Financiamento fornecido pelo NIH (1 K08 DK080221-01) e fundos de desenvolvimento institucional Vanderbilt.

Parte 1: Lesão Modelo de Colite <ol><li> Peso inicial deve ser obtido para cada rato antes do início do tratamento DSS. </li><li> Fazer uma de 3% (w / v) Sulfato de Dextran solução de sal de sódio em água e filtrar com um filtro de 0,45 mM de acetato de celulose. </li><li> Substituir a água potável na gaiola do rato com a solução DSS 3% por quatro dias. Os ratos não devem ter acesso a qualquer outra fonte de água (ou seja, a exclusão dicas colocados em sistemas de rega automática). </li><li> No dia quatro, substitua a solução DSS com água por mais três dias, permitindo alguma recuperação do cólon epiteliais. Os ratos devem ser pesados ​​no dia quatro, a fim de quantificar conseqüências sistêmicas da colite. Perda de peso é comum com ferimentos graves. </li><li> No dia 7, pesar e sacrifício dos ratos. Ratos podem ser sacrificados por overdose inalatória de isoflurano, ou outros institucionalmente, IACUC métodos aprovados. </li></ol> Parte 2: Necropsia e Colheita de Colon <ol><li> Expor o lado ventral do rato e pernas seguro para garantir o acesso livre para o abdômen. Molhar o abdômen completamente com álcool 70%. </li><li> Segure a linha média do abdómen com uma pinça e estender para cima, assim tenting a pele. Use uma tesoura de ponta fina para o abdômen inciso expondo o conteúdo abdominal. Estender a incisão para a ponta do apêndice xifóide na linha média e depois estender ao longo do aspecto inferior das margens costal, bilateralmente. </li><li> Identificar o intestino delgado, ceco e cólon. Dissecar cuidadosamente / provocação do cólon a partir do mesentério circundante. Transecto do cólon profundamente na pelve, para libertar o cólon distal e reto. Transecto os dois pontos na margem colonocecal para libertar o cólon proximal. Cuidados devem ser tomados durante este processo para não danificar o colon como a limpeza do cólon será problemático se ocorrer perfuração. </li><li> Utilizando uma agulha 20G alimentação e seringa de 10 ml, entubar e lave o cólon com gelado PBS até que o eluido está completamente limpa de fezes. </li><li> Neste ponto, se a análise macroscópica com um microscópio de dissecação é desejado, os dois pontos podem ser fixados como &quot;lingüiça&quot;. Se a análise histológica é apenas desejável do que prosseguir para a Parte 4 &quot;Fazendo Rolls Suíça para a análise histológica de colite aguda&quot;. </li></ol> Parte 3: Processamento como &quot;Lingüiça&quot; para análise macroscópica de todo o cólon <ol><li> É importante manter a correta orientação do cólon, portanto, manter a extremidade distal do cólon mais próximo do operador. Corte dois pedaços de sutura não absorvível (SP116 1,5 seda trançada métricas), uma polegada de aproximadamente 1 em comprimento, os outros 2 polegadas. </li><li> Use a peça 2 polegada de sutura para amarrar a extremidade distal mais próximo à margem quanto possível, mantendo uma boa vedação. </li><li> Coloque uma agulha 20G alimentação contendo 5 ml de tampão fosfato 10% de formol na extremidade proximal do cólon. Vagamente empate a parte restante da sutura imediatamente proximal ao bulbo da agulha de alimentação. Segure firmemente os dois pontos no bulbo da agulha de alimentação e infundir formalina até o cólon é expandido. Apertar o nó na sutura que você retire a agulha de alimentação, deixando a infusão de cólon, expandiu como um &quot;salsicha&quot;. </li><li> Encha um tubo de 15 ml com 10% de fosfato tamponada de formalina e coloque os dois pontos no tubo. Correção para 24 horas. </li><li> Deitar fora formalina e substituir com EtOH 70% para um 24 horas adicionais. (Colons podem ser armazenados em EtOH 70% indefinidamente à temperatura ambiente.) </li><li> Remova os dois pontos do tubo cônico e cortou as cordas em cada extremidade com um bisturi, tomando cuidado para não danificar o colon. Lembre-se que a extremidade distal tem o maior pedaço de corda. Corte longitudinal do distal para extremidade proximal do cólon para que forme uma longa folha. Neste ponto, o cólon pode ser visto sob um microscópio de dissecação. </li></ol> Parte 4: Making Rolls Suíça para a análise histológica de colite aguda <ol><li> É importante manter a correta orientação do cólon, portanto, manter a extremidade distal do cólon mais próximo do operador. </li><li> Meça o comprimento do cólon. Esta métrica é um indicador da gravidade da lesão. Colite aumenta edema e encurta o comprimento do cólon em geral. </li><li> Usando uma tesoura de ponta fina, inciso longitudinalmente de distal para proximal final do cólon. Use uma pinça bem cotado para agarrar a borda da incisão e aberto lateralmente trabalhando o seu caminho distalmente-&gt; proximalmente, assim, mostrando o cólon como uma folha plana. </li><li> Rolando o cólon exige um par de fórceps e uma técnica de duas mãos. Segure a borda da margem distal com uma pinça. Proceder à seqüencialmente rolo do cólon através da rotação e liberando a pinça de prosseguir para a margem proximal. Gerando assim uma espiral com uma terceira dimensão ou &quot;Swiss roll&quot;.Para manter a forma rolada, segure o rolo com firmeza com uma pinça e transectos com uma agulha 27G1 / 2. Segura a agulha, dobrando a agulha que sai do rolo. </li><li> Coloque o rolo em uma fita de tecido devidamente rotulados e coloque em um frasco de 10% de fosfato tamponada de formol em temperatura ambiente por 24 horas para garantir a fixação do tecido. </li><li> Deitar fora formalina e substituir com EtOH 70% para um 24 horas adicionais. (Colons podem ser armazenados em EtOH 70% indefinidamente à temperatura ambiente.) </li><li> Uma vez que a amostra foi corrigido, ele pode ser incluído em parafina, seccionado e montado em lâminas para análise histológica. </li></ol> Parte 5: Resultados Representante O modelo DSS para a colite aguda permite ao pesquisador obter, corrigir e analisar dois pontos que a colite aguda modelos. Quando o rolo suíço é cortado e montado, ele deve formar uma fatia representativa de todo o cólon, se rolou corretamente (Figura 1). O rolo montado podem ser marcadas com H &amp; E, a fim de determinar a extensão dos danos para o cólon, desde o final (para dentro) distal até o final (fora) proximal (Figura 2). Imunohistoquímica também pode ser realizada no rolo suíço para identificar e quantificar infiltrados inflamatórios. Se o método de lingüiça foi realizado corretamente, os dois pontos fixos será dilatada e toda a superfície da mucosa pode ser facilmente manipulado e visto sob o microscópio de dissecação (Figura 3). <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/1652/1652fig1.jpg"><img src="/files/ftp_upload/1652/1652fig1tmb.jpg" alt="Figura 1" border="0" /></a> Figura 1. Corretamente executados &quot;Swiss roll&quot;. (A) Os dois pontos são rolados do distal para proximal final, seccionado com uma agulha e garantidos por dobrar a ponta da agulha. Em seguida, é colocada em um cassete de tecido para fixação. (B) H &amp; E manchada seção 5 mM de um rocambole feito a partir do cólon de um rato tratados com DSS (d = cólon distal p = cólon proximal). <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/1652/1652fig2.jpg"><img src="/files/ftp_upload/1652/1652fig2tmb.jpg" alt="Figura 2" border="0" /></a> Figura 2. Colons DSS tratados mostrar sinais de colite aguda. Inflamação e danos cripta são aparentes no cólon DSS-tratados em comparação com um controle de água tratada. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/1652/1652fig3.jpg"><img src="/files/ftp_upload/1652/1652fig3tmb.jpg" alt="Figura 3" border="0" /></a> Figura 3. Um exemplo de uma &quot;salsicha&quot;. A salsicha infundido com formalina e completamente expandidas. Um leve ângulo estará presente secundária à curvatura natural do cólon. A salsicha aberta deve estar nivelado.

<ol>
	<li>Okayasu, I. <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+method+in+the+induction+of+reliable+experimental+acute+and+chronic+ulcerative+colitis+in+mice.">A novel method in the induction of reliable experimental acute and chronic ulcerative colitis in mice.</a> Gastroenterology. 98 (3), 694-702 (1990).</li><li>Martinez, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Deletion+of+Mtgr1+sensitizes+the+colonic+epithelium+to+dextran+sodium+sulfate-induced+colitis.">Deletion of Mtgr1 sensitizes the colonic epithelium to dextran sodium sulfate-induced colitis.</a> Gastroenterology. 131 (2), 579-588 (2006).</li><li>Moolenbeek, C., Ruitenberg, E. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+"Swiss+roll":+a+simple+technique+for+histological+studies+of+the+rodent+intestine.">The "Swiss roll": a simple technique for histological studies of the rodent intestine.</a> Lab Anim. 15 (1), 57-59 (1981).</li><li>Mahler, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+susceptibility+of+inbred+mouse+strains+to+dextran+sulfate+sodium-induced+colitis.">Differential susceptibility of inbred mouse strains to dextran sulfate sodium-induced colitis.</a> Am J Physiol. 274, G544-551 (1998).</li><li>Aharoni, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immunomodulatory+therapeutic+effect+of+glatiramer+acetate+on+several+murine+models+of+inflammatory+bowel+disease.">Immunomodulatory therapeutic effect of glatiramer acetate on several murine models of inflammatory bowel disease.</a> J Pharmacol Exp Ther. 318 (1), 68-78 (2006).</li><li>Hahm, K. B. <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+transforming+growth+factor+beta+signalling+in+the+intestine+contributes+to+tissue+injury+in+inflammatory+bowel+disease.">Loss of transforming growth factor beta signalling in the intestine contributes to tissue injury in inflammatory bowel disease.</a> Gut. 49 (2), 190-198 (2001).</li><li>Green, B. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adrenergic+modulation+of+Escherichia+coli+O157:H7+adherence+to+the+colonic+mucosa.">Adrenergic modulation of Escherichia coli O157:H7 adherence to the colonic mucosa.</a> Am J Physiol Gastrointest Liver Physiol. 287 (6), G1238-1246 (2004).</li><li>Dieleman, L. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chronic+experimental+colitis+induced+by+dextran+sulphate+sodium+(DSS)+is+characterized+by+Th1+and+Th2+cytokines.">Chronic experimental colitis induced by dextran sulphate sodium (DSS) is characterized by Th1 and Th2 cytokines.</a> Clin Exp Immunol. 114 (3), 385-391 (1998).</li></ol>

Experimentos em animais foram realizados de acordo com as diretrizes e regulamentos estabelecidos pela Vanderbilt IACUC.

Este protocolo pode ser modificado para modelo de lesão aguda, lesão de reparação, ou crônica processos de lesão do cólon. Modificação lesão aguda: DSS ad lib tratamento para 4-6 dias, seguido pelo sacrifício imediato Lesão-Modificação: Lesões com 4-6 dias de tratamento DSS seguido por período de recuperação de 3-4 dias e sacrifício (como descrito no protocolo acima). Modificação colite crônica: Os ratos são colocados em três ciclos de cinco dias de DSS 3% com 16 dias de recuperação entre cada ciclo. Os ratos são sacrificados após o período de descanso final de 16 dias. Há várias questões que os pesquisadores precisam estar conscientes de com este modelo: <ol><li> Variabilidade no local da lesão: Em nossas mãos, vemos um padrão de lesão predominantemente distal, com relativa preservação do cólon proximal e ceco. Outros relataram predominância mais proximal ao padrão de lesão. </li><li> Variabilidade ambiental. Existe uma variabilidade ambiental significativo. Isto é provável, em parte, devido a diferenças na microflora intestinal, dieta e outras considerações ambientais. </li><li> Este modelo é ineficaz se DSS de alto peso molecular é usada (ou seja, 500.000 Da). </li><li> Existe uma variabilidade considerável pressão com este modelo de 4. </li></ol> Análise bioquímica do cólon pode ser realizada através de amostras a partir das margens proximal ou distal. Dependendo da gravidade da lesão isto pode afetar sua capacidade de gerar um escore de lesão histológica. In vivo BrdU rotulagem para medir a proliferação pode ser alcançado por meio de injeção intraperitoneal de 16,7 mg / kg BrdU 2 horas antes do sacrifício seguido de processamento de IHC α-BrdU. Como uma alternativa para a &quot;salsicha&quot;, o cólon pode ser corrigido totalmente plana. Linha de fundo de um recipiente com papel Whatman Tupperware e aproveitar o papel com 10% de fosfato tamponada de formol. Dissecar o cólon conforme descrito em &quot;Parte 2: Necropsia e Colheita de Colon&quot;. Novamente, mantenha a extremidade distal do cólon mais próximo do operador. Usando uma tesoura de ponta fina, inciso longitudinalmente de distal para proximal final do cólon. Com finas pinças de ponta agarrar a borda da incisão e aberto lateralmente de trabalho, assim mostrando o cólon como uma folha plana. Transferir esta folha plana para o papel Whatman pré-embebidas. Cobrir o cólon achatada com outro pedaço de Whatman e úmido, com 10% de fosfato tamponada de formol. A Whatman deve ser completamente coberta em formalina, mas não tanto que decola do cólon. Selar a Tupperware e correção para 24 horas. Remova os dois pontos da Tupperware e colocá-lo em 10 ml de etanol 70% em um tubo de 15 ml. (Colons podem ser armazenados em EtOH 70% indefinidamente à temperatura ambiente.) Existem vários métodos para quantificar lesão colônica 5,6,7. Um método, por exemplo, usa uma escala multi-parâmetros, incluindo: inflamação extensão, o envolvimento, a regeneração, os danos cripta, ea participação de 8 por cento.

<table><tbody><tr><td>Dextran Sulfate Sodium Salt</td><td>USB Corp., Affymetrix</td><td>9011-18-1</td><td>mol wt 40,000-50,000</td></tr><tr><td>10% Buffered Formalin Phosphate</td><td>Fisher Scientific</td><td>SF100-4</td><td></td></tr><tr><td>Isoflurane, USP</td><td>Phoenix Pharmaceuticals, Inc.</td><td>NDC 57319-474-06</td><td></td></tr><tr><td>TISSUE PATH Macrosette Cassettes</td><td>Fisher Scientific</td><td>15182706</td><td></td></tr><tr><td>BD 10 ml Syringe</td><td>BD Biosciences</td><td>309604</td><td></td></tr><tr><td>Ethyl Alcohol</td><td>Pharmco-AAPER</td><td>E190</td><td>Dilute to 70% with distilled water</td></tr><tr><td>20G Straight Feeding Needle</td><td>VWR international</td><td>20068-612</td><td></td></tr><tr><td>27G1/2 PrecisionGlide Needle</td><td>BD Biosciences</td><td>305109</td><td></td></tr><tr><td>Dissecting Scissors Sharp/Blunt Tip</td><td>VWR international</td><td>82027-588</td><td></td></tr><tr><td>Waugh Forceps</td><td>VWR international</td><td>82027-428</td><td></td></tr><tr><td>Non-absorbable Suture </td><td>LOOK Surgical</td><td>SP116</td><td></td></tr><tr><td>Whatman Blotting Paper</td><td>VWR international</td><td>28298-020</td><td>Cut as needed</td></tr><tr><td>Nalgene Surfactant-Free Cellulose Acetate (SFCA) Filter</td><td>Cole-Parmer</td><td>EW-06731-2</td><td></td></tr><tr><td>Carbon fiber composites digital caliper</td><td>Fisher Scientific</td><td>15-007-958</td><td></td></tr></tbody></table>

murine colitis modeling using dextran sulfate sodium (dss)

Colite pode ocorrer por infecções virais ou bacterianas, insulto isquêmico, ou doenças auto-imunes; Colite Ulcerativa e mais notadamente a variante do cólon da doença de Crohn - Colite de Crohn. Colite aguda podem apresentar dor abdominal e distensão, má absorção, diarréia, hematoquezia e muco nas fezes. Estamos começando a entender as complexas interações entre o meio ambiente, genética e disfunção da barreira epitelial em modelos de doença inflamatória intestinal e animal de colite têm sido essenciais para fazer avançar a nossa compreensão da doença. Um modelo popular envolve completando a água potável de camundongos com sulfato de baixo peso molecular de sódio Dextran (DSS), resultando em danos epiteliais e uma resposta robusta inflamatória no cólon de vários dias<sup&gt; 1</sup&gt;. Variações dessa abordagem pode ser usada para modelo de lesão aguda, lesão aguda seguida de reparo, e ciclos repetidos de DSS intercaladas com recuperação de modelagem doenças inflamatórias crônicas<sup&gt; 2</sup&gt;. Após um tratamento de quatro dias de DSS 3% em água potável, os camundongos mostram sinais de colite aguda, incluindo a perda de peso, sangue nas fezes e diarréia. Os ratos são sacrificados na conclusão do curso de tratamento e em dois pontos necropsia dissecados são processados ​​e pode ser &quot;enrolado suíço&quot;<sup&gt; 3</sup&gt; Para permitir a análise microscópica de todo o cólon ou infundido com formol como &quot;lingüiça&quot; para permitir a análise macroscópica. Tecido é então embebidos em parafina, seccionados e corados para análise histológica.

Watch this Scientific Journal Video about Murine Colitis Modeling using Dextran Sulfate Sodium DSS at JoVE.com

Murine Colitis Modeling using Dextran Sulfate Sodium DSS

Dextran sulfato de sódio (DSS), administrada na água de beber é um modelo de lesão inflamatória estabelecida murino de colite aguda. Este protocolo descreve o método para o tratamento DSS ea preparação dos tecidos.

Modelagem Colite murino utilizando Dextran Sulfato de Sódio (DSS)

Colitis can occur from viral or bacterial infections, ischemic insult, or autoimmune disorders; most notably Ulcerative Colitis and the colonic variant of ...

murine-colitis-modeling-using-dextran-sulfate-sodium-dss

Nanyang Technological University

Research

JoVE Journal

Biology

Murine Colitis Modeling using Dextran Sulfate Sodium (DSS)

49.8K visualizações.  Vanderbilt University. Dextran sulfato de sódio (DSS), administrada na água de beber é um modelo de lesão inflamatória estabelecida murino de colite aguda. Este protocolo descreve o método para o tratamento DSS ea preparação dos tecidos.

Vídeo: Murine Colitis Modeling using Dextran Sulfate Sodium DSS

Modeling Colitis-Associated Cancer with Azoxymethane (AOM) and Dextran Sulfate Sodium (DSS)

Individuals with inflammatory bowel disease (IBD), such as Crohn's disease (CD) or ulcerative colitis (UC) are at increased risk of developing colorectal cancer (CRC) over healthy individuals. This risk is proportional to the duration and extent of disease, with a cumulative incidence as high as 30% in individuals with longstanding UC with widespread colonic involvement.1 Colonic dysplasia in IBD and colitis associated cancer (CAC) are believed to develop as a result of repeated cycles of epithelial cell injury and repair while these cells are bathed in a chronic inflammatory cytokine milieu.2 While spontaneous and colitis-associated cancers share the quality of being adenocarcinomas, the sequence of underlying molecular events is believed to be different.3 This distinction argues the need for specific animal models of CAC.
Several mouse models currently exist for the study of CAC. Dextran sulfate sodium (DSS), an agent with direct toxic effects on the colonic epithelium, can be administered in drinking water to mice in multiple cycles to create a chronic inflammatory state. With sufficient duration, some of these mice will develop tumors.4 Tumor development is hastened in this model if administered in a pro-carcinogenic setting. These include mice with genetic mutations in tumorigenesis pathways (APC, p53, Msh2), as well as mice pre-treated with genotoxic agents (azoxymethane [AOM], 1,2-dimethylhydrazine [DMH]).5 
The combination of DSS with AOM as a model for colitis associated cancer has gained popularity for its reproducibility, potency, low price, and ease of use. Though they have a shared mechanism, AOM has been found to be more potent and stable in solution than DMH. While tumor development in other models generally requires several months, mice injected with AOM and subsequently treated with DSS develop adequate tumors in as little as 7-10 weeks.6, 7 Finally, AOM and DSS can be administered to mice of any genetic background (knock out, transgenic, etc.) without cross-breeding to a specific tumorigenic strain. Here, we demonstrate a protocol for inflammation-driven colonic tumorigenesis in mice utilizing a single injection of AOM followed by three seven-day cycles of DSS over a 10 week period. This model induces tumors with histological and molecular changes closely resembling those occurring in human CAC and provides a highly valuable model for the study of oncogenesis and chemoprevention in this disease.8

Modeling Colitis-Associated Cancer with Azoxymethane AOM and Dextran Sulfate Sodium DSS

We demonstrate a protocol in which administration of the genotoxic agent azoxymethane (AOM) followed by three cycles of the pro-inflammatory agent dextran sulfate sodium (DSS) rapidly and consistently generates colon tumors in mice with morphologic and molecular similarities to those seen in human colitis-associated cancer.

Câncer de modelagem Colite Associada com Azoximetano (OMA) e sulfato de sódio Dextran (DSS)

Individuals with inflammatory bowel disease (IBD), such as Crohn's disease (CD) or ulcerative colitis (UC) are at increased risk of developing colorectal ...

Medicina

DNBS/TNBS Colitis Models: Providing Insights Into Inflammatory Bowel Disease and Effects of Dietary Fat

Inflammatory Bowel Diseases (IBD), including Crohn&#39;s Disease and Ulcerative Colitis, have long been associated with a genetic basis, and more recently host immune responses to microbial and environmental agents. Dinitrobenzene sulfonic acid (DNBS)-induced colitis allows one to study the pathogenesis of IBD associated environmental triggers such as stress and diet, the effects of potential therapies, and the mechanisms underlying intestinal inflammation and mucosal injury. In this paper, we investigated the effects of dietary n-3 and n-6 fatty acids on the colonic mucosal inflammatory response to DNBS-induced colitis in rats. All rats were fed identical diets with the exception of different types of fatty acids [safflower oil (SO), canola oil (CO), or fish oil (FO)] for three&#160;weeks prior to exposure to intrarectal DNBS. Control rats given intrarectal ethanol continued gaining weight over the 5 day study, whereas, DNBS-treated rats fed lipid diets all lost weight with FO and CO fed rats demonstrating significant weight loss by 48&#160;hr and rats fed SO by 72&#160;hr. Weight gain resumed after 72&#160;hr post DNBS, and by 5 days post DNBS, the FO group had a higher body weight than SO or CO groups. Colonic sections collected 5&#160;days post DNBS-treatment showed focal ulceration, crypt destruction, goblet cell depletion, and mucosal infiltration of both acute and chronic inflammatory cells that differed in severity among diet groups. The SO fed group showed the most severe damage followed by the CO, and FO fed groups that showed the mildest degree of tissue injury. Similarly, colonic myeloperoxidase (MPO) activity, a marker of neutrophil activity was significantly higher in SO followed by CO fed rats, with FO fed rats having significantly lower MPO activity. These results demonstrate the use of DNBS-induced colitis, as outlined in this protocol, to determine the impact of diet in the pathogenesis of IBD.

DNBS/TNBS induced colitis offers an alternative and inexpensive method to study the pathobiology of inflammatory bowel disease. The protocol discussed in this paper outlines the successful application of DNBS to induce colitis in mice and rats and allows one to thoroughly study host-mediated intestinal responses.

DNBS / TNBS Colite Modelos: elucidando sua Doença Inflamatória Intestinal e Efeitos de gordura na dieta

Inflammatory Bowel Diseases (IBD), including Crohn&#39;s Disease and Ulcerative Colitis, have long been associated with a genetic basis, and more recently ...

Investigating Intestinal Inflammation in DSS-induced Model of IBD

Inflammatory bowel disease (IBD) encompasses a range of intestinal pathologies, the most common of which are ulcerative colitis (UC) and Crohn's Disease (CD). Both UC and CD, when present in the colon, generate a similar symptom profile which can include diarrhea, rectal bleeding, abdominal pain, and weight loss.1 Although the pathogenesis of IBD remains unknown, it is described as a multifactorial disease that involves both genetic and environmental components.2
There are numerous and variable animal models of colonic inflammation that resemble several features of IBD. Animal models of colitis range from those arising spontaneously in susceptible strains of certain species to those requiring administration of specific concentrations of colitis-inducing chemicals, such as dextran sulphate sodium (DSS). Chemical-induced models of gut inflammation are the most commonly used and best described models of IBD. Administration of DSS in drinking water produces acute or chronic colitis depending on the administration protocol.3 Animals given DSS exhibit weight loss and signs of loose stool or diarrhea, sometimes with evidence of rectal bleeding.4,5 Here, we describe the methods by which colitis development and the resulting inflammatory response can be characterized following administration of DSS. These methods include histological analysis of hematoxylin/eosin stained colon sections, measurement of pro-inflammatory cytokines, and determination of myeloperoxidase (MPO) activity, which can be used as a surrogate marker of inflammation.6
The extent of the inflammatory response in disease state can be assessed by the presence of clinical symptoms or by alteration in histology in mucosal tissue. Colonic histological damage is assessed by using a scoring system that considers loss of crypt architecture, inflammatory cell infiltration, muscle thickening, goblet cell depletion, and crypt abscess.7 Quantitatively, levels of pro-inflammatory cytokines with acute inflammatory properties, such as interleukin (IL)-1&beta;, IL-6 and tumour necrosis factor (TNF)-&alpha;,can be determined using conventional ELISA methods. In addition, MPO activity can be measured using a colorimetric assay and used as an index of inflammation.8
In experimental colitis, disease severity is often correlated with an increase in MPO activity and higher levels of pro-inflammatory cytokines. Colitis severity and inflammation-associated damage can be assessed by examining stool consistency and bleeding, in addition to assessing the histopathological state of the intestine using hematoxylin/eosin stained colonic tissue sections. Colonic tissue fragments can be used to determine MPO activity and cytokine production. Taken together, these measures can be used to evaluate the intestinal inflammatory response in animal models of experimental colitis.

Experimental models of inflammatory bowel disease have allowed us to examine the complex innate and adaptive immune responses associated with pathogenesis. Using histological scoring, quantification of pro-inflammatory cytokines and myeloperoxidase activity, one can begin to assess these responses seen in inflammatory bowel disease.

Investigando inflamação intestinal em DSS-induzida Modelo de IBD

Inflammatory bowel disease (IBD) encompasses a range of intestinal pathologies, the most common of which are ulcerative colitis (UC) and Crohn's Disease ...

Biologia

Using Robotic Systems to Process and Embed Colonic Murine Samples for Histological Analyses

The understanding of human diseases has been greatly expanded thanks to the study of animal models. Nonetheless, histopathological evaluation of experimental models needs to be as rigorous as that applied for human samples. Indeed, drawing reliable and accurate conclusions is critically influenced by the quality of tissue section preparation. Here, we describe a protocol for histopathological analysis of murine tissues that implements several automated steps during the procedure, from the initial preparation to the paraffin embedding of the murine samples. The reduction of methodological variables through rigorous protocol standardization from automated procedures contributes to increased overall reliability of murine pathological analysis. Specifically, this protocol describes the utilization of automated processing and embedding robotic systems, routinely used for the tissue processing and paraffin embedding of human samples, to process murine specimens of intestinal inflammation. We conclude that the reliability of histopathological examination of murine tissues is significantly increased upon introduction of standardized and automated techniques.

Lack of standardization for murine tissue processing reduces the quality of murine histopathological analysis as compared to human specimens. Here, we present a protocol to perform histopathological examination of murine inflamed and uninflamed colonic tissues to show the feasibility of robotic systems routinely used for processing and embedding&#160;human samples.

Usando sistemas robóticos para processar e incorporar Colônica murino amostras para análise histológica

The understanding of human diseases has been greatly expanded thanks to the study of animal models. Nonetheless, histopathological evaluation of ...

Imunologia e Infecção

Murine Distal Colostomy, A Novel Model of Diversion Colitis in C57BL/6 Mice

Diversion colitis (DC) is a frequent clinical condition occurring in patients with bowel segments excluded from the fecal stream as a result of a diverting enterostomy. The etiology of this disease remains ill-defined but appears to differ from that of classical inflammatory bowel diseases such as Crohn's disease and ulcerative colitis. Research aimed to decipher the pathophysiological mechanisms leading to the development of this disease has been severely hampered by the lack of an appropriate murine model. This protocol generates a murine model of DC that facilitates the study of the immune system's role and its interaction with the microbiome in the development of DC. In this model using C57BL/6 animals, distal parts of the colon are excluded from the fecal stream by creating a distal colostomy, triggering the development of mild to moderate inflammation in the excluded bowel segments and reproducing the hallmark lesions of human DC with a moderate systemic inflammatory response. In contrast to the rat model, a large number of genetically-modified murine models on the C57BL/6 background are available. The combination of these animals with our model allows the potential roles of individual cytokines, chemokines, or receptors of bioactive molecules (e.g., interleukin (IL)-17; IL-10, chemokine CXCL13, chemokine receptors CXCR5 and CCR7, and the sphingosine-1-phosphate receptor 4) to be assessed in the pathogenesis of DC. The availability of congenic mouse strains on the C57BL/6 background largely facilitates transfer experiments to establish the roles of distinct cell types involved in the etiology of DC. Finally, the model offers the opportunity to assess the influences of local interventions (e.g., modification of the local microbiome or local anti-inflammatory therapy) on mucosal immunity in affected and non-affected bowel segments and the on systemic immune homeostasis.

Murine distal colostomy provides a murine model for human diversion colitis, a predominantly lymphocytic colitis in colon segment excluded from the fecal stream.

Murino colostomia Distal, um novo modelo de colite de diversão em camundongos C57BL/6

Diversion colitis (DC) is a frequent clinical condition occurring in patients with bowel segments excluded from the fecal stream as a result of a ...

Systematic Scoring Analysis for Intestinal Inflammation in a Murine Dextran Sodium Sulfate-Induced Colitis Model

Murine colitis models are tools that are extensively employed in studies focused on understanding the pathobiology of inflammatory intestinal disorders. However, robust standards for objective and reproducible quantification of disease severity remain to be defined. Most colitis analysis methods rely on limited histological scoring of small segments of intestine, leading to partial or biased analyses. Here, we combine high-resolution image acquisition and longitudinal analysis of the entire colon to quantify intestinal injury and ulceration in the dextran sodium sulfate (DSS) induced model of murine colitis. This protocol allows for the generation of objective and reproducible results without extensive user training. Here, we provide comprehensive details on sample preparation and image analysis using examples of data from DSS induced colitis. This method can be easily adapted to other models of murine colitis that have significant inflammation associated with mucosal injury. We demonstrate that the fraction of inflamed/injured and eroded/ulcerated mucosa relative to the complete length of the colon closely parallels clinical findings such as weight loss amid DSS-induced disease progression. This histological protocol provides a reliable time and cost-effective aid to standardize analyses of disease activity in an unbiased way in DSS colitis experiments.

Systematic scoring of intestinal inflammation using a free computer-assisted system is a powerful tool to quantitatively compare histopathological changes in colitis models characterized by the presence of ulcers and inflammatory changes. Histological colitis score evaluation strengthens clinical observations and facilitates data interpretation.

Análise sistemática de pontuação para inflamação intestinal em um modelo de colite induzida por sulfato de sódio murine dextran

Murine colitis models are tools that are extensively employed in studies focused on understanding the pathobiology of inflammatory intestinal disorders. ...

Murine Appendectomy Model of Chronic Colitis Associated Colorectal Cancer by Precise Localization of Caecal Patch

The human appendix has been recently implicated to play important biological roles in the pathogenesis of various complex diseases, such as colorectal cancer, inflammatory bowel disease, and Parkinson&#8217;s disease. To study the function of the appendix, a gut disease-associated murine appendectomy model has been established and its step-by-step protocol is described here. This report introduces a facile protocol for caecal patch removal in mice followed by the chemical induction of chronic colitis-associated colorectal cancer using a combination of dextran sulfate sodium (DSS) and azoxymethane (AOM). IgA specific cells and IgA concentration were significantly reduced upon removal of the caecal patch in male C57BL/6 mice&#160;compared to those in the sham group. Simultaneously administering 2% DSS and AOM resulted in nearly 80% mice survival in both sham and appendectomy groups without significant body weight loss. Histological results confirmed colonic inflammation and different degrees of adenocarcinoma. This model can be used for the study of the functional role of the appendix in maintaining gut microbiota homeostasis and pathogenesis of gut colitis and malignancies, as well as for the potential development of drug targeting therapies.

The presented protocol describes a facile surgical removal of the appendix (caecal patch) in a mouse followed by the induction of inflammatory bowel disease-associated colorectal cancer. This murine appendectomy model enables investigation of the biological role of the appendix in the pathogenesis of human gastrointestinal disease.

Modelo de apendicectomia Murina de colite crônica câncer colorretal associado por localização precisa do remendo de Caecal

The human appendix has been recently implicated to play important biological roles in the pathogenesis of various complex diseases, such as colorectal ...

Evaluation and Quantification of Micro Epithelial Gaps in the Colonic Mucosa using Immunofluorescence Staining

Epithelial cells lining the intestinal mucosa create a physical barrier that separates the luminal content from the interstitium. Epithelial barrier impairment has been associated with the development of various pathologies such as inflammatory bowel diseases (IBD). In the inflamed mucosa, superficial erosions or micro-erosions that corrupt epithelial monolayers correspond to sites of high permeability. Several mechanisms have been implicated in the formation of micro-erosions including cell shedding and apoptosis. These micro-erosions often represent microscopic epithelial gaps randomly distributed in the colon. Visualization and quantification of those epithelial gaps has emerged as an important tool to investigate intestinal epithelial barrier function. Here, we describe a new method to visualize the specific location of where transcellular and paracellular permeability is enhanced in the inflamed colonic mucosa. In this assay, we apply a 10 kDa fluorescent dye conjugated to a lysine fixable dextran to visualize high permeability regions (HPR) in the colonic mucosa. Additional use of cell death markers revealed that HPR encompass apoptotic foci where epithelial extrusion/shedding occurs. The protocol described here provides a simple but effective approach to visualize and quantify micro-erosions in the intestine, which is a very useful tool in disease models, in which the intestinal epithelial barrier is compromised.

Here, we describe a new method to visualize the specific location of where transcellular and paracellular permeability is enhanced in the inflamed colonic mucosa. In this assay, we apply a 10 kDa fluorescent dye conjugated to a lysine fixable dextran to visualize high permeability regions (HPR) in the colonic mucosa.

Epithelial cells lining the intestinal mucosa create a physical barrier that separates the luminal content from the interstitium. Epithelial barrier ...

Hematoxylin and Eosin Staining to Assess Colon Damage in DSS-Induced Colitis

Source: Du, Y., et al. <a href="https://app-jove-com.remotexs.ntu.edu.sg/v/58668">Effects of Taste Signaling Protein Abolishment on Gut Inflammation in an Inflammatory Bowel Disease Mouse Model.</a> J. Vis. Exp. (2018)
This video demonstrates the hematoxylin and eosin (H&#38;E) staining method to evaluate colon damage in a murine model of DSS-induced colitis &#8212; an inflammatory bowel disease. Upon isolating the colon from a DSS-treated mouse and obtaining sections of the tissue, H&#38;E staining of the sections helps identify the inflammation-mediated tissue damage.

Coloração de hematoxilina e eosina para avaliar danos no cólon na colite induzida por DSS

Source: Du, Y., et al. Effects of Taste Signaling Protein Abolishment on Gut Inflammation in an Inflammatory Bowel Disease Mouse Model. J. Vis. Exp. ...

JoVE Encyclopedia of Experiments

Imunologia

Resposta Imune

Interação Hospedeiro-Patógeno

A Technique to Generate a Murine Model of Dextran Sulfate Sodium-Induced Colitis

Source: Du, Y., et al. <a href="https://app-jove-com.remotexs.ntu.edu.sg/v/58668">Effects of Taste Signaling Protein Abolishment on Gut Inflammation in an Inflammatory Bowel Disease Mouse Model.</a> J. Vis. Exp. (2018)
This video demonstrates a technique to generate a chemical-induced murine model of colitis &#8212; an inflammatory bowel disease. The mouse is allowed to consume a dextran sodium sulfate (DSS) solution for an adequate duration. Upon consumption, DSS damages the mucus and epithelial layer barrier in the colon, allowing gut microbes to enter the underlying tissue &#8212; where they are sensed by the resident immune cells to mediate an exaggerated immune response, resulting in inflammation.