Name: analyzing beneficial effects of nutritional supplements on intestinal epithelial barrier functions during experimental colitis
Uploaded: 2017-01-05T15:00:00
Description: Watch this Scientific Journal Video about Analyzing Beneficial Effects of Nutritional Supplements on Intestinal Epithelial Barrier Functions During Experimental Colitis at JoVE.com

This work was supported by grants from the Mexican Council for Science and Technology (Conacyt, 207268 and 233395 to Michael Schnoor). KFCO is a recipient of a Conacyt stipend (396260) to obtain an MSc degree.

All animal experiments have been approved by the Institutional Animal Care and Use Committee of Cinvestav.
1. Preparation of DSS Drinking Water and the Induction of Colitis
<ol>
	<li>Prepare a 3.5% w/v dextran sulfate sodium (DSS) solution in autoclaved drinking water. DSS dissolves easily and it is not required to filter the final solution. 
	NOTE: 7 days of DSS treatment induces severe colitis. If inducing mild colitis, 3 - 4 days of treatment are recommended. As long as the DSS drinking water stays clear...

<ol>
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In order to use nutritional supplements in clinical studies, the benefits and safety of such supplements must be carefully evaluated in vivo in animal studies. In the case of colitis, several appropriate animal models that resemble the clinical signs of IBD have been established, including chemical models using DSS, TNBS, or acetic acid; knock-out (KO) models such as IL10-KO; and immune-cell-mediated colitis using adoptive T-cell transfer19-21. The DSS model of colitis is a rapid and reliable method o...

Colitis is an inflammatory condition of the colon that can cause diarrhea and abdominal pain. Colitis can be acute, in response to infection or to stress, or it can develop as a chronic disease, such as in ulcerative colitis (UC), which belongs to the group of inflammatory bowel diseases (IBD). Although the clinical signs of UC have been well described, the pathogenesis is still poorly understood1. It is accepted among experts that UC is a multifactorial disease, with genetic mutations and aberrant immune responses playing a major role2. However, environmental factors, such as style of living and nutrition, also contribute to disease development and progression3.
Unfortunately, IBD is not curable, but there are many treatment options that aim to alleviate clinical symptoms. Current treatments include anti-inflammatory drugs, such as sulfasalazine and corticosteroids; immunosuppressants, such as azathioprine; monoclonal antibodies that capture pro-inflammatory cytokines, such as tumor necrosis factor-&#945; (TNF-&#945;), or block adhesion molecules, such as integrins, to reduce excessive leukocyte recruitment; and inhibitors that target kinases that trigger pro-inflammatory pathways, such as Janus kinase (JAK)4. Not all patients respond to all treatments, so therapeutic strategies must be individualized5. Furthermore, most of these therapeutic drugs interfere with the metabolism and immune responses, often causing severe side effects. For this reason, alternative treatment options have been investigated.
Alternative treatments include probiotics and nutritional supplements, which have been applied in animal models and clinical trials with varying levels of success6,7. We recently found that the application of different single nutritional supplements, such as anti-oxidative vitamins or &#969;3-poly-unsaturated fatty acids (PUFAs), is inferior to the application of a combination of such supplements in alleviating colitis and cardiovascular disease symptoms8,9. These studies were performed in mice, so clinical studies must be performed in humans to determine whether these findings will also be applicable to humans. Before clinical studies are initiated, the effectiveness and safety of new treatment options must be evaluated in animal models.
For IBD, the dextran sulfate sodium (DSS) model has been widely used to study the mechanisms of disease development and the beneficial effects of drugs and nutritional supplements6,10. In most studies, only an acute disease over a time period of seven days is induced; nevertheless, the clinical signs observed in these animals closely resemble those observed in IBD patients (i.e., bloody diarrhea, weight loss, epithelial dysfunction, and immune cell infiltration)10. DSS induces erosions in the mucosa, resulting in barrier dysfunction and in increased intestinal epithelial permeability11. The exact mechanism remains unknown. However, a study suggests that DSS interacts with medium chain-length fatty acids to form nano-lipocomplexes that are able to enter epithelial cells and to induce inflammatory signaling pathways12. In this article, we describe in detail how colitis is induced and analyzed in mice, how nutritional supplements are applied by gavage to ensure a constant dosage in each animal, and how the effects of such supplements on various colitis symptoms are examined.

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			<td height="21" style="height:21px;width:439px;">0.3% of gelatin&#160;</td>
			<td style="width:184px;">Bioxon</td>
			<td style="width:139px;">158</td>
			<td style="width:191px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">10% formaldehyde</td>
			<td style="width:184px;">J.T. Baker</td>
			<td style="width:139px;">2106-03</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">96-well plate with flat bottom</td>
			<td style="width:184px;">Corning</td>
			<td style="width:139px;">3368</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Absolute ethanol&#160;</td>
			<td style="width:184px;">J.T. Baker</td>
			<td style="width:139px;">9000-03</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Absolute xylene</td>
			<td style="width:184px;">J.T. Baker</td>
			<td style="width:139px;">9490-03</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">ABTS</td>
			<td style="width:184px;">Sigma Aldrich</td>
			<td style="width:139px;">H5882</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Bovine Serum Albumin</td>
			<td style="width:184px;">Sigma-Aldrich</td>
			<td style="width:139px;">9048-46-8</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">ColoScreen</td>
			<td style="width:184px;">Helena Laboratories</td>
			<td style="width:139px;">5072</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Corabion (Kindly provided by Merck, Naucalpan, Mexico)</td>
			<td style="width:184px;">Merck</td>
			<td style="width:139px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Dextran Sulfate Sodium Salt</td>
			<td style="width:184px;">Affymetrix</td>
			<td style="width:139px;">9011-18-1</td>
			<td style="width:191px;">(M.W. 40,000-50,000)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Dihydroethidium</td>
			<td style="width:184px;">Life Technology</td>
			<td style="width:139px;">D11347</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Eosin-Y&#160;</td>
			<td style="width:184px;">J.T. Baker</td>
			<td style="width:139px;">L087-03</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Evans blue</td>
			<td style="width:184px;">Sigma-Aldrich</td>
			<td style="width:139px;">314-13-6</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Feeding&#160; needle</td>
			<td style="width:184px;">Cadence Science Inc.</td>
			<td style="width:139px;">9921</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Glass slide rack with handle</td>
			<td style="width:184px;">Electron Microscopy</td>
			<td style="width:139px;">70312-16</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Glass Slides</td>
			<td style="width:184px;">Corning</td>
			<td style="width:139px;">2947</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Harris hematoxylin&#160;</td>
			<td style="width:184px;">Sigma-Aldrich</td>
			<td style="width:139px;">H3136</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Hexadecyltrimethyammonium (HTAB)</td>
			<td style="width:184px;">Sigma Aldrich</td>
			<td style="width:139px;">H6269</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Histosette (Embedding cassette)</td>
			<td style="width:184px;">Simport</td>
			<td style="width:139px;">M498.2</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Hydrochloric acid 1 M</td>
			<td style="width:184px;">J.T. Baker</td>
			<td style="width:139px;">9535-62</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Hydrogen peroxide</td>
			<td style="width:184px;">Sigma Aldrich</td>
			<td style="width:139px;">H3410</td>
			<td></td>
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		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Ketamine</td>
			<td style="width:184px;">PiSA Agropecuaria</td>
			<td style="width:139px;">Q-7833-028</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Liquid paraffin&#160;</td>
			<td style="width:184px;">Paraplast</td>
			<td style="width:139px;">39501-006</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Lithium carbonate&#160;</td>
			<td style="width:184px;">Sigma-Aldrich</td>
			<td style="width:139px;">2362</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">N,N-dimethylformamide</td>
			<td style="width:184px;">J.T. Baker</td>
			<td style="width:139px;">68-12-2</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">N-acetylcysteine</td>
			<td style="width:184px;">Sigma-Aldrich</td>
			<td style="width:139px;">A9165</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Plastic cubes</td>
			<td style="width:184px;">Electron Microscopy</td>
			<td style="width:139px;">70181</td>
			<td></td>
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		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Poly-L-Lysine Solution</td>
			<td style="width:184px;">Sigma-Aldrich</td>
			<td style="width:139px;">25988-63-0</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Prism 5 statistical software</td>
			<td style="width:184px;">GraphPad Software</td>
			<td style="width:139px;">Prism 5</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Saline Solution 0.9% NaCl</td>
			<td style="width:184px;">CS PiSA</td>
			<td style="width:139px;">Q-7833-009</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Sodium citrate</td>
			<td style="width:184px;">Sigma-Aldrich</td>
			<td style="width:139px;">W302600</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Synthetic resin&#160;</td>
			<td style="width:184px;">Poly Mont</td>
			<td style="width:139px;">7987</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Taq DNA polymerase</td>
			<td style="width:184px;">Invitrogen</td>
			<td style="width:139px;">11615-010</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Tissue-tek. O.C.T Compound</td>
			<td style="width:184px;">Sakura Finetek</td>
			<td style="width:139px;">4583</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Tuberculine Syringe</td>
			<td style="width:184px;">BD Plastipak</td>
			<td style="width:139px;">305945</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Tween 20</td>
			<td style="width:184px;">Sigma-Aldrich</td>
			<td style="width:139px;">9005-64-5</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">VECTASHIELD Antifade Mounting Medium with DAPI</td>
			<td style="width:184px;">Vector Laboratories</td>
			<td style="width:139px;">H-1200</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:439px;">Xylazine</td>
			<td style="width:184px;">PiSA Agropecuaria</td>
			<td style="width:139px;">Q-7833-099</td>
			<td></td>
		</tr>
	</tbody>
</table>

analyzing beneficial effects of nutritional supplements on intestinal epithelial barrier functions during experimental colitis

Inflammatory bowel diseases (IBD), including Crohn&#39;s disease and ulcerative colitis, are chronic relapsing disorders of the intestines. They cause severe problems, such as abdominal cramping, bloody diarrhea, and weight loss, in affected individuals. Unfortunately, there is no cure yet, and treatments only aim to alleviate symptoms. Current treatments include anti-inflammatory and immunosuppressive drugs that may cause severe side effects. This warrants the search for alternative treatment options, such as nutritional supplements, that do not cause side effects. Before their application in clinical studies, such compounds must be rigorously tested for effectiveness and security in animal models. A reliable experimental model is the dextran sulfate sodium (DSS) colitis model in mice, which reproduces many of the clinical signs of ulcerative colitis in humans. We recently applied this model to test the beneficial effects of a nutritional supplement containing vitamins C and E, L-arginine, and &#969;3-polyunsaturated fatty acids (PUFA). We analyzed various disease parameters and found that this supplement was able to ameliorate edema formation, tissue damage, leukocyte infiltration, oxidative stress, and the production of pro-inflammatory cytokines, leading to an overall improvement in the disease activity index. In this article, we explain in detail the correct application of nutritional supplements using the DSS colitis model in C57Bl/6 mice, as well as how disease parameters such as histology, oxidative stress, and inflammation are assessed. Analyzing the beneficial effects of different diet supplements may then eventually open new avenues for the development of alternative treatment strategies that alleviate IBD symptoms and/or that prolong the phases of remission without causing severe side effects.

Diet Supplements Can Protect from DSS Colitis
Anti-inflammatory and anti-oxidative diet supplements, such as vitamin C, vitamin E, the nitric oxide (NO)-source L-arginine, and &#969;3-polyunsaturated fatty acids (&#969;3-PUFAs), have been used with varying success in animal models to alleviate signs of inflammatory diseases3,6,15. Malnutrition, oxidative stress, and the production of pro-inflammatory cytokines can trigge...

Watch this Scientific Journal Video about Analyzing Beneficial Effects of Nutritional Supplements on Intestinal Epithelial Barrier Functions During Experimental Colitis at JoVE.com

Analyzing Beneficial Effects of Nutritional Supplements on Intestinal Epithelial Barrier Functions During Experimental Colitis

Current treatments of inflammatory bowel diseases (IBD) aim at alleviating disease symptoms but may cause severe side effects. Thus, alternative strategies are being investigated in animal colitis models. Here, we explain how the beneficial effects of diet supplements on clinical IBD signs are analyzed in such a colitis model.

Inflammatory bowel diseases (IBD), including Crohn&#39;s disease and ulcerative colitis, are chronic relapsing disorders of the intestines. They cause ...

The overall goal of this protocol is to evaluate the effects of supplemental nutrients in a murine model of colitis induced by dextran sulfate sodium. This method can help answer key questions in the intestinal immunology field about the development of clinical science throughout the direction of the colitis model experiment. The main advantages of this technique are that it is low cost, does not require sophisticated equipment, and provides a clear analysis of the morphology of the entire colon.This method can be used to evaluate oxidative stress in the colon as a consequence of excessive neutrophil recruitment. For nutritional supplement administration by gavage, first manually restrain the mouse by the scruff, placing the tail between the third finger and the base of the thumb. Next, holding the mouse in the upright position, insert the gavage needle into the left side of the animal's mouth and carefully follow the roof of the mouth to locate the esophagus.If no resistance is encountered, advance the needle towards the stomach. Slowly deliver the entire volume of supplement, followed by careful removal of the syringe and measure the animal's body weight. Assign a score of zero to four according to the weight loss percentage, then collect a fresh stool sample and use the provided applicators to apply a thin smear of sample onto a slide from a guaiac fecal occult blood test kit.Close the cover on the front of the kit and open the back window to apply two drops of the developer solution to the back of the sample location. Read the results after 30 seconds, assigning a score of zero to four depending upon the signal strength. Then observe a second fresh stool sample to assess the stool consistency, assigning a score of zero to four as appropriate.To determine the intestinal epithelial permeability in vivo, place an anesthetized animal in the supine position and make a midline incision to expose the intestines. Locate the cecum and make a small incision in the proximal segment of the colon ascendants. Then insert a 22 gauge feeding needle and secure the needle with a common silk thread ligature.Carefully flush an abundant volume of PBS through the needle to rinse all of the feces from the colon, followed by the installation of Evans blue solution until the dye reaches the anus. After 15 minutes, flush the tube with an excess volume of PBS until the perianal washout is clear. Then excise the colon and rinse the tissue with more PBS, followed by one milliliter of six millimolar N-acetylcysteine to eliminate any dye sticking to the colonic mucus.Now cut the colon longitudinally and rinse the tissue one more time with PBS and N-acetylcysteine, then record the weight and length of the colon and place the tissue into two milliliters of N, N-dimethylformamide at room temperature with gentle agitation to extract the remaining dye, measuring the dye concentrations spectrophotometrically at 610 nanometers the following morning. After seven days of dextran sulfate sodium, or DSS-induced colitis, dissect the entire colon and record its length. For swiss rolls, open the colon longitudinally, carefully remove any fecal matter, and use a thin, round, wooden stick or fine-tipped forceps to roll the tissue with the mucosa facing inwards.Then carefully place the tissue inside an embedding cassette, followed by fixation with five milliliters of 10%formaldehyde at room temperature. It is critical to roll up the colon tightly without folding to avoid problems during the tissue sectioning, which could result in a clinical tissue damage and a false interpretation as colitis-associated damage. After 48 hours, wash the sample with tap water for 18 hours, followed by dehydration by an ethanol series.After the last absolute ethanol immersion, treat the tissue with four one-hour incubations in xylene. After the last xylene immersion, place the sample in 50 milliliters of liquid paraffin for one 17-hour and one three-hour incubation. At the end of the three hour incubation, submerge the sample in a 22 cubic millimeter square plastic mold in eight to 10 milliliters of fresh liquid paraffin for 24 hours.When the paraffin has solidified, use a microtome to acquire five micron thick tissue sections, then briefly immerse the cross-sections in a one liter water bath containing 0.3%gelatin and immediately mount the samples on glass slides treated with polylysine for H&E staining. For oxidative stress analysis, first create a barrier around the tissue using a hydrophobic pen. Next, incubate eight micron tissue cryo cross-sections in five micromolar DHE dissolved in water for 30 minutes at 37 degrees celsius in the dark.Incubation is followed by three 15-minute washes in PBS with gentle agitation at room temperature. Air dry the samples and add a drop of mounting medium to protect the fluorescence. Then observe the oxidized ethidium fluorescence on a laser scanning confocal microscope at a 40x magnification.DSS treatment leads to a continuously increasing disease activity index as expected, reaching a maximum score on day seven post-induction. Anti-inflammatory diet supplementation delays the early onset of colitis, while the protective effects are only marginal at later time points. Dietary intervention may also prevent DSS-induced increases in intestinal epithelial permeability, as well as colon length shortening.Hematoxylin and eosin staining of paraffin-embedded distal colon tissues reveals that control samples demonstrate a normal morphology, whereas animals treated with DSS exhibit the typical signs of colitis. Of note, parallel treatment with diet supplementation clearly alleviates colitis-induced morphological changes with an overall morphology similar to that of the control group. Immunofluorescence staining of the distal colon tissue also indicates that the tight inadherens junction molecules are internalized during DSS-induced colitis and that co-localization of these proteins is partly lost at crypt epithelial cell contacts.Importantly, this internalization is reduced when DSS-treated mice receive the anti-inflammatory and anti-oxidative diet supplement. Further, robust neutrophil recruitment to the colon in response to DSS-induced colitis is counteracted by diet supplementation, resulting in the concomitant amelioration of neutrophil-induced oxidative stress and a slight reduction in inflammatory cytokine production. Following this procedure, other methods like oozing chamber measurements can be performed to analyze the electrical resistance of the epithelial barrier in the colon.After its development, this technique paved the way for researchers in the field of colitis research and exploring the molecular mechanism of ulcerative colitis pathogenesis in a reproducible mouse model. After watching this video, you should have a good understanding of how to analyze the development of colitis and the beneficial effects of nutritional supplements on intestinal epithelial barrier functions. Don't forget that working with live animals requires the adherence to high ethical standards to avoid unnecessary suffering.

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Research

JoVE Journal

Medicine

Isolation of Mouse Respiratory Epithelial Cells and Exposure to Experimental Cigarette Smoke at Air Liquid Interface

Pulmonary epithelial cells can be isolated from the respiratory tract of mice and cultured at air-liquid interface (ALI) as a model of differentiated respiratory epithelium. A protocol is described for isolating and exposing these cells to mainstream cigarette smoke (CS), in order to study epithelial cell responses to CS exposure. The protocol consists of three parts: the isolation of airway epithelial cells from mouse trachea, the culturing of these cells at air-liquid interface (ALI) as fully differentiated epithelial cells, and the delivery of calibrated mainstream CS to these cells in culture. The ALI culture system allows the culture of respiratory epithelia under conditions that more closely resemble their physiological setting than ordinary liquid culture systems. The study of molecular and lung cellular responses to CS exposure is a critical component of understanding the impact of environmental air pollution on human health. Research findings in this area may ultimately contribute towards understanding the etiology of chronic obstructive pulmonary disease (COPD), and other tobacco-related diseases, which represent major global health problems.

Pulmonary epithelial cells can be isolated from the respiratory tract of mice and cultured at air-liquid interface as a model of differentiated respiratory epithelium. A protocol is described for isolating, culturing and exposing these cells to mainstream cigarette smoke, in order to study molecular responses to this environmental toxin.

Pulmonary epithelial cells can be isolated from the respiratory tract of mice and cultured at air-liquid interface (ALI) as a model of differentiated ...

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.

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

Long-Term Catheterization of the Intestinal Lymph Trunk and Collection of Lymph in Neonatal Pigs

Catheterization of the intestinal lymph trunk in neonatal pigs is a technique allowing for the long-term collection of large quantities of intestinal (central) efferent lymph. Importantly, the collection of central lymph from the intestine enables researchers to study both the mechanisms and lipid constitutes associated with lipid metabolism, intestinal inflammation and cancer metastasis, as well as cells involved in immune function and immunosurveillance. A ventral mid-line surgical approach permits excellent surgical exposure to the cranial abdomen and relatively easy access to the intestinal lymph trunk vessel that lies near the pancreas and the right ventral segment of the portal vein underneath the visceral aspect of the right liver lobe. The vessel is meticulously dissected and released from the surrounding fascia and then dilated with sutures allowing for insertion and subsequent securing of the catheter into the vessel. The catheter is exteriorized and approximately 1 L/24 hr of lymph is collected over a 7 day period. While this technique enables the collection of large quantities of central lymph over an extended period of time, the success depends on careful surgical dissection, tissue handling and close attention to proper surgical technique. This is particularly important with surgeries in young animals as the lymph vessels can easily tear, potentially leading to surgical and experimental failure. The video demonstrates an excellent surgical technique for the collection of intestinal lymph.

We present a surgical procedure to catheterize the intestinal lymph trunk in neonatal pigs to collect large quantities of lipid metabolism components from efferent lymph.

Catheterization of the intestinal lymph trunk in neonatal pigs is a technique allowing for the long-term collection of large quantities of intestinal ...

A Step by Step Protocol for Subretinal Surgery in Rabbits

Age related macular degeneration (AMD), retinitis pigmentosa, and other RPE related diseases are the most common causes for irreversible loss of vision in adults in industrially developed countries. RPE transplantation appears to be a promising therapy, as it may replace dysfunctional RPE, restore its function, and thereby vision.
Here we describe a method for transplanting a cultured RPE monolayer on a scaffold into the subretinal space (SRS) of rabbits. After vitrectomy xenotransplants were delivered into the SRS using a custom made shooter consisting of a 20-gauge metallic nozzle with a polytetrafluoroethylene (PTFE) coated plunger. The current technique evolved in over 150 rabbit surgeries over 6 years. Post-operative follow-up can be obtained using non-invasive and repetitive in vivo imaging such as spectral domain optical coherence tomography (SD-OCT) followed by perfusion-fixed histology.
The method has well-defined steps for easy learning and high success rate. Rabbits are considered a large eye animal model useful in preclinical studies for clinical translation. In this context rabbits are a cost-efficient and perhaps convenient alternative to other large eye animal models.

Retinal pigment epithelium (RPE) replacement strategies and gene-based therapy are considered for several retinal degenerative conditions. For clinical translation, large eye animal models are required to study surgical techniques applicable in patients. Here we present a rabbit model for subretinal surgery geared towards RPE transplantation, which is versatile and cost-efficient.

Age related macular degeneration (AMD), retinitis pigmentosa, and other RPE related diseases are the most common causes for irreversible loss of vision in ...

Effects of Allogeneic Platelet-Rich Plasma (PRP) on the Healing Process of Sectioned Achilles Tendons of Rats: A Methodological Description

This article describes the experimental procedures used to observe if PRP can positively affect tendon healing. There are 4 main steps to follow: induce a lesion in the Achilles tendon; prepare PRP and inject it (or the saline solution); remove the tendon; and perform biomechanical, molecular, and histological evaluations. At each step, all the procedures and methods are described in detail, so they can be reproduced easily.
Achilles tendons have been surgically sectioned (removal of a 5-mm long section). Afterwards, PRP or saline solution was injected to study whether PRP has a positive effect on the healing of the tendon. Three groups of 40 animals (a total of 120 rats were used in this study) were subdivided into 2 subgroups: PRP injection group and a saline injection control group. Rats were sacrificed at increasing time points (Group A: 5 days; Group B: 15 days; Group C: 30 days) and tendons were removed. 90 tendons underwent biomechanical testing before performing transcriptomic analysis and the 30 remaining tendons were submitted to histological analysis.

Effects of Allogeneic Platelet-Rich Plasma PRP on the Healing Process of Sectioned Achilles Tendons of Rats: A Methodological Description

This protocol describes the evaluation process of healing tendons in rats that have been injected with allogeneic platelet rich plasma (PRP) or saline solution after removing part of the Achilles tendon. The progress of tendon healing is evaluated at several time points using different types of analyses.

This article describes the experimental procedures used to observe if PRP can positively affect tendon healing. There are 4 main steps to follow: induce a ...

Ultrasonography in Experimental Reproductive Investigations on Rats

With the development of assisted reproductive technology and the ethical limitations of research on humans, rat animal models have been widely used in reproductive medicine. In the past, the study of reproductive system development in rodents has been based on one-time histological examination of excised tissues. Recently, with the development of high-resolution transabdominal ultrasound, high-quality sonography can now be performed to evaluate the reproductive organs of rats, allowing a new method for studying the reproductive system. Images were obtained using a high-resolution ultrasonographic system. Gynecological ultrasonography was performed on 28 eight-week-old non-pregnant rats and 5 pregnant Sprague-Dawley rats. We describe how to recognize organs of the reproductive system and associated structures in typical views during different phases of the estrus cycle. Color flow Doppler was used to measure uterine artery blood flow and evaluate uterine blood flow pattern changes during different stages of pregnancy. We have demonstrated that ultrasound exploration is a useful method for evaluating changes in internal reproductive organs. Its use raises the possibility of conducting additional experiments, including medical or surgical procedures, and provides the ability to monitor sonographic changes to internal organs without sacrificing animals.

This manuscript describes the utility of ultrasound performed on female rats to design experimental models for reproductive and gynecological investigation. A step-by-step explanation of how to perform ultrasonographic evaluation is shown.

With the development of assisted reproductive technology and the ethical limitations of research on humans, rat animal models have been widely used in ...

Improved Method for the Establishment of an In Vitro Blood-Brain Barrier Model Based on Porcine Brain Endothelial Cells

The aim of this protocol presents an optimized procedure for the purification and cultivation of pBECs and to establish in vitro blood-brain barrier (BBB) models based on pBECs in mono-culture (MC), MC with astrocyte-conditioned medium (ACM), and non-contact co-culture (NCC) with astrocytes of porcine or rat origin. pBECs were isolated and cultured from fragments of capillaries from the brain cortices of domestic pigs 5-6 months old. These fragments were purified by careful removal of meninges, isolation and homogenization of grey matter, filtration, enzymatic digestion, and centrifugation. To further eliminate contaminating cells, the capillary fragments were cultured with puromycin-containing medium. When 60-95% confluent, pBECs growing from the capillary fragments were passaged to permeable membrane filter inserts and established in the models. To increase barrier tightness and BBB characteristic phenotype of pBECs, the cells were treated with the following differentiation factors: membrane permeant 8-CPT-cAMP (here abbreviated cAMP), hydrocortisone, and a phosphodiesterase inhibitor, RO-20-1724 (RO). The procedure was carried out over a period of 9-11 days, and when establishing the NCC model, the astrocytes were cultured 2-8 weeks in advance. Adherence to the described procedures in the protocol has allowed the establishment of endothelial layers with highly restricted paracellular permeability, with the NCC model showing an average transendothelial electrical resistance (TEER) of 1249 &#177; 80 &#937; cm2, and paracellular permeability (Papp) for Lucifer Yellow of 0.90 10-6 &#177; 0.13 10-6 cm sec-1 (mean &#177; SEM, n=55). Further evaluation of this pBEC phenotype showed good expression of the tight junctional proteins claudin 5, ZO-1, occludin and adherens junction protein p120 catenin. The model presented can be used for a range of studies of the BBB in health and disease and, with the highly restrictive paracellular permeability, this model is suitable for studies of transport and intracellular trafficking.

Improved Method for the Establishment of an In Vitro Blood-Brain Barrier Model Based on Porcine Brain Endothelial Cells

The aim of the protocol is to present an optimized procedure for the establishment of an in vitro blood-brain barrier (BBB) model based on primary porcine brain endothelial cells (pBECs). The model shows high reproducibility, high tightness, and is suitable for studies of transport and intracellular trafficking in drug discovery.

The aim of this protocol presents an optimized procedure for the purification and cultivation of pBECs and to establish in vitro blood-brain barrier (BBB) ...

Microscopy Based Methods for the Assessment of Epithelial Cell Migration During In Vitro Wound Healing

Cell migration is a mandatory aspect for wound healing. Creating artificial wounds on research animal models often results in costly and complicated experimental procedures, while potentially lacking in precision. In vitro culture of epithelial cell lines provides a suitable platform for researching the cell migratory behavior in wound healing and the impact of treatments on these cells. The physiology of epithelial cells is often studied in non-confluent conditions; however, this approach may not resemble natural wound healing conditions. Disrupting the epithelium integrity by mechanical means generates a realistic model, but may impede the application of molecular techniques. Consequently, microscopy based techniques are optimal for studying epithelial cell migration in vitro. Here we detail two specific methods, the artificial wound scratch assay and the artificial migration front assay, that can obtain quantitative and qualitative data, respectively, on the migratory performance of epithelial cells.

Microscopy Based Methods for the Assessment of Epithelial Cell Migration During  In Vitro Wound Healing

This manuscript describes how incision-like lesions made on cultured epithelial cell monolayers conveniently model wound healing in vitro, allowing for imaging by confocal or laser scanning microscopy, and which can provide high-quality quantitative and qualitative data for studying both cell behavior and the mechanisms involved in migration.

Cell migration is a mandatory aspect for wound healing. Creating artificial wounds on research animal models often results in costly and complicated ...

An In Vivo Method for Evaluating the Gut-Blood Barrier and Liver Metabolism of Microbiota Products

The gut-blood barrier (GBB) controls the passage of nutrients, bacterial metabolites and drugs from intestinal lumen to the bloodstream. The GBB integrity is disturbed in gastrointestinal, cardiovascular and metabolic diseases, which may result in easier access of biologically active compounds, such as gut bacterial metabolites, to the bloodstream. Thus, the permeability of the GBB may be a marker of both intestinal and extraintestinal diseases. Furthermore, the increased penetration of bacterial metabolites may affect the functioning of the entire organism.
Commonly used methods for studying the GBB permeability are performed ex vivo. The accuracy of those methods is limited, because the functioning of the GBB depends on intestinal blood flow. On the other hand, commonly used in vivo methods may be biased by liver and kidney performance, as those methods are based on evaluation of urine or/and peripheral blood concentrations of exogenous markers. Here, we present a direct measurement of GBB permeability in rats using an in vivo method based on portal blood sampling, which preserves intestinal blood flow and is virtually not affected by the liver and kidney function. 
Polyurethane catheters are inserted into the portal vein and inferior vena cava just above the hepatic veins confluence. Blood is sampled at baseline and after administration of a selected marker into a desired part of the gastrointestinal tract. Here, we present several applications of the method including (1) evaluation of the colon permeability to TMA, a gut bacterial metabolite, (2) evaluation of liver clearance of TMA, and (3) evaluation of a gut-portal blood-liver-peripheral blood pathway of gut bacteria-derived short-chain fatty acids. Furthermore, the protocol may also be used for tracking intestinal absorption and liver metabolism of drugs or for measurements of portal blood pressure.

An In Vivo Method for Evaluating the Gut-Blood Barrier and Liver Metabolism of Microbiota Products

The access of nutrients, microbiota metabolites and medicines to the circulation is controlled by the gut-blood barrier (GBB). We describe a direct method for measuring the GBB permeability in vivo, which, in contrast to commonly used indirect methods, is virtually not affected by liver and kidney functions.

The gut-blood barrier (GBB) controls the passage of nutrients, bacterial metabolites and drugs from intestinal lumen to the bloodstream. The GBB integrity ...

Measuring the Effects of Bacteria and Chemicals on the Intestinal Permeability of Caenorhabditis elegans

In living organisms, intestinal hyperpermeability is a serious symptom that leads to many inflammatory bowel diseases (IBDs). Caenorhabditis elegans is a nonmammalian animal model that is widely used as an assay system due to its short lifespan, transparency, cost-effectiveness, and lack of animal ethics issues. In this study, a method was developed to investigate the effects of different bacteria and 3,3'-diindolylmethane (DIM) on the intestinal permeability of C. elegans with a high-throughput image analysis system. The worms were infected with different gut bacteria or cotreated with DIM for 48 h and fed with fluorescein isothiocyanate (FITC)-dextran overnight. Then, the intestinal permeability was examined by comparing the fluorescence images and the fluorescence intensity inside the worm bodies. This method may also have the potential to identify probiotic and pathogenic intestinal bacteria that affect intestinal permeability in the animal model and is effective for examining the effects of harmful or health-promoting chemicals on intestinal permeability and intestinal health. However, this protocol also has some considerable limitations at the genetic level, especially for determining which genes are altered to control illness, because this method is mostly used for phenotypic determination. In addition, this method is limited to determining exactly which pathogenic substrates cause inflammation or increase the permeability of the worms' intestines during infection. Therefore, further in-depth studies, including investigation of the molecular genetic mechanism using mutant bacteria and nematodes as well as chemical component analysis of bacteria, are required to fully evaluate the function of bacteria and chemicals in determining intestinal permeability.

Measuring the Effects of Bacteria and Chemicals on the Intestinal Permeability of Caenorhabditis elegans

This protocol describes how to measure intestinal permeability of Caenorhabditis elegans. This method is helpful for basic biological research on intestinal health related to the interaction between intestinal bacteria and their host and for screening to identify probiotic and chemical agents to cure leaky gut syndrome and inflammatory bowel diseases.

In living organisms, intestinal hyperpermeability is a serious symptom that leads to many inflammatory bowel diseases (IBDs). Caenorhabditis elegans is a ...