogas a partir do intestino, através do sistema linfático mesentérico. Isto é seguido por uma discussão das dificuldades que podem ser encontradas no estabelecimento do modelo e um guia de resolução de problemas. Uma vez estabelecido o modelo é uma ferramenta poderosa para investigar transporte linfático intestinal.

<table border="0" cellpadding="0" cellspacing="0" >
	<tbody>
		<tr >
			<td >Sterile saline</td>
			<td>Baxter healthcare</td>
			<td>AHB 1307</td>
			<td>Any brand can be used. Example here is Baxter 100 ml saline bags, box of 50</td>
		</tr>
		<tr >
			<td >70 % ethanol in water</td>
			<td>Any</td>
			<td></td>
			<td>Any brand can be used</td>
		</tr>
		<tr >
			<td >Chlorhexidine gluconate solution (Microshield 4)</td>
			<td>Livingstone International</td>
			<td>JJ60243L</td>
			<td>Any brand can be used. http://www.livingstone.com.au/?PG=search_result&#38;CAT=6&#38;search 
			=JJ60243L</td>
		</tr>
		<tr >
			<td >Betadine solution</td>
			<td>Livingstone International</td>
			<td>BU0510</td>
			<td>Any brand can be used. http://www.livingstone.com.au/?PG=search_result&#38;CAT=6&#38;search 
			=BU0510</td>
		</tr>
		<tr >
			<td >Ilium Ketamil (Ketamine 100 mg/ml)</td>
			<td >PROVET VICTORIA&#160;</td>
			<td >KETA I 1</td>
			<td>http://www.provet.com.au/</td>
		</tr>
		<tr >
			<td >Ilium Xylazil (Xylazine 100 mg/ml)</td>
			<td >PROVET VICTORIA&#160;</td>
			<td >TRO-3828</td>
			<td>http://www.provet.com.au/</td>
		</tr>
		<tr >
			<td >ACP 10 Injection (Acepromazine 10 mg/ml)</td>
			<td >PROVET VICTORIA&#160;</td>
			<td >VTG-DACP010020</td>
			<td>http://www.provet.com.au/</td>
		</tr>
		<tr >
			<td >Sodium pentobarbitone</td>
			<td>PROVET VICTORIA&#160;</td>
			<td>24529</td>
			<td>Any brand can be used. Example here is Lethabarb&#174; 325 mg/ml sodium pentobarbitone, Virbac Animal Health. http://www.provet.com.au</td>
		</tr>
		<tr >
			<td >Heparin (35000I.U. in 35 mL)</td>
			<td>Sigma Pharmaceuticals</td>
			<td>337220</td>
			<td>http://sigmaco.com.au/</td>
		</tr>
		<tr >
			<td >Ethylenediaminetetraacetic acid (EDTA) disodium salt dihydrate</td>
			<td >Sigma-Aldrich</td>
			<td >E1644</td>
			<td>Any brand can be used. Example here is disodium salt of EDTA from Sigma.&#160;</td>
		</tr>
		<tr >
			<td >Polyethylene (PE) cannula o.d. 0.96 mm x i.d. 0.58 mm</td>
			<td>Microtube extensions</td>
			<td>PE8050</td>
			<td>Any brand can be used. Example here is PE tubing 0.8x0.5 mm, 30 m</td>
		</tr>
		<tr >
			<td >Polyethylene (PE) cannula o.d. 0.8 mm x i.d. 0.5 mm</td>
			<td>Microtube extensions</td>
			<td>PE9658</td>
			<td>Any brand can be used. Example here is PE tubing 0.96x0.58 mm, 30 m</td>
		</tr>
		<tr >
			<td >Ruler</td>
			<td>Any</td>
			<td ></td>
			<td>Any brand can be used</td>
		</tr>
		<tr >
			<td >Markers</td>
			<td>Any</td>
			<td ></td>
			<td>Any brand can be used</td>
		</tr>
		<tr >
			<td >Cigarette lighter</td>
			<td>Any</td>
			<td ></td>
			<td>Any brand can be used</td>
		</tr>
		<tr >
			<td >Cyanoacrylate glue</td>
			<td>Any</td>
			<td ></td>
			<td>Any brand can be used</td>
		</tr>
		<tr >
			<td >23 gauge needles</td>
			<td>Livingstone International</td>
			<td>DN23GX0.75LV</td>
			<td>Any brand can be used. Example here is Livingstone Disposable Needle, Sterile, 23GX0.75inch, 100/BOX. http://www.livingstone.com.au/?PG=search_result&#38;CAT= 
			6&#38;search=DN23GX0.75LV</td>
		</tr>
		<tr >
			<td >25 gauge needles</td>
			<td>Livingstone International</td>
			<td>DN25GX1.0LV</td>
			<td>Any brand can be used. Example here is Livingstone Disposable Needle, Sterile, 25GX1.0inch, 100/BOX. http://www.livingstone.com.au/?PG=search_result&#38;CAT=6&#38;search= 
			DN25GX1.0LV</td>
		</tr>
		<tr >
			<td >1 ml syringe</td>
			<td>Livingstone International</td>
			<td>T3SS01TA</td>
			<td>Any brand can be used. Example here is Terumo syringe 1 ml Slip Tuberculin 100/Box. http://www.livingstone.com.au/?PG=search_result&#38;CAT=6&#38;search 
			=T3SS01TA</td>
		</tr>
		<tr >
			<td >10 ml syringe</td>
			<td>Livingstone International</td>
			<td>T3SS10SA</td>
			<td>Any brand can be used. Example here is Terumo syringe 10 ml Slip 100/Box. http://www.livingstone.com.au/?PG=search_result&#38;CAT=6&#38;search 
			=T3SS10SA</td>
		</tr>
		<tr >
			<td >Gauze swabs</td>
			<td>Livingstone International</td>
			<td>GSC075</td>
			<td>Any brand can be used and cut to required size. Example here is gauze swabs cotton filled 7.5x7.5 cm, 8 ply. http://www.livingstone.com.au/?PG=search_result&#38;CAT=6&#38;search 
			=GSC075</td>
		</tr>
		<tr >
			<td >Cotton buds</td>
			<td>Livingstone International</td>
			<td>CTAST075DP</td>
			<td>Any brand can be used. Example here is Livingstone cotton applicator plastic double tipped. 75MM. 100/PK. http://www.livingstone.com.au/?PG=search_result&#38;CAT=6&#38;search 
			=CTAST075DP</td>
		</tr>
		<tr >
			<td >Heating pad</td>
			<td>Ratek</td>
			<td>WT1</td>
			<td>Any brand that keeps temperature at 37C can be used. Example here is Ratek warming tray.</td>
		</tr>
		<tr >
			<td >Surgical light</td>
			<td>Harvard Apparatus</td>
			<td>72-0215 with 72-0267</td>
			<td>Any brand can be used. Example here is Harvard apparatus V-Lux 1000 Cold Light Source with Bifurcated Gooseneck Light Guide, Black, 4.7 mm fiber diameter (each arm). http://www.harvardapparatus.com/webapp/wcs/stores/servlet/product_11051_10001_50601_ 
			-1_HAI_ProductDetail and&#160; http://www.harvardapparatus.com/webapp/wcs/stores/servlet/product_11051_10001_35487_ 
			-1_HAI_ProductDetail___</td>
		</tr>
		<tr >
			<td >Surgical microscope</td>
			<td>Zeiss</td>
			<td>495005-0014-000</td>
			<td>Any brand can be used. Example here is Zeiss Stereomicroscope Stemi 2000-C with Stand S Double Spot and KL 300 LED. https://www.micro-shop.zeiss.com/?l=en&#38;p=us&#38;f=e&#38;i=10143</td>
		</tr>
		<tr >
			<td >Silk suture</td>
			<td>Livingstone International</td>
			<td>DTSK163019F4</td>
			<td>Any brand can be used. Example here is *&#160; 
			Email this item to my friend 
			3/8 Circle Reverse Cut Silk Suture 3/0 Thread 19mm. http://www.livingstone.com.au/?PG=search_result&#38;CAT=6&#38;search 
			=DTSK163019F4</td>
		</tr>
		<tr >
			<td >Scalpel blades</td>
			<td >Fine Science Tools (FST)</td>
			<td >10020-00</td>
			<td>Any brand can be used. Example here is FST Scalpel Blade #20. http://www.finescience.ca/Special-Pages/Products.aspx?ProductId=191</td>
		</tr>
		<tr >
			<td >Scalpel handle</td>
			<td >Fine Science Tools (FST)</td>
			<td>10004-13</td>
			<td>Any brand can be used. Example here is FST Scalpel Handle #4. http://www.finescience.ca/Special-Pages/Products.aspx?ProductId=298&#38;CategoryId=51</td>
		</tr>
		<tr >
			<td >1 x Small surgical scissors</td>
			<td >Fine Science Tools (FST)</td>
			<td>14060-09</td>
			<td>Any brand can be used. Example here is FST Fine Scissors, 9 cm with 21 mm cutting edge, sharp, straight. http://www.finescience.ca/Special-Pages/Products.aspx?ProductId=40&#38;CategoryId=17</td>
		</tr>
		<tr >
			<td >2 x Forceps with serrated curved tip</td>
			<td >Fine Science Tools (FST)</td>
			<td >11001-13</td>
			<td>Any brand can be used. Example here is FST 13 cm standard pattern forceps with curved 2.8x1.4 mm tip. http://www.finescience.ca/Special-Pages/Products.aspx?ProductId=405&#38;CategoryId=32</td>
		</tr>
		<tr >
			<td >1 x Iridectomy scissors</td>
			<td >Fine Science Tools (FST)</td>
			<td>15000-08</td>
			<td>Any brand can be used. Example here is FST Vannas Spring Scissors - 2.5mm Cutting Edge, Straight. http://www.finescience.ca/Special-Pages/Products.aspx?ProductId=17&#38;CategoryId=16&#160;</td>
		</tr>
		<tr >
			<td >1 x Forceps with straight serated tip</td>
			<td >Fine Science Tools (FST)</td>
			<td>11650-10</td>
			<td>Any brand can be used. Example here is FST Graefe 10 cm straight with serrated 1 x 0.99 mm tip. http://www.finescience.ca/Special-Pages/Products.aspx?ProductId=390&#38;CategoryId=32</td>
		</tr>
		<tr >
			<td >1 x Forceps with smooth sharp straight fine tip</td>
			<td >Fine Science Tools (FST)</td>
			<td>11251-10</td>
			<td>Any brand can be used. Example here is FST Dumont #5 forceps straight 11cm with 0.08 x 0.04mm tip. http://www.finescience.ca/Special-Pages/Products.aspx?ProductId=335&#38;CategoryId=29</td>
		</tr>
		<tr >
			<td >1 x Forceps with smooth fine curved forceps</td>
			<td >Fine Science Tools (FST)</td>
			<td>11063-07</td>
			<td>Any brand can be used. Example here is FST Delicate Forceps 9 cm with smooth 0.4 x 0.3mm tip. http://www.finescience.ca/Special-Pages/Products.aspx?ProductId=360</td>
		</tr>
		<tr >
			<td >2 x Hemostats</td>
			<td >Fine Science Tools (FST)</td>
			<td >13010-12</td>
			<td>Any brand can be used. Not all operators use the hemostats. Example here is FST 12 cm Micro-Mosquito Hemostats with 20 mm length x 1.3 mm width serrated, straight tip. http://www.finescience.ca/Special-Pages/Products.aspx?ProductId=377&#38;CategoryId=33</td>
		</tr>
		<tr >
			<td >1 x Suture needle holder</td>
			<td >Fine Science Tools (FST)</td>
			<td>12001-13</td>
			<td>Any brand can be used. Example here is FST 13cm Hasley Needle Holder with 16 mm length x 1.9 mm width tip. http://www.finescience.ca/Special-Pages/Products.aspx?ProductId=254&#38;CategoryId=70</td>
		</tr>
		<tr >
			<td >1 x Artery clamp</td>
			<td >Fine Science Tools (FST)</td>
			<td>18050-28</td>
			<td>Any brand can be used. Example here is FST Bulldog Serrefines straight, 28 mm long, 9x1.6 mm jaw dimension with medium clamp press. http://www.finescience.ca/Special-Pages/Products.aspx?ProductId=270&#38;CategoryId=82</td>
		</tr>
		<tr >
			<td >Oleic acid</td>
			<td >Sigma Aldrich</td>
			<td >O1008</td>
			<td>When required, any brand can be used. Example here is 99% pure oleic acid. http://www.sigmaaldrich.com/catalog/product/sial/o1008?lang=en&#38;region=AU</td>
		</tr>
		<tr >
			<td >14C-oleic acid</td>
			<td >Perkin&#160;</td>
			<td>NEC317050UC&#160;</td>
			<td>Any brand can be used. Example here is Oleic Acid, [1-14C]-, 50&#181;Ci (1.85MBq). http://www.perkinelmer.com/Catalog/Product/ID/NEC317050UC</td>
		</tr>
		<tr >
			<td >Sodium taurocholate</td>
			<td >Sigma Aldrich</td>
			<td >T4009</td>
			<td>Any brand can be used. Example here is taurocholic acid sodium salt hydrate &#8805;95% (TLC) . http://www.sigmaaldrich.com/catalog/product/sigma/t4009?lang=en&#38;region=AU</td>
		</tr>
		<tr >
			<td >Halofantrine</td>
			<td >Glaxo Smith Kline</td>
			<td ></td>
			<td>Halofantrine was kindly provided as a gift from Glaxo Smith Kline</td>
		</tr>
		<tr >
			<td >Sodium phosphate monobasic</td>
			<td >Sigma Aldrich</td>
			<td >71507</td>
			<td >Any brand can be used. Example here is sodium phosphate monobasic monohydrate, BioXtra, for molecular biology, &#62;99.5%. http://www.sigmaaldrich.com/catalog/product/sigma/71643?lang=en&#38;region=AU</td>
		</tr>
		<tr >
			<td >Sodium phosphate dibasic</td>
			<td >Sigma Aldrich</td>
			<td >71643</td>
			<td >Any brand can be used. Example here is sodium phosphate dibasic dihydrate, BioUltra, for molecular biology, &#62;99%. http://www.sigmaaldrich.com/catalog/product/sigma/71507?lang=en&#38;region=AU</td>
		</tr>
	</tbody>
</table>

the mesenteric lymph duct cannulated rat model: application to the assessment of intestinal lymphatic drug transport

O sistema linfático intestinal desempenha um papel-chave no transporte de fluidos, a absorção de lipídios e função imunológica. A linfa flui directamente a partir do intestino delgado através de uma série de vasos linfáticos e dos nodos que convergem na conduta de linfa mesentérica superior. A canulação do canal linfático mesentérico permite assim a obtenção de linfa mesentéricos que flui a partir do intestino. Linfático mesentérico consiste de uma fracção celular de células imunitárias (99% de linfócitos), fracção aquosa (fluido, péptidos e proteínas, tais como as citoquinas e as hormonas do intestino) e fracção de lipoproteína (lípidos, moléculas lipofílicas e apo-proteínas). O modelo de canulação ducto linfático mesentérico pode, portanto, ser usadas para medir a concentração e velocidade de transporte de uma variedade de factores a partir do intestino, através do sistema linfático. Alterações a estes factores em resposta a desafios diferentes (por exemplo, dietas, antigénios, medicamentos) e na doença (por exemplo, doença inflamatória do intestino, HIV, diabetes) pode também be determinada. Uma área de interesse é expandir o papel do transporte linfático na absorção de drogas e pró-drogas lipofílicas administrados por via oral que se associam com as vias de absorção intestinal de lipídios. Descrevemos aqui, em detalhe, um modelo de rato canulado ducto linfático mesentérico, que permite a avaliação da taxa e extensão de lípido e o transporte da droga através do sistema linfático, durante várias horas, após a libertação intestinal. O método é facilmente adaptável para a medição de outros parâmetros de linfa. Nós fornecer descrições detalhadas das dificuldades que podem ser encontradas ao estabelecer esse método cirúrgico complexo, bem como dados representativos de experiências fracassadas e bem sucedidas para fornecer instruções sobre como confirmar o sucesso experimental e interpretar os dados obtidos.

Os resultados de uma experiência representativa para quantificar a extensão cumulativa e taxa de lípido e o transporte da droga através do sistema linfático intestinal após o parto utilizando o modelo de canulação da linfa mesentéricos são mostrados na Figura 4 e na Figura 5. Nesta experiência, 200 ug do modelo lipofílico halofantrina fármaco foi administrado dentro do duodeno de ratos ao longo de 2 horas, em uma formulação contendo 40 mg de ácido oleico (incluindo 2-5 u...

Watch this Scientific Journal Video about The Mesenteric Lymph Duct Cannulated Rat Model: Application to the Assessment of Intestinal Lymphatic Drug Transport at JoVE.com

The Mesenteric Lymph Duct Cannulated Rat Model: Application to the Assessment of Intestinal Lymphatic Drug Transport

Here we describe a technique to cannulate the mesenteric lymph duct in rats which enables quantification of lipid and drug transport via the lymphatic system following intestinal delivery. The technique can be adapted to assess mesenteric lymph concentrations and/or transport of fluid, immune cells, peptides, proteins and lipophilic molecules.

A linfa mesentérica Duct canulada Rat Modelo: Aplicação para a Avaliação de Intestinal Linfática transporte da droga

The intestinal lymphatic system plays key roles in fluid transport, lipid absorption and immune function. Lymph flows directly from the small intestine ...

the-mesenteric-lymph-duct-cannulated-rat-model-application-to

Research

JoVE Journal

Immunology and Infection

28.2K visualizações.  Monash University (Parkville Campus). Here we describe a technique to cannulate the mesenteric lymph duct in rats which enables quantification of lipid and drug transport via the lymphatic system following intestinal delivery. The technique can be adapted to assess mesenteric lymph concentrations and/or transport of fluid, immune cells, peptides, proteins and lipophilic molecules.

Vídeo: The Mesenteric Lymph Duct Cannulated Rat Model: Application to the Assessment of Intestinal Lymphatic Drug Transport

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 do linfonodo inguinal

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 ...

Imunologia e Infecção

Intravital Imaging of the Mouse Popliteal Lymph Node

Lymph nodes (LNs) are secondary lymphoid organs, which are strategically located throughout the body to allow for trapping and presentation of foreign antigens from peripheral tissues to prime the adaptive immune response. Juxtaposed between innate and adaptive immune responses, the LN is an ideal site to study immune cell interactions1,2. Lymphocytes (T cells, B cells and NK cells), dendritic cells (DCs), and macrophages comprise the bulk of bone marrow-derived cellular elements of the LN. These cells are strategically positioned in the LN to allow efficient surveillance of self antigens and potential foreign antigens3-5. The process by which lymphocytes successfully encounter cognate antigens is a subject of intense investigation in recent years, and involves an integration of molecular contacts including antigen receptors, adhesion molecules, chemokines, and stromal structures such as the fibro-reticular network2,6-12. 
Prior to the development of high-resolution real-time fluorescent in vivo imaging, investigators relied on static imaging, which only offers answers regarding morphology, position, and architecture. While these questions are fundamental in our understanding of immune cell behavior, the limitations intrinsic with this technique does not permit analysis to decipher lymphocyte trafficking and environmental clues that affect dynamic cell behavior. Recently, the development of intravital two-photon laser scanning microscopy (2P-LSM) has allowed investigators to view the dynamic movements and interactions of individual cells within live LNs in situ12-16. In particular, we and others have applied this technique to image cellular behavior and interactions within the popliteal LN, where its compact, dense nature offers the advantage of multiplex data acquisition over a large tissue area with diverse tissue sub-structures11,17-18. It is important to note that this technique offers added benefits over explanted tissue imaging techniques, which require disruption of blood, lymph flow, and ultimately the cellular dynamics of the system. Additionally, explanted tissues have a very limited window of time in which the tissue remains viable for imaging after explant. With proper hydration and monitoring of the animal's environmental conditions, the imaging time can be significantly extended with this intravital technique. Here, we present a detailed method of preparing mouse popliteal LN for the purpose of performing intravital imaging.

Recent advances in 2-photon microscopy have enabled real-time in situ imaging of live tissues in animal models, thereby enhancing our ability to investigate cellular behavior in both physiologic and pathologic conditions. Here, we outline the preparations required to perform intravital imaging of the mouse popliteal lymph node.

Imagem intravital do Linfonodo Popliteal Rato

Lymph nodes (LNs) are secondary lymphoid organs, which are strategically located throughout the body to allow for trapping and presentation of foreign ...

Non-invasive Optical Imaging of the Lymphatic Vasculature of a Mouse

The lymphatic vascular system is an important component of the circulatory system that maintains fluid homeostasis, provides immune surveillance, and mediates fat absorption in the gut. Yet despite its critical function, there is comparatively little understanding of how the lymphatic system adapts to serve these functions in health and disease1. Recently, we have demonstrated the ability to dynamically image lymphatic architecture and lymph "pumping" action in normal human subjects as well as in persons suffering lymphatic dysfunction using trace administration of a near-infrared fluorescent (NIRF) dye and a custom, Gen III-intensified imaging system2-4. NIRF imaging showed dramatic changes in lymphatic architecture and function with human disease. It remains unclear how these changes occur and new animal models are being developed to elucidate their genetic and molecular basis. In this protocol, we present NIRF lymphatic, small animal imaging5,6 using indocyanine green (ICG), a dye that has been used for 50 years in humans7, and a NIRF dye-labeled cyclic albumin binding domain (cABD-IRDye800) peptide that preferentially binds mouse and human albumin8. Approximately 5.5 times brighter than ICG, cABD-IRDye800 has a similar lymphatic clearance profile and can be injected in smaller doses than ICG to achieve sufficient NIRF signals for imaging8. Because both cABD-IRDye800 and ICG bind to albumin in the interstitial space8, they both may depict active protein transport into and within the lymphatics. Intradermal (ID) injections (5-50 &mu;l) of ICG (645 &mu;M) or cABD-IRDye800 (200 &mu;M) in saline are administered to the dorsal aspect of each hind paw and/or the left and right side of the base of the tail of an isoflurane-anesthetized mouse. The resulting dye concentration in the animal is 83-1,250 &mu;g/kg for ICG or 113-1,700 &mu;g/kg for cABD-IRDye800. Immediately following injections, functional lymphatic imaging is conducted for up to 1 hr using a customized, small animal NIRF imaging system. Whole animal spatial resolution can depict fluorescent lymphatic vessels of 100 microns or less, and images of structures up to 3 cm in depth can be acquired9. Images are acquired using V++ software and analyzed using ImageJ or MATLAB software. During analysis, consecutive regions of interest (ROIs) encompassing the entire vessel diameter are drawn along a given lymph vessel. The dimensions for each ROI are kept constant for a given vessel and NIRF intensity is measured for each ROI to quantitatively assess "packets" of lymph moving through vessels.

Recently developed imaging techniques using near-infrared fluorescence (NIRF) may help elucidate the role the lymphatic system plays in cancer metastasis, immune response, wound repair, and other lymphatic-associated diseases.

Não-invasiva de Imagem Óptico da vasculatura linfática de um rato

The lymphatic  vascular system is an important component of the circulatory system that  maintains fluid homeostasis, provides immune surveillance, and ...

Generation of Lymph Node-fat Pad Chimeras for the Study of Lymph Node Stromal Cell Origin

The stroma is a key component of the lymph node structure and function. However, little is known about its origin, exact cellular composition and the mechanisms governing its formation. Lymph nodes are always encapsulated in adipose tissue and we recently demonstrated the importance of this relation for the formation of lymph node stroma. Adipocyte precursor cells migrate into the lymph node during its development and upon engagement of the Lymphotoxin-b receptor switch off adipogenesis and differentiate into lymphoid stromal cells (B&#233;n&#233;zech&#160;et al.14). Based on the lymphoid stroma potential of adipose tissue, we present a method using a lymph node/fat pad chimera that allows the lineage tracing of lymph node stromal cell precursors. We show how to isolate newborn lymph nodes and EYFP+ embryonic adipose tissue and make a LN/ EYFP+ fat pad chimera. After transfer under the kidney capsule of a host mouse, the lymph node incorporates local adipose tissue precursor cells and finishes its formation. Progeny analysis of EYFP+ fat pad cells in the resulting lymph nodes can be performed by flow-cytometric analysis of enzymatically digested lymph nodes or by immunofluorescence analysis of lymph nodes cryosections. By using fat pads from different knockout mouse models, this method will provide an efficient way of analyzing the origin of the different lymph node stromal cell populations.

Generation of lymph node/fat pad chimeras for the study of lymph node stromal cell origin is described. The method involves the isolation of lymph nodes from newborn mice and embryonic fat pads, the generation of chimeric lymph node-fat pads, and their transfer under the kidney capsule of a host mouse.

The stroma is a key component of the lymph node structure and function. However, little is known about its origin, exact cellular composition and the ...

Magnetic Stirrer Method for the Detection of Trichinella Larvae in Muscle Samples

Trichinellosis is a debilitating disease in humans and is caused by the consumption of raw or undercooked meat of animals infected with the nematode larvae of the genus Trichinella. The most important sources of human infections worldwide are game meat and pork or pork products. In many countries, the prevention of human trichinellosis is based on the identification of infected animals by means of the artificial digestion of muscle samples from susceptible animal carcasses.
There are several methods based on the digestion of meat but the magnetic stirrer method is considered the gold standard. This method allows the detection of Trichinella larvae by microscopy after the enzymatic digestion of muscle samples and subsequent filtration and sedimentation steps. Although this method does not require special and expensive equipment, internal controls cannot be used. Therefore, stringent quality management should be applied throughout the test. The aim of the present work is to provide detailed handling instructions and critical control points of the method to analysts, based on the experience of the European Union Reference Laboratory for Parasites and the National Reference Laboratory of Germany for Trichinella.

Magnetic Stirrer Method for the Detection of Trichinella Larvae in Muscle Samples

The prevention of human trichinellosis in many countries worldwide is based on the laboratory examination of muscle samples from susceptible animals by methods of digestion, of which the magnetic stirrer method is considered the gold standard.

Método agitador magnético para Detecção de<em&gt; Trichinella</em&gt; As larvas em amostras de músculo

Trichinellosis is a debilitating disease in humans and is caused by the consumption of raw or undercooked meat of animals infected with the nematode ...

Quantitative Polymerase Chain Reaction-based Analyses of Murine Intestinal Microbiota After Oral Antibiotic Treatment

The gut microbiota has a central influence on human health. Microbial dysbiosis is associated with many common immunopathologies such as inflammatory bowel disease, asthma and arthritis. Thus, understanding the mechanisms underlying microbiota-immune system crosstalk is of crucial importance. Antibiotic administration, while aiding pathogen clearance, also induces drastic changes in the size and composition of intestinal bacterial communities which can have an impact on human health. Antibiotic treatment in mice recapitulates the impact and long-term changes in human microbiota from antibiotic treated patients, and enables investigation of the mechanistic links between changes in microbial communities and immune cell function. While several methods for antibiotic treatment of mice have been described, some of them induce severe dehydration and weight-loss complicating the interpretation of the data. Here, we provide two protocols for oral antibiotic administration which can be used for long-term treatment of mice without inducing major weight-loss. These protocols make use of a combination of antibiotics that target both Gram-positive and Gram-negative bacteria and can be provided either ad libitum in the drinking water or by oral gavage. Moreover, we describe a method for the quantification of microbial density in fecal samples by qPCR which can be used to validate the efficacy of the antibiotic treatment. The combination of these approaches provides a reliable methodology for the manipulation of the intestinal microbiota and the study of the effects of antibiotic treatment in mice.

Here we provide detailed protocols for the oral administration of antibiotics to mice, collection of fecal samples, DNA extraction and quantification of fecal bacteria by qPCR.

Polimerase quantitativos baseados na reação em cadeia análises de murino Microbiota Intestinal após o tratamento antibiótico Oral

The gut microbiota has a central influence on human health. Microbial dysbiosis is associated with many common immunopathologies such as inflammatory ...

Chronic Salmonella Infection Induced Intestinal Fibrosis

Tissue fibrosis characterized by the pathological accumulation of extracellular matrix such as collagen is the outcome of persistent inflammation and dysregulated repair. In inflammatory bowel disease (IBD), fibrosis leads to recurrent stricture formations for which there is no effective therapy other than surgical resection. Due to its late onset, the processes that drive fibrosis is less studied and largely unknown. Therefore, fibrotic complications represent a major challenge in IBD. In this protocol, a robust in vivo model of intestinal fibrosis is described where streptomycin pre-treatment of C57Bl/6 mice followed by oral gavage with vaccine grade Salmonella Typhimurium &#916;AroA mutant leads to persistent pathogen colonization and fibrosis of the cecum. Methodologies for preparing S. Typhimurium &#916;AroA for inoculation, quantifying pathogen loads in the cecum and spleen, and evaluating collagen deposition in intestinal tissues are explained. This experimental disease model is useful for examining host factors that either enhance or exacerbate CD-like intestinal fibrosis.

This protocol describes a mouse model of Salmonella driven intestinal fibrosis that resembles key pathological hallmarks of Crohn&#8217;s disease including transmural inflammation and fibrosis. This method can be used to evaluate host factors that alter fibrotic outcomes using mutant mice maintained on a C57Bl/6 genetic background.

Infecção crônica por Salmonella induzida por fibrose intestinal

Tissue fibrosis characterized by the pathological accumulation of extracellular matrix such as collagen is the outcome of persistent inflammation and ...

Blocking Lymph Flow by Suturing Afferent Lymphatic Vessels in Mice

Lymphatic vessels are critical in maintaining tissue fluid balance and optimizing immune protection by transporting antigens, cytokines, and cells to draining lymph nodes (LNs). Interruption of lymph flow is an important method when studying the function of lymphatic vessels. The afferent lymphatic vessels from the murine footpad to the popliteal lymph nodes (pLNs) are well-defined as the only routes for lymph drainage into the pLNs. Suturing these afferent lymphatic vessels can selectively prevent lymph flow to the pLNs. This method allows for interference in lymph flow with minimal damage to the lymphatic endothelial cells in the draining pLN, the afferent lymphatic vessels, as well as other lymphatic vessels around the area. This method has been used to study how lymph impacts high endothelial venules (HEV) and chemokine expression in the LN, and how lymph flows through the adipose tissue surrounding the LN in the absence of functional lymphatic vessels. With the growing recognition of the importance of lymphatic function, this method will have broader applications to further unravel the function of lymphatic vessels in regulating the LN microenvironment and immune responses.

A protocol to block lymph flow by surgical suturing of afferent lymphatic vessels is presented.

Bloqueando o fluxo linfático suturing afferent vasos linfáticos em camundongos

Lymphatic vessels are critical in maintaining tissue fluid balance and optimizing immune protection by transporting antigens, cytokines, and cells to ...

Functional Assessment of Intestinal Permeability and Neutrophil Transepithelial Migration in Mice using a Standardized Intestinal Loop Model

The intestinal mucosa is lined by a single layer of epithelial cells that forms a dynamic barrier allowing paracellular transport of nutrients and water while preventing passage of luminal bacteria and exogenous substances. A breach of this layer results in increased permeability to luminal contents and recruitment of immune cells, both of which are hallmarks of pathologic states in the gut including inflammatory bowel disease (IBD). 
Mechanisms regulating epithelial barrier function and transepithelial migration (TEpM) of polymorphonuclear neutrophils (PMN) are incompletely understood due to the lack of experimental in vivo methods allowing quantitative analyses. Here, we describe a robust murine experimental model that employs an exteriorized intestinal segment of either ileum or proximal colon. The exteriorized intestinal loop (iLoop) is fully vascularized and offers physiological advantages over ex vivo chamber-based approaches commonly used to study permeability and PMN migration across epithelial cell monolayers.
We demonstrate two applications of this model in detail: (1) quantitative measurement of intestinal permeability through detection of fluorescence-labeled dextrans in serum after intraluminal injection, (2) quantitative assessment of migrated PMN across the intestinal epithelium into the gut lumen after intraluminal introduction of chemoattractants. We demonstrate feasibility of this model and provide results utilizing the iLoop in mice lacking the epithelial tight junction-associated protein JAM-A compared to controls. JAM-A has been shown to regulate epithelial barrier function as well as PMN TEpM during inflammatory responses. Our results using the iLoop confirm previous studies and highlight the importance of JAM-A in regulation of intestinal permeability and PMN TEpM in vivo during homeostasis and disease. 
The iLoop model provides a highly standardized method for reproducible in vivo studies of intestinal homeostasis and inflammation and will significantly enhance understanding of intestinal barrier function and mucosal inflammation in diseases such as IBD.

Dysregulated intestinal epithelial barrier function and immune responses are hallmarks of inflammatory bowel disease that remain poorly investigated due to a lack of physiological models. Here, we describe a mouse intestinal loop model that employs a well-vascularized and exteriorized bowel segment to study mucosal permeability and leukocyte recruitment in vivo.

Avaliação Funcional da Permeabilidade Intestinal e Migração Transepitelial de Neutrófilo em Camundongos usando um Modelo de Laço Intestinal Padronizado

The intestinal mucosa is lined by a single layer of epithelial cells that forms a dynamic barrier allowing paracellular transport of nutrients and water ...

Canine Intestinal Organoids in a Dual-Chamber Permeable Support System

The permeable support system is typically used in conjunction with traditional two-dimensional (2D) cell lines as an in vitro tool for evaluating the oral permeability of new therapeutic drug candidates. However, the use of these conventional cell lines has limitations, such as altered expression of tight junctions, partial cell differentiation, and the absence of key nuclear receptors. Despite these shortcomings, the Caco-2 and MDCK models are widely accepted and validated for the prediction of human in vivo oral permeability.
Dogs are a relevant translational model for biomedical research due to their similarities in gastrointestinal anatomy and intestinal microflora with humans. Accordingly, and in support of parallel drug development, the elaboration of an efficient and accurate in vitro tool for predicting in vivo drug permeability characteristics both in dogs and humans is highly desirable. Such a tool could be the canine intestinal organoid system, characterized by three-dimensional (3D), self-assembled epithelial structures derived from adult stem cells.
The (1) Permeable Support Seeding Protocol describes the experimental methods for dissociating and seeding canine organoids in the inserts. Canine organoid isolation, culture, and harvest have been previously described in a separate set of protocols in this special issue. Methods for general upkeep of the canine intestinal organoid monolayer are discussed thoroughly in the (2) Monolayer Maintenance Protocol. Additionally, this protocol describes methods to assess the structural integrity of the monolayer via transepithelial electrical resistance (TEER) measurements and light microscopy. Finally, the (3) Permeability Experimental Protocol&#160;describes the tasks directly preceding an experiment, including in vitro validation of experimental results.
Overall, the canine organoid model, combined with a dual-chamber cell culture technology, overcomes limitations associated with 2D experimental models, thereby improving the reliability of predictions of the apparent oral permeability of therapeutic drug candidates both in the canine and human patient.

Here, we present a protocol describing the culture of canine intestinal organoids in a dual-chamber, permeable support system. Organoid seeding in the permeable supports, the monolayer maintenance, and subsequent drug permeability experiments are described.

Organoides intestinais caninos em um sistema de suporte permeável de câmara dupla

The permeable support system is typically used in conjunction with traditional two-dimensional (2D) cell lines as an in vitro tool for evaluating the oral ...